bell gettingstarted

Click here to load reader

Post on 05-Apr-2018

217 views

Category:

Documents

0 download

Embed Size (px)

TRANSCRIPT

  • 8/2/2019 Bell GettingStarted

    1/94

    Simpl I Q f or St eppersSimpl I Q f or St eppersSimpl I Q f or St eppersSimpl I Q f or St eppers

    Get t i ng St a r t ed &Tun ing and Com m ission ing

    Guide

    Ver 1 .1 - June 200 9

  • 8/2/2019 Bell GettingStarted

    2/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 2

    Not ice This guide is delivered su bject to the following conditions and restrictions:

    This guide contains prop rietary information belonging to Elmo Motion

    Control Ltd. Such information is supp lied solely for the pu rpose of assisting

    user s of the Bell servo d rive in its installation.

    The text and grap hics includ ed in this manu al are for the pu rpose of

    illustration and reference only. The specifications on wh ich they are based

    are subject to change w ithout notice.

    Elmo Motion Cont rol and th e Elmo Motion Control logo are trademarks of

    Elmo Motion Control Ltd.

    Information in this docum ent is subject to change w ithout n otice.

    Docum ent N o. MAN-BELGS

    Copyright 2009

    Elmo Motion Control Ltd.

    All rights reserved

    The mod el that is currently available is the

    BEL-5/ 100.

    Rev i s i on H i sto ry : Ver . 1.0 January 2008 (MAN -BELIG.PDF)

    Ver 1.1 June 2009

    Elmo Motion Control Ltd.64 Gisin St., P.O. Box 463

    Petach Tikva 49103

    Israel

    Tel: +972 (3) 929-2300

    Fax: +972 (3) 929-2322

    [email protected] c.com

    Elmo Motion Control Inc.42 Technology Wa y

    Nashua, NH 03060

    USA

    Tel: +1 (603) 821-9979

    Fax: +1 (603) 821-9943

    [email protected] c.com

    Elmo Motion Control Gmb H

    Steinkirchring 1D-78056, Villingen-Schwenningen

    Germany

    Tel: +49 (0) 7720-85 77 60

    Fax: +49 (0) 7720-85 77 70

    [email protected] c.com w w w . e l m o m c . c o m

    http://www.elmomc.com/mailto:[email protected]:[email protected]:[email protected]
  • 8/2/2019 Bell GettingStarted

    3/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 3

    Con ten ts

    Ch ap ter 1:Introd uction ...............................................................................................................5

    1.1 Qu alified Person nel ....................................................................................................7

    1.2 Wor king with th is Docu m ent ....................................................................................7

    Ch ap ter 2:Elemen ts ...................................................................................................................8

    2.1 Estab lishing Com municat ion with a Drive ..............................................................8

    2.1.1 Changin g the Com munication Param eters ....................................................................... 11

    2.2 Ap plication Parameters and Program ming ........................................................... 13

    2.2.1 Flash , RAM and Tables......................................................................................................... 13

    2.2.2 Creat ing an Ap plication File................................................................................................ 14

    2.2.3 Dow nload ing an Ap plication File....................................................................................... 14

    2.2.4 Observing the Con tent s and Editing an Application File................................................ 15

    2.3 Firm ware....................................................................................................................15

    2.3.1 Version Verificat ion .............................................................................................................. 15

    2.3.2 Normal Firm ware Dow nload ..............................................................................................16

    2.3.3 Abn orm al (from Boot) Firmware Down load .................................................................... 16

    2.4 The Conductor Wiza rd .............................................................................................17

    2.4.1 The Conductor Tabs .............................................................................................................. 17

    2.4.2 The Expert List ....................................................... ........................................................... ..... 18

    2.4.3 Accep ting a Chan ge of Parameters .....................................................................................20

    Ch ap ter 3:Gettin g Started w ith Sen sors an d M otion Con trol Setu p ................................21

    3.1 Int roduction ............................................................................................................... 213.1.1 Tune the Drive to the Motor ................................................................................................ 21

    3.1.2 Tune the Mot ion Con troller ................................................................................................. 21

    3.1.3 Database Maintenance.......................................................................................................... 21

    3.2 Abort and Enab le Switches ...................................................................................... 21

    3.2.1 Brakes..................................................... ........................................................ ......................... 22

    3.2.2 Ap plication Limits ................................................................................................................23

    3.3 Set up the Sensor s ..................................................................................................... 25

    3.3.1 Settin g up Sensor #1 ............................................................................................................. 26

    3.4 Tunin g the Driv e to the Motor ................................................................................. 27

    3.4.1 Selecting the Motor Typ e ..................................................................................................... 283.4.2 Tuning or Checking th e Cu rrent Con trol .......................................................................... 29

    3.5 Commuta tion.............................................................................................................30

    3.6 Motion Tuning...........................................................................................................32

    3.6.1 Torqu e Drive .......................................................................................................................... 32

    3.6.2 Stepper Drives with no Com mutation Sensor................................................................... 33

    3.6.3 Speed and Position Con trol ................................................................................................. 35

    3.7 Fine Tuning ................................................................................................................45

    3.7.1 Coggin g Com pensat ion ........................................................................................................ 45

    3.7.2 Fine Tunin g an Analog Encoder ......................................................................................... 49

    3.8 Database Maintenance.............................................................................................. 51

  • 8/2/2019 Bell GettingStarted

    4/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 4

    Chapter 4:Advanced Control Tuning.....................................................................................52

    4.1 Star t Step Contro l ...................................................................................................... 52

    4.2 Identifica tion ............................................................................................................. 52

    4.2.1 Identificat ion and Uncertain ty ............................................................................................ 53

    4.2.2 Identificat ion Resu lts Managem ent .................................................................................... 534.2.3 Identificat ion Wor k Poin t..................................................................................................... 54

    4.2.4 Selecting the Identificat ion Frequencies............................................................................. 55

    Append ix A: Man ua l Tu n ing of Sp eed and Posit ion Con trol ....................................60

    A.1 Scope...........................................................................................................................60

    A.2 Safety ..........................................................................................................................60

    A.3 Make it Simple........................................................................................................... 61

    A.4 Keep Margins ............................................................................................................62

    A.5 The Basic Concep ts ...................................................................................................62A.5.1 Fixed- vs. Gain -scheduled Con trollers ...............................................................................62A.5.2 Resonance and Notch Filter s ............................................................................................... 63

    A.5.3 High Frequency Noise and Low-pass Filter s .................................................................... 63

    A.5.4 Evalu ating a Step Respon se Rise Time, Settling Time, and Oversh oot. ..................... 64

    A.6 The Exam ple System ................................................................................................. 65

    A.7 Testin g th e Response of a Con troller ......................................................................66

    A.7.1 Cu rrent Limits ....................................................................................................................... 66

    A.7.2 Record ing th e Experiment Results ......................................................................................66

    A.8 Fixed Gain Manual Tunin g for a Speed Loop ........................................................67

    A.8.1 Manu al Tunin g of a PI Con troller .......................................................................................67A.8.2 Man ual Tun ing of a PI Con troller and a Low Pass Filter ................................................ 72

    A.8.3 Manual Tuning of a PI Con troller and a Notch Filter ...................................................... 74

    A.9 Executing Man ua l Tuning for a Cascad ed Position Controller ............................ 78

    A.10 Manual Tun ing of Gain Sched uling ........................................................................79

    A.10.1 Manu al Gain Sched uling...................................................................................................... 79

    A.10.2 Au tom atic Gain Sched u ling ................................................................................................. 80

    App end ix B: A Sh ort Cou rse in Linear Con tro l ............................................................82

    B.1 Linear Syst em s and Tran sfer Fun ctions.................................................................. 82

    B.2 Mathem atical Mod els for LTI Syst em s ...................................................................83

    B.3 Motor System s Mod els .............................................................................................85

    B.3.1 A Simple Model ...................................................... .......................................................... ..... 85

    B.3.2 Mod el with Flexible Transmission (resonance) ................................................................ 86

    B.4 Feed back Con trol ...................................................................................................... 90

    B.4.1 Why Feed back is Requ ired .................................................................................................. 90

    B.4.2 Open Loop, Gain Margin and Phase Margin, Band wid th and Stability ....................... 91B.4.3 P, PD, PI and PID Con troller s.............................................................................................. 92

  • 8/2/2019 Bell GettingStarted

    5/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 5

    Chap t e r 1 : I n t r oduc t i on The Simp lIQ docum entation and sup port software is divid ed into the following

    areas:

    Usage Phase Documen t Tool

    Exploratory Sales docum ents for Simp lIQ and Bell

    Planning/ configuration Simp lIQ for Stepp ers Sizer configuration

    tool

    Decision/ ord ering Elmo Catalog and website

    Installation/ assembly Device specific installation guid e, e.g.

