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Glass International December/January 2014

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Process control systems for batchhouse control

The use of sophisticated automation technology is an important aspectof a high quality batch house installation. The Siemens PCS7 processcontrol system and the Totally Integrated Automation (TIA) conceptprovide a platform for an integrated control concept for completeinstallations. Roger Knüttel and Holger Hass* discuss the benefits of thetechnology for batch house plants.

Not all systems marketed under

the PCS7 name are really what

they claim to be. Certain

suppliers actually exit the PCS7

environment and transfer the system

intelligence for weighing and dosing to

external weighing processors that are

definitely not PCS7 compliant. EME

systems do not fall into this category.

PCS7 in the glass industryPCS7 has been used successfully for

automation of the melting process and

other equipment in the glass industry

for many years. However, the batch

house represents an unusual case.

The processes are typical batch-based

ones, but standard components such as

Simatic Batch or PM Batch from Siemens

are rarely, if ever, used.

A typical solution involves the use of

proprietary hardware in the form of

external weighing processors to carry

out the core functions of the batching

process, together with a PCS7 system for

sequence control.

This arrangement does not make any

use of the extensive capabilities and

advantages of the PCS7 system as the

complex intelligence required for the

process is embedded in external units.

EME has adopted a different strategy

for many years. Since the middle of the

1990s it has concentrated on an

integrated approach involving all

control components.

This has resulted in two important

developments: Integrated PCS7 control

systems and full web-based operation.

Basic characteristicsThe core of the EME batch house control

concept is a Siemens Simatic S7-400

Programmable Logic Control (PLC)

together with Siemens Siwarex U, FTC or

FTA weighing units. The concept is in

accordance with the basic TIA principles.

The EME system employs modular

hardware and software, so that it is easy

to scale systems up or down to adapt

them exactly to the requirements of

each individual installation.

It is also important that all

components are freely available on the

open market, are also used in other

industries, and have been supported and

further developed by their manufacturer

over a substantial period of time.

EME does not use proprietary

equipment for weighing, so it is easy to

replace these components, even in older

installations. This also allows existing

installations to be updated progressively

and new technology can be introduced

step by step.

Recently, EME has converted a

number of obsolescent control systems

to this up-to-date concept, mainly while

production continued.

The strict modularisation and

standardisation of the EME concept,

together with the continuing

downwards compatibility over

numerous development cycles, offers

the customer a smooth transition during

future upgrades of their system.

The EME visualisation concept offers a

clearly laid-out presentation of all

process steps, coupled with intuitive and

windows-conform operation.

Particular attention is paid to the

production of a visually attractive, but

structured, image of the installation.

Important information is quickly and

easily available to the operator, as is

access to the most important functions.

This has been shown to result in a

significant reduction in operator errors.

The integrated language-change

function means that almost all

important world languages are accessible

(Fig 1).

continued »

� Fig 1 Premix

system.

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Glass International December/January 2014

Batch plant

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The real thingThe EME batch house control system,

already in worldwide use on many batch

house installations, has now been

transported to the PCS7 environment

utilising the capabilities of the PCS7

Advanced Process Library (APL).

As a result EME is the first batch house

supplier worldwide to offer an integrated

PCS7 system (Fig 2).

All components are taken from the

PCS7 range, especially the dosing and

weighing processors, which are at the

heart of any batch house automation

system.

This approach is unique in the glass

industry and represents complete

implementation of the TIA concept.

The combination of the PCS7 web

server and the web-based EME batch

system gives the customer an integrated

system based on standard components

with access to an Enterprise Resource

Planning system (ERP) and intranet.

Web-based access Since 2011 EME has provided facilities

for web-based access to its control

systems using any suitable web browser

and platform. It is only necessary to

install a Windows Terminal Server on

the operator station.

The core of the EME batch system,

based on a Microsoft SQL server, has also

been extended by the addition of a web

server, so that all components are now

fully accessible for operation through a

web browser.

The EME batch house control concept

therefore encompasses two interfaces:

The standard Windows interface and an

additional web interface. Web access is

possible from all types of device, such as

Windows or Linux computers, iPads,

Android tablets and smartphones,

whereby the necessary level of security

must always be maintained (Fig 3).

Recipe managementThe basis for the manufacture of high

quality glass articles is established by the

precision with which the raw materials

are combined to form the glass batch.

