sop/pd/305 01 standard operating procedure · sop/pd/305_01 standard operating procedure precisa®...

UNIVERSITY OF MALTA

FACULTY OF MEDICINE & SURGERY

PHARMACY DEPARTMENT Ref. No. SOP/PD/305_01

STANDARD OPERATING PROCEDURE

PRECISA® 1600C PRECISION BALANCE

Valid for:

2 years from

approval

of 16

Table of Contents

Page

1. Scope 2

2. Objective 2

3. Definitions 2

4. Responsibility 3

5. Procedure 3

6. Precautions 14

7. References 14

8. Appendices 14

9. Revision History 14

Original

Authorised Copy

for:

Reading Copy

Written by: Signature/Date:

Reviewed by: Signature/Date:

Approved by: Signature/Date:

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1. Scope

This Standard Operating Procedure (SOP) applies to the staff and students

making use of the Precisa® 1600C Precision Balance in the laboratories of the

Pharmacy Department, University of Malta.

2. Objective

To describe the procedure for the installation, configuration, operation,

calibration, maintenance and troubleshooting of the Precisa® 1600C Precision

Balance.

3. Definitions

3.1. Adjustable Feet / Levelling Screws: Two circular screws situated at

the bottom of the balance that are manipulated to level the balance out.

3.2. Calibration: A procedure performed to check a measuring instrument

against an accurate standard to determine any deviations and correct for

errors.

3.4. Configuration Parameters: A number of different options that are

used to set the balance according to the user’s preferences.

3.5. Floating Display: A function that enables the balance to adapt its

integration time to the conditions of the environment.

3.6. Main Menu: Allows the user to adapt the balance to his/her changing

requirements and to any peripheral conditions. It consists of 4 main

options:

Calibration – to carry out the calibration process

Program Second Unit of Mode Key – to choose the unit to be set as

Unit2

Floating Display – to choose the desired time for the floating display, if

being used, i.e. 0.08 seconds, 0.16 seconds or 0.32 seconds

Stability Detector – to choose the desired stability for the balance i.e.

Low, Medium or High

3.7. Mode Key: Allows the user to call up functions which are activated

once this key is released, such as result, time and date printouts as well

as functions that affect the weighing mode such as switching from

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Unit1 to Unit2 or vice versa or else to change between percentage and

counting mode.

3.8. On/Off Key: To switch the balance on or off.

3.9. T-Key: Used to tare the balance when this is in weighing mode. May

also be used to enter configuration menu or main menu, to change from

one parameter to the next in the individual sub-menus, to exit a menu

and also to call up the calibration programme.

3.10. Tare: Allows the balance to display the weight of the sample only and

not the combined weight of the sample and its container.

3.11. Unit1: The basic unit in which values are to be displayed in. This can

be set as the gramme [g], grain [GN], penny weight [dwt], troy ounce

[ozt], ounce [oz], pound [lb], carat [ct], metric carat [C.M.], Hong Kong

tael [tlH], Malaysian tael [tlM] or Taiwan tael [tlT].

3.12. Unit2: The secondary unit that can be programmed in the main menu.

This can bet set as one of the units chosen for Unit1 with the addition

of the count [PCS] or percent [%].

3.13. Weighing pan: The area on top of which the material to be weighed is

placed.

4. Responsibility

4.1. The members of the Department of Pharmacy (staff and students) are

responsible for following this SOP.

4.2. The designated Laboratory Officer or Laboratory Assistant is

responsible for ensuring that this SOP is followed.

5. Procedure

5.1. Installation

5.1.1. Place the balance on a stable surface, away from any vibrations.

5.1.2. Turn the adjustable feet/levelling screws at the bottom of the

balance clockwise or anticlockwise until the air bubble in the

spirit level is in the centre of the marked circle.

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5.1.3. Insert power supply connector in the plug on the rear of the

balance and plug the power supply into the mains supply.

5.1.4. Press the On/Off Key to activate the balance.

5.1.5. Wait until a stable 0,00 is displayed before use.

5.2. Configuration

5.2.1. Press and hold the T key whilst balance is still switched off.

5.2.2. Press the On/Off key while still pressing the T key.

5.2.3. Keep the T key pressed until the desired configuration

parameter is displayed (see SOP/PD/304_01/A1).

5.2.4. Release the T key to access the desired configuration

parameter.

5.2.5. Press the T key briefly but continuously until the desired

function in the configuration parameter is displayed.

5.2.6. Press and hold the T key again to return to main menu. If this is

not pressed for some time, the configuration menu will be

abandoned automatically, and the standard configuration

stored.

5.3. Using the Main Menu

5.3.1. Press and hold the T key until the desired option is displayed.

5.3.2. Release the T key to enter the desired sub-menu.

5.3.3. Press the T key briefly but continuously until the desired

parameter in the sub-menu is displayed.