    Bell Installation Guid e

    Comm issioning and Getting Started This guid eComposer Guide

    Usage/ operation Simp lIQ for Stepp ers Comm and Reference

    Manual

    SimplIQ Programm ing and Language Guid e

    Simp lIQ for Stepp ers App lication N ote

    DS301 docum ent

    DS402 docum ent

    The diagram below sh ows the Simp lIQ for Stepp ers docum entation set:

    As dep icted in th e previous figure, this Getting Started & Tun ing gu ide is an

    integral part of the Bell documen tation set, comp rising:

  • 8/2/2019 Bell GettingStarted

    6/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 6

    The SimplIQ for Steppers Command Reference and the SimplIQ for Steppers

    Application Note, wh ich d escribe in d etail each software comm and used to

    man ipu late the Bell motion controller.

    The SimplIQ Programming and Language Manual, wh ich includes explanations of

    all the software tools that are part of Elmos Comp oser software environm ent.

    TheBell Stepper Drive Installation Guide, w hich describes, in d etail, the differences

    that h ave been introdu ced by the Bell to SimplIQ to cover 2-phase motors an d

    steppers.

    The SimplIQ for Steppers Getting Started Guide, which describes how to set up an d

    tune the stepper d rive.

    Note that th is documen tation does not contain all the information for all prod uct

    types an d cannot take into account every p ossible aspect of installation, operation,

    or maintenan ce.

    Su p p o r t So f tw a re

    This Getting Started m anu al relies heavily on the Comp oser and Cond uctor tools.

    The Composer is a supp ort progr am by Elmo for Simp lIQ.

    The Composer su pp lies the basic services for comm un icating w ith d rives and

    collecting d ata from th em.

    The Condu ctor is a tun ing tool d eveloped b y Digital Feedback Technologies. The

    Cond uctor enables the Simp lIQ param eters to be tuned .

    The Condu ctor is norm ally called from th e Comp oser environment.

    Aud ience and Ob j ect i v eThis document is intend ed for machine man ufacturers, commissioning engineers,

    and service personnel wh o use the Simp lIQ d rive system.

    It is intended to m ake you familiar with the software environment p rovided for

    Simp lIQ. With this environment, you will be able to set up your dr ive with relative

    ease.

    This man ual is intend ed to give you a solid starting point. Once you u nd erstand th e

    environm ent's core logic, you can wor k efficiently by referring to th e online help. In

    add ition, there is a lot of relevant information in other the m anu als of the

    documentation set.

    Pre requ is i te

    This manu al assum es that you installed th e drive correctly according to the Bell

    Stepp er Drive Installation Gu ide.

    D a n g e r a n d Wa rn i n g Sy m b o l s

    The following d anger and warn ing notices are used in th is document:

    Danger:

    This symbol indicates that death , severe personal injury, or

    substantial prop erty dam age may result if prop er precautions are not

    taken.

  • 8/2/2019 Bell GettingStarted

    7/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 7

    Caution (With or w ithout a w arning tr iangle, accord ing to severity):

    This symbol indicates that m inor personal injury or p roperty d amage

    may resu lt if proper precautions are not taken.

    Note:

    This symbol highlights sup plementar y information

    This symb ol indicates that the top ic is normally han dledautom atically by supp ort software, and the m aterial is only given for

    enhanced u nderstanding.

    1.1 Qual i f i ed Personn e l

    For this docum ent, Qualified Personnel means:

    For devices that ar e 60 V or less: som eone familiar w ith the dr ive, following a

    training course, after reading m aterial, and w ith ad equate technical education.

    For higher voltage drives it has the ad ditional meaning of someone licensed to

    deal w ith electricity of the relevant voltage an d pow er, according to local

    regulations.

    Up-to-date information about ou r prod ucts can be foun d on th e Internet at the

    following ad dr ess: www.elmomc.comESD Not ices

    Caution:

    The SimplIQ drives are Electrostatic-Sensitive Devices (ESD). This

    means th at hand ling them incorrectly may d amage them . Please

    carefully read the ESD p recautions in the Installation Gu ide.

    Danger:

    All the devices mu st be installed accord ing to the d evice-specific

    Installation Gu ide. Special attention m ust be given to earth

    groun ding an d for high voltage connections and insulations.

    Before d ealing with a d evice, verify it is in the p roper condition, and

    that it is not d amag ed mechanically or electrically.

    1 . 2 W or k i ng w i t h t h i s Docum en t

    We recommend new u sers to:

    Thorough ly read Chapter 2: Elements.

    Go through Chap ter 3: Getting Started .

    Chapter 4: Ad vanced Control Tuning is for experienced control practitioners, who

    can exploit the extra flexibility of the Sim plIQ environm ent beyon d th e "Getting

    Start ed" level.

    The append ices give more general data on the linear system and on m anu al tuning.

    http://www.elmomc.com/http://www.elmomc.com/http://www.elmomc.com/
  • 8/2/2019 Bell GettingStarted

    8/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 8

    Chapt e r 2 : Elem ent s This section d eals with th e m ost basic concepts of drive comm issioning:

    Communication

    Application programm ing

    Firmware

    The Condu ctor Wizard

    2 .1 Es tab l i sh ing Com m un ica t i on w i th a Dr i ve

    When you op en the Comp oser it tries to comm un icate with the drive. The

    commu nication m ay be one of the following:

    RS-232

    CANopen

    The Composer app lication can be connected simu ltaneously to more than on e

    dr ive. In this m anu al we focus on single drive connections.

    The Comp oser can comm un icate with mu ltiple drives and d efine a network

    setup . For further details, refer to the Comp oser online help.

    When you open the Comp oser, the following w indow opens:

    Figure 1: Starting the Composer

    ClickOpen Communication Directly. The following w indow opens:

  • 8/2/2019 Bell GettingStarted

    9/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 9

    Figure 2: Compos er connecti ng w indow

    Ignore the Application Name field.

    Look at Last Su ccessful Comm un ication Prop erties. If the p roperties listed th ere

    are as required , clickFinish . Oth erw ise, clickProperties:

    For RS-232 you n eed to set the nu mber of the COM p ort in u se, the bau d rateand the p arity. The comm un ication is always 8 bits in a by te, and it has on e stop

    bit.

    For CAN you need to set the ID and the bau d rate. In ad dition, you will have to

    select the CAN ad apter from the supp orted typ es.

    Then clickFinish . The Composer opens to the m ain window :

    Figure 3: The main Composer w indow

  • 8/2/2019 Bell GettingStarted

    10/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 10

    The Smart Terminal lets you en ter comman ds m anu ally please refer to the

    Simp lIQ for Stepp ers Comm and Reference Manual. To send a comman d, typ e it

    in the Enter Comman d field a nd clickSend .

    Notes:

    At the connection step you need to know the drive commu nication param eters.

    It is possible to change th e dr ive comm un ication p arameters only later, after

    commu nication is established .

    If you d o not know the CAN ID, you may either:

    o Connect first with RS-232, then ask for PP[13] (can ID) and PP[14] (CAN

    baud rate).

    o Use the DSP 305 protocol to find ou t the drive p aram eters (you will need

    your ow n CAN ap plication for that).

    The drive stores a lot of information about itself internally and this enablesthe Comp oser to interact with a m ultitud e of drive typ es. When a Com poser first

    meets a d rive version it upload s this internal information. You w ill see the

    following window :

    Figure 4: Uploading personality dat a

    The next time you contact the sam e drive version, the Comp oser already has all

    its personality data stored an d w ill not ask you to w ait again.

    If the dr ive lost its software, for examp le by a power-dow n d uring firmw are

    dow nloading, it w ill withd raw to a very limited d efault, or "boot" software. With

    this boot, it is only possible to d own load the n ew firmw are version. The

    commu nication p arameters in the "boot" state are fixed (not affected by an y u ser

    setting):

    Baud rate of 57600 and no pa rity for RS-232.

    Baud rate of 500000 and CAN ID of 127 for CAN .

    After you set the correct comm un ication p aram eters, you will see the following

    message:

  • 8/2/2019 Bell GettingStarted

    11/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 11

    Figure 5:Bo ot sof tw are m essage

    ClickYes to open the wind ows related to d ownloading the firmware.

    2.1 .1 Chang in g th e Com m un ica t ion Param eters

    2.1 .1 .1 Chang ing t he RS-23 2 Com m unica t ion Rate and

    Par i t y

    First set the desired param eters in the Com poser smart t erminal:

    PP[2] RS-232 baud ra te. 5: 115,200;

    4: 57,600

    3: 38,400

    2: 19,200

    1: 9,600

    0: 4,800

    PP[4] RS-232 parity. 0: None

    1: Even

    2: Od d

    Setting PP[2] and PP[4] alone d oes not change the comm un ication setting , so the

    Comp oser can continue comm un ication with the drive.

    Write, for exam ple, PP[2]=5. This is a requ iremen t for a bau d rate of 115200/ sec.