Comfortable recipe management is

therefore an important function of the

EME batch house control system. Recipe

management is based on a modern

databank application which can store up

to 10,000 recipes.

Each individual recipe contains all

parameters required for a complete

charge, such as dosing set points,

weights for coarse and fine dosing, run-

on correction, dosing speeds, dosing

power monitor and numerous other

parameters (Fig 4). Each recipe is

provided with a specific destination (e.g.

furnace number, mixer) so that the risk

of contamination is eliminated.

Any recipe change is protocolled and

the data is synchronised on all other PCS

operator stations. The complete

parameter set defines both the product

and the required process path.

When used in combination with the

EME High Performance Batching system,

the arrangement provides clarity of the

process steps required and the transport

of the materials to the correct mixer and

melting furnace.

Analysis of production dataThe charge and consumption analysis

module permits a complete and detailed

analysis of the glass batch production.

The charges produced can be listed on

the basis of melting furnace, recipe or

furnace bunker, whilst tolerances and

out-of-specification charges can also be

called up.

Lists can be made on a daily or

monthly basis, but the selection of a

freely definable time period is also

possible. Other possibilities include the

analysis of individual material

consumption, also based on days,

months or a selected time period.

Dosing accuracy can be determined by

the establishment of a curve chart.

Results can be printed out or stored in

the data bank using the Microsoft SQL

server, which allows large quantities of

data to be handled (Fig 5).

Data exchange with an ERP system

can be done through an Extended

Markup Language (XML) export or by

direct access to the SQL databank. Both

facilities are available as standard. The

structure of the XML export file can be

freely configured using a style sheet.

High performance batchingBatch house installations that must

supply several melting furnaces

simultaneously require a control system

with particular intelligence.

Glass batch charges must be produced

according to a number of different

recipes and be transported to the correct

melting furnace at the required time.

EME has developed the High

Performance Batching system expressly

for this purpose. This system can achieve

optimum glass batch throughput on the

basis of the recipes and charge system,

while maintaining secure operation and

providing maximum transparency of all

process steps.

Transport paths for all raw materials

are clearly defined and the system

ensures that there is no contamination

by remains of other batch compositions.

continued »

� Fig 2 Raw material feed with silo mass balance and Radio Frequency Identification (RFID) with PCS7 APL

connection to a Siwarex FTA material delivery scale.

� Fig 3 Scale calibration using a smartphone.

Adjustment parameter

Base settings

digits empty value 6656

41567

1000

410

300

500

kg

kg

mV2

0,0

digits adjust, weight

adjustment weight

zero setting point

limit zero setting point

unit

load cell characteristic

decimal point

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The complete process sequence for a

charge is optimised so that unnecessary

waiting times are avoided.

Operator access Controlled access and registration of all

personnel using the system are

important basic functions of any control

system. Every user can be provided with,

or denied, detailed access rights in

individual windows. A biometric access

function, such as with finger print

sensors, can be provided. Any and every

change is recorded and stored in a long-

term archive.

High redundancy systemsIf there are particular reasons why a

higher level of operational security is

needed for a batch house, various levels

of redundancy can be introduced,

according to the level of security

required. This can involve the use of

redundant processors (CPUs), bus

system or remote stations.

This type of system has the advantage

that it can continue to operate even if a

component fails.

Traditional back-up solutions with

external weighing processors and

hardware based operation with push

buttons may appear to offer an

acceptable back-up capability.

In reality, however, in the case of a

system failure experience has shown

that a typical operator will quite simply

not be able to cope with the demands of

this type of manual operation resulting

in production disturbance. �

* Roger Knüttel, Manager ControlEngineering DepartmentHolger Hass, Manager ControlEngineering DepartmentEME Maschinenfabrik Erkelenz, ErkelenzGermany

� Fig 4 Active recipe for one scale. � Fig 5 Dosing diagram for a single component.

The FMT24S is a state of the art distributed machine control system. It consists of modules networked with industrial bus systems.Highlights:

servo technology fully integrated · integrated electrical overrides · safe stop functionality via CANopen® · monitoring of valve current control of servo proportional valves · interface to commercial PLC systems · internet technology

For more information: futronic GmbH · Tolnauer Strasse 3-4 · D-88069 Tettnang Tel: +49 7542-5307-0 · Fax: +49 7542-5307-70 · www. futronic.de · info@ futronic.de

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futronic

automation with brain