    Next w rite PP[2]=1. This is a comman d to accept th e new setting. Almost

    imm ediately, you w ill see:

    Figure 6: Communication disconnect m essage

    This is because you changed th e baud rate so the comm un ications from th e

    Com poser fail. ClickYes to d isconnect, than re-open commu nication by clicking

    Connect.

  • 8/2/2019 Bell GettingStarted

    12/94

  • 8/2/2019 Bell GettingStarted

    13/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 13

    Figure 9: The Connect but t on, circled in red

    Next select the new bau d-rate using th e Properties button (see Figure 2).

    When th e Composer Smart Term inal re-opens, you m ay use the SV comman d to

    make the new baud setting permanent.

    2 .2 App l i ca t i on Param ete rs and Progr am m ing

    When you commission a dr ive, you create an Ap plication. An App lication refers

    to the entire data set you d own load and store into the drive. The app lication

    includes:

    Parameters to store perm anently in the d rive, such as controller coefficients.

    User program s: please refer to the Simp lIQ Programm ing and Language Guid e.

    The Composer packs all the non -volatile param eters and the User Program in a

    single file, w ith the .dat extension.

    The Composer can later use this .dat file to prog ram m any am plifiers to the same

    parameters and User Program.

    2.2 .1 Flash, RAM and Tables

    The drive contains the following m emory typ es:

    Memory Type Used for

    Serial Flash N on-volatile This flash stores all the non -volatile

    param eters, as well as the User Program

    Table Flash Non-Volatile This high speed flash stores the m otion

    correction tables for real-tim e use.

    The data in th e Table Flash mu st be an

    iden tical copy of the da ta in the serial flash.

    RAM Volatile Stores a volatile copy of the serial-flash

    param eters for real-time high-speed use.

    When th e drive p owers-on, it loads th e RAM as a copy of the table flash.

    It also com pares the Table Flash w ith the Serial Flash. If the conten ts are not -

    equal, you w ill not be able to start the m otor un til the situation is corrected.

    When you comm unicate with the d rive the parameters you mod ify are in the

    RAM. When you w rite, for exam ple, KI[1]=1, you u pd ate the copy of KI[1] in the

    RAM. The p aram eter KI[1] has a copy in the serial flash w hich rem ains as is.

    When you wan t to synchronize the RAM and the serial flash, you can:

    Use the SV comm and to copy th e entire RAM conten ts into the serial flash (forexample, after you tu ned som e param eters).

  • 8/2/2019 Bell GettingStarted

    14/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 14

    Use the LD comm and to copy th e entire Serial Flash contents into the RAM.

    When you wan t to syn chronize the Table Flash and the Serial Flash, use th e SI=1

    command.

    Notes:

    The SV, LD, and SI comm and s w ork on an entire d ata set. There is no w ay to

    save some of the param eters and not save others.

    SV does not au tom atically synchronize th e Table Flash because Table Flash

    synchronizations take a long time. Table Flash syn chronizations are carried out

    very rarely.

    2.2.2 Creat ing an Appl ica t io n Fi le

    In this Section we will create an ap plication file in the PC com puter.

    From the m enu select File>Save App lication .

    The Composer will prepare to pa ck all the param eters and the User Program into

    an application file. It displays the following message:

    Figure 10: Save application m essage

    The Comp oser up loads the p arameters d irectly from the serial flash. It enables

    you to synchronize the p arameters in th e Serial Flash to the copy in the RAM

    , or to skip synchronization .

    After this enter a file nam e.

    2.2 .3 Dow n load ing an App l i cat ion Fi le

    In order to distribute an app lication from a d ata file to a driver, do the following:

    From the m enu select File>Open App lication . The following w indow opens:

  • 8/2/2019 Bell GettingStarted

    15/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 15

    Figure 11: Open Application w indow

    Upon selection, look at th e Commun ication Info data box. Verify th at the

    commu nication param eters there are correct, or clickChange to edit them.

    Then clickDownload to complete the downloading.

    After d own loading, the Serial Flash and the Table Flash may become n on-

    synchronized, and in this case you n eed to enter SI=1 at the smart term inal in

    ord er to comp lete the synchronization.

    2.2 .4 Observ ing th e Cont en ts and Ed i t in g an App l i ca t ionFi le

    The Comp oser has a tool called th e App lication Editor.

    2 . 3 F i r m w a r e

    This section deals with keeping the d rive softwar e version u p-to-date.

    The drive m ust be load ed w ith the correct software to operate. You w ill norm ally

    receive the drive loaded with t he correct software from the d ealer. Firmw are

    up grad es are, how ever, available from time to time. You can d own load the latest

    firmw are from th e Elmo w eb site. It is a text file with th e .abs extension .

    2.3.1 Vers ion Ver i f ica t ion

    For version v erification, use the VR comm and . It shou ld retu rn som ething like

    Bell 2.02.07.21 10Dec2007. You can compare this string with the latest available

    firmw are at the Elmo w eb site.

  • 8/2/2019 Bell GettingStarted

    16/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 16

    2 . 3 .2 No rm a l Fi rm w are Dow n load

    In the Composer Smart Terminal, select Tools>Firmware D own load . The

    following w indow opens:

    Figure 12:Do w nl oa d fi rmw are w in do w

    Use the Browse bu tton to select the firmw are .abs file, and then clickOK.

    The firmw are starts to load, and you can w atch the progress bar:

    Figure 13: The Firmw are progress bar

    The firmw are is internally divid ed into a few sections, and you can observe the

    part that is currently being loaded. The first part is "Firmw are dow nloading" and

    the last part is "Extended firm ware d own loading".

    When it has finished loading, a m essage asks you to reboot the d rive by

    d isconnecting it from the electricity.

    2 . 3 .3 A bno rm a l ( f r om Boo t ) Fi rm w are Dow n load

    If the dr ive lost its software, for example by a pow er-dow n d uring firmw are

    dow nloading, it w ill withd raw to a very limited d efault, or "boot" software. With

    this boot, it is only possible to d own load the n ew firmw are version. The

    commu nication p arameters in the "boot" state are fixed (not affected by an y u ser

    setting):

    Baud rate of 57600 and no pa rity for RS-232.

    Baud rate of 500000 and CAN ID of 127 for CAN .

    After you set the correct comm un ication p aram eters, you will see the following

    message:

  • 8/2/2019 Bell GettingStarted

    17/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 17

    Figure 14: Firmw are message

    2.4 The Cond uc to r W izard

    2.4.1 The Cond ucto r Tabs

    The Condu ctor is the main t ool for tu ning th e Simp lIQ control functions.

    Figure 15: The Conductor w indow

    The Cond uctor manages some experimen ts for the tuning current and motion

    controls. You have a lot of flexibility in m anaging th e experiment, but y ou d o not

    need to be an expert.

    A color code d efines which param eter fields you may leave as is, and w hich require

    your attent ion and u nd erstanding refer to the figure below.

  • 8/2/2019 Bell GettingStarted

    18/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 18

    Figure 16: User edit able fields in a t uning experim ent

    2.4.2 The Exp er t Lis t

    The Expert list is a tool for observing an d editing th e drive p aram eters. It gives

    extra flexibility for the experienced u ser, and it lets you tr ack wh ich drive

    parameters you changed and h ow.

    Expert lists and the Condu ctor wizards work w ith the param eters in RAM

    only. Your work is volatile (will disapp ear at th e next pow er-on or LD

    comman d), until you clickSave in Flash in the Database tab.

    When you open th e Expert List using the Expert list button , you see the

    following:

  • 8/2/2019 Bell GettingStarted

    19/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 19

    Figure 17:Expert li st w in dow

    Here you see, and may edit (simply by clicking the valu e), each of the p arametersthat this wizard pad controls.

    The Expert List find s wh ich p aram eters relate to a given Cond uctor tab u sing a

    keyword ; Cond uctor tabs use keyword s that are delimited by $ signs at both

    ends.

    You can, how ever, select anoth er keyword from the list, or type a k eyword

    m anu ally. Then clickSearch .

    If the Expert List detects a chan ge wh en you exit, it will display :

    Figure 18:Expert Li st exi t com pariso n

  • 8/2/2019 Bell GettingStarted

    20/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 20

    2.4.3 Accept ing a Chang e of Param eter s

    When you change drive param eters with the Condu ctor, and you exit a tab, the

    condu ctor displays an exit comp arison, as in Figure 18.

    After confirmation, the p arameters are accepted and cannot be restored by th e

    Conductor.

    Expert lists and the Condu ctor wizards work w ith the param eters in RAM only.

    Your w ork is volatile (will disapp ear at the next pow er-on or LD comman d),

    until you clickSave in Flash in the Database tab.

  • 8/2/2019 Bell GettingStarted

    21/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 21

    Chap t e r 3 : Ge t t i ng St a r t ed w i t h

    Sensors and Mot ion Con t ro l Se tu p

    3 . 1 I n t r o d u c t i o nTuning a SimplIQ drive to a m otor is an ord ered, step-by-step p rocess. In this

    "Getting Started" chap ter, we go throu gh th e setup p rocess step by step.

    Note th at this chap ter does not contain all the detailed information for all prod uct

    types and cannot take into accoun t every possible aspect of the drive setup .

    3.1 .1 Tune the Dr ive to the Moto r

    All motor an d ap plication types:

    Set the sw itch functions for limits; enable functions, br akes, etc. This will create

    the initial cond itions for the m otor to w ork.

    Set the ap plication limits for current, speed, an d position. This will prevent

    system constraints being violated later on.

    Defining th e sensors.

    Selecting th e motor typ e (DC, Stepper , Bru shless).

    Tuning th e curr ent controller.

    Brush less motors only:

    Commu tation tu ning (finding how to pow er the stator so that the m otor will

    develop m aximu m torqu e in the desired direction).

    3.1 .2 Tune th e Mot ion Cont ro l le r

    For open loop stepp ing app lications, you on ly need to set few p arameters.

    If you h ave a motion sensor, you m ay wan t the following:

    Tune speed and position controls.

    Set corrections for motor cogging and define the speed -depend ent corrections

    to the curren t loop.

    3.1.3 Database Main t enance

    All the steps un til now have m anipu lated variables in the d rive's datab ase. The

    last step is to check datab ase validity, and to save the outcome in a perm anent

    (flash) memory.

    3 .2 Abor t and Enab le Sw i t ches

    First, set the enabling sw itches.

    The drive has several digital inpu ts (dep ending on the d rive type). There are

    several automatic fun ctions that m ay be assigned to dr ive digital inpu ts.

    It is imp ortant th at at this stage you d efine which switches are used to abort or tostop m otion, as well as limit sw itches w hen app licable.

  • 8/2/2019 Bell GettingStarted

    22/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 22

    For this pu rpose, use the Inp ut Logic tab in the Smart Terminal.

    Figure 19:Defi ni ng in pu t lo gic

    For a detailed description of the fun ctions that may be assigned to d igital inpu ts,

    refer to th e IL[N] comm and in the SimplIQ for Stepp ers Comm and Reference

    Manual.

    Correct digital inpu t definitions help to gu arantee that the d rive

    generates only safe motions in the course of the tun ing p rocess.

    Incorrect digital inp ut settings may p revent dr ive motion or tuning.

    3.2 .1 B rakes

    If a brake is installed an d you wan t to operate it autom atically wh en the m otor

    starts, set it up now .

    First select the brake engage an d release delays. For this p urp ose select th e

    Protections>Brake tab in th e Comp osers Smart Terminal:

    Figure 20: The Brake tab

  • 8/2/2019 Bell GettingStarted

    23/94

  • 8/2/2019 Bell GettingStarted

    24/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 24

    Notes:

    The MC comman d retu rns the current limit of the drive peak.

    You m ay set the curr ent limits in the Cond uctor wizard as well.

    Refer to t he CL[1],PL[1], and PL[2] com m and s in th e Simp lIQ for Stepp ersComm and Reference Manual.

    3.2 .2 .1 Speed L imi t s

    Use the Limits>Velocity tab in the smart term inal:

    Figure 23: Setting the speed limit s

    In the Speed Limits tab , you can select RPM as the speed un its. For correct

    translation between RPM and sensor counts, you n eed to set th e CA[18]

    param eter (sensor counts p er motor revolution) prop erly. Take care before you

    change CA[18] because if you enter an incorrect value, brushless and stepper

    motors cannot work.

    3 .2 .2 .2 Pos it i on L im i t s

    Open the Protections>Position tab in the smart terminal:

    The position comm and limits apply for open loop stepp er app lications as well asfor position feedback applications. They d o not ap ply to sp eed-only or curren t-

    only ap plications.

  • 8/2/2019 Bell GettingStarted

    25/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 25

    Figure 24: Position command limit s

    Notes: This tab does not set the counting r ange (mod ulo limits). You can define the

    mod ulo limits in the setup w indow of the feedback sensor in the Condu ctor

    Wizard. In an op en loop stepping ap plication the relevant m odu lo limits are

    XM[1],XM[2].

    The comm and limits m ust alw ays be stricter than the feedb ack limit.

    If the comman d limits are beyond the m odu lo limits they will be ignored .

    3.3 Set up t he SensorsThe drive m ay accept tw o sensors. Sensor # 1 is for speed feedback and possibly

    position feedback. The second feedback serves for position feedback, or as a

    sou rce for ECAM.

    To set up the sensor, open th e Condu ctor tool:

    From the Com poser, select the Wizard from the tools menu , or use the Wizard

    button:

    Figure 25: The W iz ard butt on, encircled in red

    This will open the Cond uctor wind ow.

  • 8/2/2019 Bell GettingStarted

    26/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 26

    3.3 .1 Se t t ing up Sensor # 1

    Skip th is section for open loop stepp er app lications.

    Figure 26: Sensor #1 tuning w indow

    Select the typ e of mo tion sensor # 1.

    For a d etailed explanation of each of th e fields in th e tab, click th e H elp bu tton.

    If the motor is small and you can m ove it by hand , you can observe that the

    position read out behaves correctly either by observing the online p osition

    disp lay, or by taking a record.

    Setting up Sensor #2

    You n eed to set u p sensor #2 if you are going to u se it for load feedback, ECAM,

    or as PWM inpu t.

  • 8/2/2019 Bell GettingStarted

    27/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 27

    Figure 27: Sensor #2 setup

    Sensor #2 can also be configured as a PWM inp ut, or as a PWM ou tpu t refer to

    the online help.

    3 . 4 Tun i ng t he D r i v e t o t he Mo t o r

    The next step is to d efine the m otor typ e. After this step, the d igital curr ent

    control of the m otor w ill work, at least at the basic level.

    The motor tu ning w ill not be comp lete after this stage. Additional stages are

    required, as will be explained, before going to the final fine tun ing.

  • 8/2/2019 Bell GettingStarted

    28/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 28

    3.4 .1 Se lect in g th e Moto r Type

    The Simp lIQ d rive can drive DC, 2-ph ase steppers, or bru shless motors.

    Notes:

    Check that th e m otor leads ar e connected correctly. DC motors connect between

    M1 and M2. Bru shless 3-ph ase motors connect betw een M1, M2, and M3, the

    ph ase order d oes not matter. Stepp ers connect one phase between M1 and M2,

    and the other phase between M3 and M4.

    You d o not need to kn ow an y of the motor param eters (resistance, indu ctance,

    torqu e sensitivity, etc.) in ad van ce.

    You p robably do n ot need to ed it the curr ent limiting values, as this was don e

    at the p rotections stage.

    Figure 28: Selecting the motor type

  • 8/2/2019 Bell GettingStarted

    29/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 29

    3.4 .2 Tun ing o r Check ing the Cur r en t Con t ro l

    In the same w indow , select the au tomatic curren t control tool.

    Figure 29:Entering the current cont rol tun er

    The following w indow opens:

    Figure 30: Current tuning w indow

    In general, you d o not h ave to change anyth ing in this w indow , just clickStart.

    When tu ning is over, you w ill see a graph of the resulting current controller

    response.

  • 8/2/2019 Bell GettingStarted

    30/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 30

    By clicking t he frequency grap h b utton , you can also see the frequency response

    of both the open and closed current controller.

    Notes:

    Setting greater phase m argins redu ces overshoot, but it also reduces theband wid th of the resulting curr ent loop.

    App ly the low -pass filter only if the current control is very noisy (this is very

    rare).

    Use greater curr ent levels if you su spect the motor is w orking near m agnetic

    saturation.

    Un-checking Measure all phases will result in shorter, bu t less accurate current

    control tun ing.

    3 . 5 Commut a t i on

    Comm utation tu ning mean s the process of:

    Defining wh ich rotation d irection is positive (this is a subjective user d ecision).

    Learning the ord er and th e polarity at wh ich the m otor phases were connected.

    Learning th e order an d the p olarity of the H all sensors (if present).

    Adjusting the p arameters of the initial rotor position find ing this is essential

    for a brushless motor to rotate.

    Click th e Commutation tab:

  • 8/2/2019 Bell GettingStarted

    31/94

  • 8/2/2019 Bell GettingStarted

    32/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 32

    CheckReset Commu tation Every Hall Edge if your p osition sensor is n ot

    mou nted d irectly on the motor, but throu gh a gear train or a backlash.

    3 .6 Mot i on Tun in g

    This step d epends up on the drive method you choose.

    3.6 .1 Torqu e Dr ive

    If you w ant to enh ance the torque control smoothn ess and performan ce, you m ay

    wan t cogging and speed corrections. For that you will need to tu ne a speed

    controller (even th ough you will disable it later). After tun ing the sp eed

    controller, go to the Fine Tun e tab, finish the fine tun ing, and th en back to the

    Motion tab to select Torqu e control .

    If you d o not need to enhance the torque control, go to the Database tab and save

    your w ork. Then exit the Condu ctor.

    Figure 33:Mot io n t ab fo r t orque drives

  • 8/2/2019 Bell GettingStarted

    33/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 33

    3.6 .2 Stepper Dr i ves w i th no Com m ut a t ion Sensor

    For stepp er dr ives, click the Motion tab and select either Op en loop stepper or

    Closed loop stepp er with sensor #1.

    Figure 34:Mot ion tab

    Here you need to enter the hold ing torque comp onent (static torque, speed

    dep endent torqu e, and accelerating torque).

    The Motor Calculator button helps you to find the required parameters.

  • 8/2/2019 Bell GettingStarted

    34/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 34

    Motor calculator tool

    Figure 35: Mot ion tab for stepper

    After opening t he Motor Calculator tool the following w indow app ears:

  • 8/2/2019 Bell GettingStarted

    35/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 35

    Figure 36: Mot or calculation w indow

    Complete the Inputs section of the form from the motor data sheet; then click

    Calculate . This will give the hold ing torqu e fixed, speed d epend ent, and

    acceleration d epend ent comp onents, and also the maximu m deceleration SD for

    further explanations click the H elp butt on.

    For closed loop position control, this calculator also obtains th e d ynam ic torque

    limit PF[29].

    You can d own load the calculated p arameters to the d rive by clicking Download .

    3.6.3 Speed and Pos i t io n Cont ro l

    This section d escribes the speed and position control loop closure w ide view. The

    details are also d escribed.

    There are three options that lead to ap proximately the same setup actions:

    Speed control with sensor #1.

    Position and speed control with sensor # 1.

    Speed control on sensor #1 and position control with sensor #2.

    Select one and the Motion tab app ears as follows:

  • 8/2/2019 Bell GettingStarted

    36/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 36

    Figure 37:Mot ion tab fo r clos ed lo op con t rol

    The Cond uctor presents an adv anced set of motion tu ning tools.

    The usage level for the tools can be any thing from novice to control expert.

    Before using the Motion tab read the following sections.

    The process is d ivided into several steps:

    Prepare for identification.

    Identification.

    Design.

    Verification.

    This division is because the pr ocess may be iterative in w hich case you m ay need

    to repeat som e of the steps.

  • 8/2/2019 Bell GettingStarted

    37/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 37

    Notes:

    This step assum es that you have pr operly set the curren t control and th e

    commu tation in adva nce. If the current control or comm utation are not

    optim um , the controller tuning w ill yield p oor results. If you use an alog sensor s (Analog encod er, Resolver, Potentiom eter, LVDT, etc.)

    take extra care to ensu re you r p osition signals are clean before you start motion.

    The sensor quality mu st be tested w ith the m otor fully powered , since RFI from

    the m otor occasionally d isturbs the sensor quality. To find th e sensor qu ality,

    open the Com poser, set UM=3 (Open loop ), set HT[1]=CL[1] (maxim um

    holding torq ue), and record th e motion sensor Position and Speed. (The

    distu rbance display on the speed record is m uch clearer than on the position

    record).

    3 .6 .3 .1 Prepa re fo r I den t i f i ca t i on

    The control tun ing environm ent needs a w orking closed loop to start from. The

    initial closed loop d oes not need h igh p erforman ce.

    Allow the Cond uctor to find a controller au tomatically. The Condu ctor tries to

    follow th e guid elines of the Append ix on manu al tuning automatically. It concludes

    with a controller that has quite low performan ce only enoug h to continue

    autom atic tun ing from h ere.

    On starting th e Controller tool, the following w indow opens:

  • 8/2/2019 Bell GettingStarted

    38/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 38

    Figure 38: Start step designer w indow

    ClickStart and wait for the Cond uctor. Usually it succeeds and y ou hav e

    completed th e process.

    If it failed, u se the controls and read th e online help in ord er to obtain a w orking

    starting controller.

    The starting controller replaces the motion controller with a low-performan ce fixed controller. If you h ad a good controller in th e d rive before

    starting the p rocess of finding a controller, save your w ork (using th e Database

    tab) before opening th is window .

    3 .6 .3 .2 I den t i f i ca t i on

    Iden tification is the process of finding the tran sfer function of the controlled

    plant. The transfer function will serve you later when y ou d esign a controller to

    match it.

  • 8/2/2019 Bell GettingStarted

    39/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 39

    The meth od for findin g the tran sfer fun ction is simp le: inject sine signals of

    varying frequency to the plant and m easure the resulting m otion. The

    imp lementation of this method by the Cond uctor, however, is quite complex.

    The transfer fun ction of motion systems d epend s on the signal amplitud e and the

    work ing cond itions. You can log d iffering tr ansfer fun ctions, identified withdifferent working conditions, and then u se them all in a combined design p rocess

    to generate a controller that fits them all.

    For qu ick identification, select the Identify tool.

    The following w indow opens:

    Figure 39:Id ent if ica t io n w in dow

    ClickRu n , answer Yes to confirm the change of control param eters, and wait

    un til completion. The noises you hear are the frequen cies that run throu gh you r

    plant.

    You will receive an id entification result w ith a frequency respon se plot:

  • 8/2/2019 Bell GettingStarted

    40/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 40

    Figure 40:Exam pl e of a frequ ency respo ns e

    ClickOK to return t o the main id entification screen, then save your wor k using

    the File>Save men u. Nam e it MyFirstIden.idn .

    3.6 .3 .3 Des ign

    With th e identification r esults you can design a controller. The controller h as to

    meet th e following goals:

    The robustness figures of merit: acceptable gain and ph ase margins.

    Maximize crossover frequency and low frequency gain for agile and accurate

    control.

    Minimize high frequency respon se, in order to attenu ate noises and in order to

    de-sensitize the controller to th e large u ncertainties of high frequen cyidentification.

    These is a conflict betw een these goals so there is a tra de off.The design

    environm ent of the cond uctor is built to optim ize this trade off.

    Examp le: a comp letely autom atic design: Select the Design tool.

    Select th e Plant tab an d clickAd d . Select MyFirstIden .idn as the iden tification

    file. The following w indow opens:

  • 8/2/2019 Bell GettingStarted

    41/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 41

    Figure 41:Add id ent ifi ed pl an t to the designer

    Select Tools>Automatic d esign .

    The following w indow opens:

  • 8/2/2019 Bell GettingStarted

    42/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 42

    Figure 42:A ut om at ic design w in dow

    ClickRu n . The results app ear in the following w indow :

    Figure 43: Compl ete design

  • 8/2/2019 Bell GettingStarted

    43/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 43

    You h ave now comp leted you r first successful design . You can sav e it to a file.

    Select Tools>Download Design , and in the following wind ow:

    select the Position un it mod e.

    3.6 .3 .4 Ver i f i ca t ion

    In the verification stage simp ly run step responses and jud ge them accord ing to

    your needs.

    Click the Verification tool.

    The following w indow opens:

  • 8/2/2019 Bell GettingStarted

    44/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 44

    Figure 44: Verification w indow

    ClickStart, and th e results appear in the following w indow :

  • 8/2/2019 Bell GettingStarted

    45/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 45

    Figure 45: Controller verification results

    3.7 Fine Tun ing

    The Fine Tuning tab enables special enhancements to be tu ned . This is not

    required for all applications.

    The following fine tunings are available:

    Cogging compensation

    Analog encoder ind ex tun ing

    3.7.1 Coggi ng Com pensat ion

    The first comp ensation is for cogging . It becom es available when y ou check

    Enable Cogging Comp ensation .

    The cogging comp ensation add s a comp ensation torque )(T where is the

    m otors electrical ang le; The aim of this wind ow is to m ap )(T .

    This map ping can be saved in the d rive, saved to a file, or retrieved from a file.

  • 8/2/2019 Bell GettingStarted

    46/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 46

    Figure 46: The Fine Tunin g Tab

    On op ening the cogging compen sation tool, the following w indow opens:

  • 8/2/2019 Bell GettingStarted

    47/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 47

    Figure 47: Cogging com pensati on tuner w indow

    The following options are available:

    Set the cogging com pen sation to d efault, i.e., there w ill be no coggingcompensation.

    Load a cogging table from a file, withou t m easuring any thing.

    Measure th e actual m otor cogging by clicking Start.

    When starting a cogging measurem ent, the following wind ow op ens:

    When you clickYes , the experimen t starts and th e progress is displayed at the

    bottom of the window .

  • 8/2/2019 Bell GettingStarted

    48/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 48

  • 8/2/2019 Bell GettingStarted

    49/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 49

    3.7.2 Fine Tun ing an Analog Encoder

    If sensor # 1 is set to "Analog incremen tal encoder " in the "Sensor # 1" w ind ow ,

    then t he "Analog ind ex tuning" button is visible. This tuning d efines the signal

    level and position wh ere analog index capture occurs.

    Please note that for analog encoder, the index app ears at d ifferent p ositions for

    forward travel and for reverse travel; both cases are measured.

    Figure 48: The Fine Tuning w indow w hem sensor #1 is an analog encoder

    When you clickAnalog Ind ex Tunin g, you need to d efine the experiment motion

    in the following w indow . The motion h as to traverse the analog encoder ind ex.

  • 8/2/2019 Bell GettingStarted

    50/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 50

    Figure 49:Ana lo g ind ex t un in g

    After you set the p aram eters for th e experiment, clickStart to begin; progr ess is

    displayed in the progress bar at the bottom of the window .

  • 8/2/2019 Bell GettingStarted

    51/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 51

    3.8 Database Main t enance

    Finally, save the resu lts. Click the Database tab:

    Figure 50:Da tabas e m ai nt ena nce t ab

    Check the d ataba se integrity. This checks for certain conflicts that can p reven t

    the m otor from starting. For examp le, if you selected a comm utation finding

    method by CA[17] that d oes not m atch the installed sensors, the motor w ill not

    start and it will report "Bad Database". Checking th e datab ase here will prevent

    this error.

    Save your p arameters in flash mem ory.

    Restore your previously stored par ameters from flash memor y if you w ant to

    pu rge your Condu ctor session.

    The Expert List of this window brings up the entire Simp lIQ d atabase.

  • 8/2/2019 Bell GettingStarted

    52/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 52

    Chapt e r 4 : Advanced Cont r o l Tun ing This chap ter is intend ed for users w ishing to u se the extra flexibility of the

    motion control tu ning system beyon d the "getting started" level.

    This chap ter assum es you are familiar w ith Section 3.6.3.

    Feedback d esign is a four-step p rocedu re.

    The first step is to generate a low p erform ance controller that is called the

    "starting step con troller".

    This minimal controller only has to stabilize the m otor w hile the plant d ynam ics

    are identified. The Getting Started chapter, together with th e Manual Tuning

    App end ix, covers this step.

    The second step is to identify the plant mod el, that is, to find its transfer

    function; amplitud e-ph ase versus frequency. Several frequen cy responsemeasu rements can d escribe the same plant in ord er to reflect plant u ncertainty.

    The third step is to design a controller to match th e plant's frequency response.

    The user orients the design optimization by emp hasizing design margins,

    bandw idth, or noise attenuation.

    The fourth step is verification run ning a 'field' evalua tion test.

    Notes:

    The "Getting Started" chapter h as taken you throu gh all these stages, choosing

    full automation. This chap ter goes over the tun er options in greater d etail.

    The feedback design p rocess may be iterative you can return to the d esignstage to impr ove on th e test results, or you can return to the identification stage

    to add the results of new w orking points.

    The auto-tuner is very flexible regarding th ese steps, as explained in t he

    follow ing sections.

    4.1 Star t Step Cont ro l

    4 . 2 I den t i f i ca t i on

    This chap ter deals with id entifying the p lant includ ing, its uncertainty.

    Notes:

    This Chapter focuses on und erstanding w hat you d o rather than on detailed

    explanations of the w indow controls.

    Detailed explanations of the wind ow controls are in the online help.

    The wind ow controls may d iffer between Cond uctor versions, so the

    explanations given here m ay also vary slightly.

  • 8/2/2019 Bell GettingStarted

    53/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 53

    4 . 2 .1 I den t i f i ca t i on and Unce r t a i n t y

    The identification p rodu ces a frequency respon se. A frequency respon se is a

    characteristic of a linear, time invariant plant. We take frequency respon se not

    because the plant is really linear and time invariant; but because all the

    established control design theory d eals with p lants having frequency responses.

    Knowing very w ell the limitations of frequency responses, the DFT tuner

    identifies man y frequency responses instead of one. Each frequency response

    describes the plant linearized about a d ifferent w orking point.

    After this process, you w ill have many m easured values for the amp litud e/ phase

    of the plant at any given frequency. This set of values forms an "un certainty set"

    for the frequency.

    Later, the Cond uctor w ill design a controller that op timizes the response to the

    entire uncertainty set. This is much better than trad itional m ethods th at can only

    consider one p lant mod el at a time.

    When the Cond uctor presents the identification result it normally shows one

    nom inal transfer function. This is because han dling a mu ltitude of transfer

    functions is very comp lex.

    Identification is an involved process, as it is nonlinear an d noisy.

    The Condu ctor is based on man y years of trials and collecting d ata from actual

    motion systems.

    4.2 .2 I den t i f i cat ion Resu l t s ManagementThe Condu ctor stores the identification results in files with th e .idn extension.

    An identification file stores a list of frequencies and the associated amp litud e and

    ph ase values of the p lant transfer fun ction.

    You can keep several .idn files, each d escribing the p lant w ith d ifferent w orking

    conditions.

    Identification file maintenance is from the w indow that opens b y clicking

    Identify in the Motion tab of the Cond uctor.

  • 8/2/2019 Bell GettingStarted

    54/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 54

    New

    OpenSave

    Cleanup

    Figure 51:Iden t if icat io n fi le mai nt enan ce opt io ns

    You can r eset the iden tification p rocess (New ) and store results (Save).

    You can also ed it existing id entification resu lts.

    You can ad d frequency points to an existing identification. Op en an existing

    file, then ad d the frequencies you w ant (furth er details app ear later in this

    man ual). This mean s that if you w ant to ad d d ata in a certain frequency region

    you d o not need t o go throu gh th e entire identification p rocess.

    You can clean outliers from frequency respon ses (Cleanup) deleting an

    identified frequency w hich you consider un reliable

    4 . 2 .3 I den t i f i ca t i on Work Po in t

    Identification is th e art of exciting the p lant w ith signals, so that its respon se will

    reveal the most about its nature.

    The Condu ctor identifies frequency respon ses, thu s it natu rally selects sinusoidal

    excitation. App lying pu re sinusoidal excitation in an op en loop m ay not be su cha good idea the motor may d rift away and high frequency data m ay be

    completely obscured by frictions.

    The Condu ctor uses the "Starting Step" controller to set the p lant w orking p oint;

    at this w orking p oint it app lies the sinu soidal exciting signals.

    You need to help th e Cond uctor in selecting the id entification w ork-point, from

    the following options:

    Stay in p lace: The start step controllers hold the m otor m ore or less in a fixed

    position. The m otor w ill har d ly dr ift; the id entification w ill suffer from

    frictions.

  • 8/2/2019 Bell GettingStarted

    55/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 55

    Free: For non-restricted displacement arou nd the initial position. The starting

    step controller w ill keep the m otor w ith constant speed , so that the frictions w ill

    m inim ally affect identification. This mod e gives the best linear id entification.

    Bounded: For restricted d isplacement arou nd the initial position w ith given

    position limits aroun d the initial position. This mod e gives most of the Free

    mod e advantag es when you cannot allow free rotation of the motor.

    You can id entify in each of the "Stay in p lace", "Free" or "Bound ed" m odes.

    The comp arison will inform you how frictions affect you r system; and the later

    control design m ay consider all the cases.

    The following figure show s you r selection. The w indow opens by clicking

    Identify in the Motion tab of the Cond uctor.

    Figure 52: Selecting the identification method

    CheckIden tify Aux. Sensor if you intend to use sensor # 2 for position control.

    4.2 .4 Se lect in g th e I den t i f i cat ion Frequenc ies

    The Condu ctor applies sine signals to the plant. Each sine signal mu st be

    maintained long enough for the transients to disappear, then the Condu ctor can

    extract th e frequency response for th at single frequency.

    Putting so mu ch energy in a single frequency gives the best results which are also

    the m ost noise imm un e. However, the identification is slow.

    The Condu ctor mu st select the identification frequency with care, so that:

    It will find all the critical plant d ata, withou t m issing imp ortant p oints.

    It can com plete the identification in a reason able time.

    The Condu ctor applies an iterative search w hich first spans a broad set of

    frequencies.Where th e frequ ency respon se looks locally sm ooth , it accepts it.

    Where it finds large am plitud e or ph ase gradients, it applies denser frequencies.

  • 8/2/2019 Bell GettingStarted

    56/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 56

    Although the autom ated frequency search w orks well in m ost cases, the

    Cond uctor may miss very narrow resonance/ anti-resonance pairs.

    We recomm end th at you first let the Condu ctor ident ify with au tomated

    frequency search.

    CheckAutomatic Refinemen t to allow intensified resolution wh ere the

    frequency respon se changes rap idly, e.g. near resonant m odes.

    Make manual adjustments when:

    The identification results do not look continu ous and smooth enou gh.

    You su spect, based on th e evaluation results, that th e Condu ctor missed a

    resonance.

    For this purp ose, use the Frequency Editor.

    Figure 53: Selecti ng the frequency edit or

    If you open the Frequency Editor before you have an identification resu lt, the

    wind ow looks like this:

  • 8/2/2019 Bell GettingStarted

    57/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 57

    Figure 54: Frequency Edit or, w hen no identif ication is av ailable

    The red p oints, and t he list in the Frequency area, show th e frequen cies for p lantexcitation. For every frequ ency there is also an associated excitemen t curren t

    amplitude.

    Before the ident ification you can see the defau lt set of frequen cies that th e

    Cond uctor sets before learning the plant.

    Bigger curr ent am plitud es generate a better signal to noise ratio, and are thu s

    better for identification. There are other considerations, however:

    o Large curren ts at high frequencies tend to saturate th e amp lifier voltage

    du e to m otor ind uctance. This saturat ion is reflected in the id entified

    transfer function by decreased amp litude and increased d elay.

    o Large curren t near resonant m odes lead to u np leasant noises, or even

    mechanical damage.

    After clicking Run Iden tification the wind ow ap pears as follows:

  • 8/2/2019 Bell GettingStarted

    58/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 58

    Figure 55: Frequency editor w indow after identification

    The blue points sh ow identification resu lts.

    There are no red points an d no p oint listing in the selection box since all the

    frequen cy points have been run and there has not yet been a new requ est.

    You can add and edit new frequency points and r un th em; their identification

    result will be app ended to the existing frequency respon se results.

    For the above identification, the resolution seems poor near th e anti resonance

    and near th e 2-3-4 resonances. We wou ld like to increase the resolution there, and

    use the Add>Graphics tool.

    Add the red frequency p oints to the grap h; on the next "Run Identification" onlythe frequencies you ad ded will be iden tified, and ap pend ed to the existing

    identification record.

    Notes:

    Poor resolution u sually reflects in the p hase wind ow being clearer than in the

    amplitude window.

    Do not confuse 360 ph ase jum ps with p hase resolution problems. Phase jum ps

    of 360 (see the right end of the above p hase p lot) come from angle d isplay

    folding.

  • 8/2/2019 Bell GettingStarted

    59/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 59

    Figure 56: The Frequency Editor

  • 8/2/2019 Bell GettingStarted

    60/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 60

    Append ix A : Manua l Tun ing o f Speed

    and Posi t i on Con t ro l

    A.1 ScopeThis Append ix explains how to man ually tun e controllers of the following t ypes:

    1. A PI speed controller.

    2. Cascaded position controller: The inner loop is a PI speed controller and the ou ter

    loop is a p osition sim ple gain controller.

    3. A PI speed controller w ith a single notch filter, a low-pass filter or both .

    4. Cascaded position: The inner loop is a PI speed controller w ith a single notch filter,

    a low-pass filter or both; and the ou ter loop is a simple gain.

    The notch filter and / or low-pass filter are termed in th is documen t as "High

    ord er filters".High order filters are expected to im prove closed loop p erforman ce

    if the sensors are noisy with systems th at exhibit resonance, and wh en it isessential to d ecrease high frequency m otor currents. The H igh ord er filter can

    imp rove the controller p erforman ce dram atically when used correctly. Incorrect

    usage of the H igh ord er filter can lead to a poor or even un stable controller.

    Use the manu al tuning as a starting point for autom atic tun ing: Autom atic tun ing

    brings better results than hu man tun ing in most cases.

    Notes:

    This app endix concentrates on man ual tun ing tips and theory, and it does not

    prov ide an accurate description of controller p aram eterization. For that, refer tothe KP[N], KI[N] comm and s etc in the SimplIQ for Stepp ers Comm and

    Reference Manual. All the relevant comm and s hav e links to the full control

    structure description.

    This appen dix d oes not d escribe the tu ning int erfaces see the sections on

    motion tun ing for that.

    We strongly recomm end familiarizing yourself with the controller structur e and

    param eterization before attemp ting to tune it.

    A.2 Safety

    Servo systems mu st be treated w ith care. In the tu ning p rocess, they mu st be

    treated w ith extreme care. Although we hav e mad e our best efforts to generate

    safe tun ing conditions:

    In the tu ning p rocess, the motion controller m ay become un stable, leading to an

    abrupt, unexpected response.

    In the tun ing p rocess, the m otion controller may become very w eak, letting

    distur bances and external loads d rive the shaft.

    Read this app end ix carefully before launching an experiment, and evaluate the

    experiment p aram eters carefully before laun ching it. The Cond uctor sug gests

    some experiment par ameters, but it may mislead you, being u naw are of yourspecific limitations.

  • 8/2/2019 Bell GettingStarted

    61/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 61

    Treat un balanced1

    systems w ith extreme care.

    A.3 Make i t Sim p le

    This Append ix gives some simp le guidelines for m anu al controller tuning. In

    ord er to simp lify the tu ning p rocess we d ivide it into a series of steps.

    The ru les of simp lification are:

    Never tu ne your controller to perform better than you need. A controller of

    lower band wid th d ecreases stresses and is more robu st to changes and ageing.

    In this Append ix you w ill learn how th e High ord er filter may decrease control

    stresses.

    Tuning a speed controller is simpler than tun ing a p osition controller. If you

    need to tu ne a position controller, try to tu ne first its emb edd ed speed

    controller. The Condu ctor program lets you tu ne a speed controller withou t the

    risk that the m otor w ill drift away from its starting shaft position.

    If your m echanics are simp le and good enough to avoid the H igh order filter,

    adh ere to the simp le PI speed controller. The High ord er filter requires more

    skill to u se. The H igh ord er filter always introdu ces a filtering d elay, which

    usu ally limits the achievable band wid th compar ed to a simple PI.

    Use the High ord er filter when en countering oscillations and high frequency

    noise. The sm all extra effort of tun ing the High or der filter can be very

    beneficial.

    If your en coder has good enou gh resolution and the friction is low enough , use

    a fixed cont roller.

    Use controller sched uling (dynam ic adap tation of the controller param eters tothe situation) if you h ave a low -resolution encoder or high friction. The extra

    effort of tun ing th e High ord er filter can be very ben eficial.

    Work linearly. With high controller gains the curren t comm and saturates for

    very sm all tracking errors. The saturation m akes the evaluation of control

    quality very d ifficult. Keep th e motions sm all enou gh an d verify by th e current

    wav eforms that th e curr ent comman d d oes not saturate2. Verify how th e

    controller w orks w ith large signals only after it is satisfactory with small

    signals.

    Work w ith steps. When y ou test a controller with limited acceleration or even

    smooth ed reference w aveforms, d on't excite high frequencies. The resu lts willnot reveal oscillations and high frequency p roblems that may exist.

    Do not fear oversh oots. Overshoots are necessary if the controller is to track

    withou t a time d elay. Redu cing th e height of the overshoots lengthen s their

    du ration. Evaluate the overshoot that y ou can tolerate by experimen ting with

    acceleration limited test waveforms, without exceeding the acceleration you

    actually u se.

    1Systems that do not stay in place when the motor is shut down.

    2 Note that the rate of change of the current command is also limited. This is because

    LVdtdImaxB= where I is the motor current, BV is the supply voltage and L is the motor

    inductance.

  • 8/2/2019 Bell GettingStarted

    62/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 62

    A.4 Keep Marg in s

    It is very temp ting to increase the controller gains and enjoy the m aximal

    performan ce of your system. You m ust bear in m ind th at the price of maximu m

    performan ce is decreased robustn ess to system variations. The higher the gains, the

    greater the chance that the system w ill become n oisy or even unstable d ue tochanging w ork conditions, or du e to ageing. The following tips w ill help you create

    a stable, long-lasting m otion system:

    Tune for m inimu m inertia. If the inertia of the system varies, e.g. for a rotary

    robot arm , tune for minimal inertia3. Positions or loading conditions with

    higher inertia w ill have a slow er response time, but are likely to remain stable.

    The controller must rem ain stable (it does not h ave to maintain an op timu m

    response) when you dou ble the selected gains, and also when th e selected gains

    are redu ced by half4.

    Acceleration limits. For a position controller, the maximum motor acceleration

    (parameter GS[9]) mu st be set high enou gh so that it does not d isturb norm aloperation, but also low en ough so that it prevents p osition d isturbances from

    creating large overshoots.

    A.5 The Bas ic Con cept s

    This section concisely and inform ally explain s the entities you w ill come across

    when tuning.

    A.5.1 Fixed - vs . Gain-schedu led Cont ro l l e rs

    The drive can ru n either a fixed - or a gain-sched uled con troller. A fixed contr ollerrun s a fixed set of control param eters

    5.

    Gain scheduling is the p rocess of adap ting the controller param eters "on th e fly"

    to a given situ ation. The Drive stores 16 sets of contr oller param eter sets. The

    active controller p aram eters set is chosen by the gain sched uling p rocess.

    The drive supp orts two typ es of gain sched uling.

    Autom atic gain scheduling: the Drive adap ts the controller to the speed

    controller comm and , in real-time. The reasons for au tomatic gain schedu ling

    are:

    o When th e speed becomes low, there is a large delay between consecutive

    encoder position u pd ates. This delay requires a decreased controller

    bandwidth.

    o At low sp eeds friction becomes a dom inant control pr oblem. Increasing

    the integrator gain at low speeds m ay improve low speed behavior.

    3 Tuning for the least inertia may have a high price with high inertia postures or load conditions. You

    can tune instead for several postures or loads and apply manual gain scheduling.4

    If you tune a speed controller you don't have to test with halved gains. Position controllers are,however, conditionally stable. This means that a position controller will loose stability with gains that

    are small enough.5The fixed/scheduled option refers to the proportional and the integral speed gains, position gain, and

    some parameters of the Advanced filter.

  • 8/2/2019 Bell GettingStarted

    63/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 63

    Manu al gain schedu ling: The controller param eters may adap t du e to a user

    program or an external comman d . For example, the controller gains of a wind er

    may be increased as it rolls and gains w eight.

    For convenience, wh en you p rogram a fixed controller you d on't overwr ite the

    schedulable param eters, and vice versa.

    The Au to-tun er always programs an au tomatically gain-sched uled controller.

    A.5.2 Resonance and Notch Fi l t e rs

    Resonance is a very comm on m echanical phen omenon , in w hich a flexible system

    vibrates in its natu ral frequencies. In man y ap plications, the natu ral frequencies

    are too h igh for the m otion controller to control. The best policy for the m otion

    controller is then to a void exciting the oscillations. You chain a ba nd -stop (notch)

    filter to the controller to p revent th e controller from d riving the oscillatory

    frequency.

    If you d on't u se a notch filter wh ere necessary, either:

    Severely limit th e possible controller band wid th.

    Risk instability an d extreme stresses to th e controlled system.

    Tips:

    Norm ally there is m ore than one resonance frequen cy. It may be n ecessary to

    set more than a single notch.

    In some systems th e resonance frequency changes significantly d ue to load or

    postu re changes. Verify that you r d esigned notch covers the entire operational

    envelope.

    A.5 .3 H igh Frequency No ise and Low -pass Fi l t e rs

    High frequen cy noise mean s vibration, acoustically un acceptable noise, and

    mu ch greater pow er consum ption than is necessary just to d rive the motor to its

    desired sh aft position. The main r easons for high frequency noises are:

    Sensor in accur acy.

    Plays or backlash in the mechanics.

    High frequency, unid entified resonance, possibly du e to aliasing6.

    The best policy for the m otion controller is to avoid exciting the m otor at a high

    frequency because th e system v ibrates there or because the feedback is not

    reliable. For this pu rp ose chain a low -pass filter to the controller.

    The pr ice of a low-pass filter is an equivalent d elay. For a d ouble pole filter w ith

    a d amp ing factor of 0.7, the insertion d elay is about 0.23/ f, wh ere f is the corner

    frequency.

    6

    We deal with a sampled system. High frequency signals may appear to sampled systems in changed,low frequencies. For example, if the Drive samples at 300 usec (TS=75), then an oscillation with a

    period of 300 usec (3333 Hz) appears to the Drive as a constant value (frequency=0).

  • 8/2/2019 Bell GettingStarted

    64/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 64

    A.5.4 Eva luat ing a Step Respon se R ise Tim e, Set t l ing

    T im e, and Overshoo t .

    A step respon se is the w aveform (position or sp eed) the motor exhibits when its

    reference comm and (position or speed) changes abru ptly. Step resp onses are not

    very p ractical in real-life m otoring ap plications, as the reference comm and s arenearly always acceleration limited and man y times smoothed .

    A step respon se is, however, good to r eveal the detailed dyn amic behavior of the

    controller. The m ost pop ular step -respon se figures of m erit are:

    Rise time: The tim e since the reference has been chan ged u ntil the valu e

    (position or sp eed) covers 90% of the step .

    Settling tim e: The tim e since the reference has b een changed un til the value

    (position or sp eed) remains perm anently w ithin 3% of the step.

    Overshoot: The percentage of the deviation to the oth er side w hile stabilizing

    the step.

    These figures of merit are show n in Figure 57.

    0.011 0.012 0.046 0.050 0.0740

    200

    400

    600

    800

    1000

    1200

    1400

    Target

    Time

    Figure 57:A st ep respo ns e: The rise t im e is abou t 0.01, t he set t li ng t im e is 0.074, an d the

    overshoot is about 30%.

    The overshoot level, as well as the ratio between th e rise time an d the settling tim e,

    reflect the gain and the ph ase margins7. Gain or p hase margin resu lts that are too

    low m ay result in a high step response overshoot (more th an 40%) followed by an

    un dershoot and a long settling tim e. If the phase m argin is too high, the settling time

    is too long. These prop erties are d epicted in Figure 58 below w hich is a simu lation

    of three design examp les: One w ith reasonable margins, one w ith margins that ar e

    too low and one with ph ase margins that are too high.

    7The gain margin is the factor in which the controller gain can be increased until loosing stability. The

    phase margin is the difference of the open-loop phase from -180 degrees at the point where the open-

  • 8/2/2019 Bell GettingStarted

    65/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 65

    0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.080

    2000

    4000

    6000

    8000

    10000

    12000

    14000

    16000

    Time (sec.)

    Stepresponse

    Accep table margins: Nice response

    Too low margins: large overshoot and oscillations

    Too much margins: long settling time

    Reference

    Figure 58: Comparison bet w een st ep responses of acceptable controllers and non-

    acceptable controllers. Details on t he plot.

    A.6 The Exam ple Sys tem

    Manu al tun ing is not a true science with closed formulas. It is heur istic, and theheu ristics fit only a (relatively w ide) selection of systems. All the explanat ions in

    the rest of this Append ix refer to the tw o laboratory systems, shown b elow.

    Both the systems hav e the same motor and amp lifier:

    Characteristic Value

    Motor type Brush less, three pole pairs, 4 Amp continu ous.

    Encoder resolut ion 4000 coun ts/ rev (1000 lines)

    Am plifier Bell 5/ 100

    In system # 1, the m otor is loaded by a simp le inertia. This simp le inertia loadenables high band wid th control. In system #2, the load inertia is coup led to the

    motor throu gh flexible coup ling. The coupling introd uces a mechanical

    resonance.

    loopgain is 0 db. For further explanation, see the Auto-tuning manual, or any basic textbook in controltheory.

    Acceptable margins: good responseMargins too low: large overshoot and oscillationsMargins too high: long settling timeReference

  • 8/2/2019 Bell GettingStarted

    66/94

    The SimplI Q for Steppers Gett ing Start ed & Tuning and Comm issioning GuideMAN-BELGS (Ver. 1.1) 66

    A.7 Tes t ing t he Respon se o f a Cont ro l le r

    Manu al tuning is an iterative process in w hich you select param eters for the

    controller, and then test them .

    A.7 .1 Cur r en t L im i t s

    Beware that th e peak current limit and the continuou s curren t limit of the dr ive

    may differ. If you u se excessive current levels in the experiment, the d rive may

    switch autom atically to the continu ous limit, and exhibit saturation b ehavior.

    A.7 .2 Record in g the Exper im ent Resu l t s

    The Condu ctor's Wizard records the resu lts of the tu ning experiment. The

    recorder is autom atically triggered wh en the motion comm and (speed or target

    position) changes.

    The record er records th e reference and the actual speed an d position waveforms,

    and also the motor's current d emand . The current dem and is very useful for:

    Detecting saturation. If the current d emand is saturated th en the system

    reached ph ysical limitations, and you cannot distinguish th e small signal

    response from the experiment result.

    Current comm and wav eforms easily reveal ph enomena like friction (curr ent

    increases for a wh ile before the motor starts to m ove), cogging (period ic-in-

    position torqu e distur bance), dyn amic un balance (periodic-in-position torqu e

    distur bance, prop ortional to the squared speed), play (the ratio between current

    and acceleration jumps wildly), resonant limit cycle (constant frequencysinusoidal disturban ce) and m uch more.

    Large high frequency current d eman ds reveal the need for high frequency

    filtering in a m ore vivid way th an p osition or sp eed error.

    Check that the currents are near th e expected v alues for the accelerations used .

    This gives you extra assuran ce that the system is prop erly assembled an d w ell

    calculated.

    You can set the recorder time as long as you wan t, but for large recording times

    you w ill lose resolution, as