5.3.4. Press and hold the T key to return to the main menu. If this is

not pressed for some time, the main menu is automatically

abandoned and the balance enters weighing mode once again.

5.4. Weighing Mode

5.4.1. Ensure that the desired weighing unit is displayed. If this is not

so, press the MODE key until it is displayed if it had been

previously set as the basic unit i.e. Unit1 or as the secondary

unit i.e. Unit2.

5.4.2. Place sample onto the weighing pan and read off value.

5.4.3. If using the tare function, place empty weighing container on

the weighing pan, press the T key and then place the sample in

the weighing container and read of the tared value from the

display.

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5.4.4. Use the tare function repeatedly if necessary.

5.5. Using the Mode Key

5.5.1. Counting Mode

5.5.1.1. Ensure that ‘PCS’ was previously set as Unit2 from

the main menu.

5.5.1.2. Place the number of pieces that are required as

reference weight on the weighing pan.

5.5.1.3. Press and hold the MODE key until [Unit2 PCS] is

displayed.

5.5.1.4. Release the MODE key to select the reference weight

as the selected number of pieces and also to switch

automatically to Unit2 i.e counting mode.

5.5.1.5. Remove the number of pieces used to set the

reference weight.

5.5.1.6. Place the weight that needs to be counted and read

the number of pieces from the display.

5.5.2. Percentage Mode

5.5.2.1. Ensure that ‘%’ was previously set as Unit2 from the

main menu.

5.5.2.2. Place the reference weight on the weighing pan.

5.5.2.3. Press and hold the MODE key until [reF 100%] is

displayed.

5.5.2.4. Release the MODE key to set the reference weight as

the selected percentage and also to switch

automatically to Unit2 i.e percentage mode.

5.5.2.5. Remove the reference weight used to programme the

percentage function.

5.5.2.6. Place the desired sample and read the percentage of

the reference weight from the display.

5.6. Calibration

5.6.1. Allow a ‘warm up’ time of about 10 minutes after switching the

balance on.

5.6.2. Press and hold the T key until [CAL] is displayed

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5.6.3. Ensure that there is nothing present on the weighing pan. If pan

is not empty, and/or the balance is active, the digital display

[--0000g] will continue to flash.

5.6.4. Allow [0000g] to be displayed to indicate that zero point

measurement has been carried out.

5.6.5. Wait until balance display flashes [--1000g] and then place the

recommended calibration weight (1000g) on the centre of the

pan.

5.6.6. Wait until display shows [1000g] to indicate that calibration is

finished and balance returns to weighing mode

5.7. Maintenance

5.7.1. Disconnect balance from its power supply before attempting to

clean and leave it in its normal operating position.

5.7.2. Use a clean fine brush to remove any surrounding powder.

5.7.3. Use a moistened cloth with a mild cleaning agent to clean and

remove any spilt material.

5.7.4. Ensure that the air bubble in the spirit level on the front end of

the scale is in the centre of the marked circle.

5.8. Troubleshooting

Fault Possible Cause

Display does not light up

- Balance not switched on correctly

- Balance not connected to mains

- Power failure

- Faulty microfuse

‘OL’ is displayed - Weighing limit has been exceeded

‘UL’ is displayed

- Weighing pan and/or pan support has

not been assembled

Weighing display changes continuously

- Draught/ air currents present

- Vibrations on table/floor

- Weighing pan touching foreign body

Result seemingly incorrect

- Balance not tared

- Balance not levelled

- Outdated calibration

- Strong temperature fluctuations

Display flashes continuously during

calibration

- Location of balance is undesirable

- Calibration weight is too imprecise or

does not correspond to the

recommended one

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5.9. Flow Charts

5.9.1. Installation

Place on stable surface, away from any vibrations

Turn adjustable feet until air bubble in

spirit level is in the centre of the

marked circle

Insert power supply connector in the

plug on rear of balance and plug power

supply into mains supply

End

Start

Press On/Off Key to activate balance

Wait until a stable 0,00 is displayed

before use

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5.9.2. Configuration

Press and hold T key whilst

balance is still switched off

Press On/Off key while still

pressing the T key

Press T key briefly but

continuously until desired

function is displayed

Release T key to access desired

configuration parameter

Keep T key pressed until desired

menu is reached

Desired

configuration parameter

displayed

Save changes

made

Press and hold the T key to save

and return to main menu

End

Yes

Yes

No

No

Start

Do not press any keys and allow balance to automatically return to

weighing mode

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5.9.3. Using the Main Menu

Press and hold T key

Desired option displayed

Keep T key pressed until desired

parameter is reached

Release T key to enter its sub-

menu

Press T key briefly but

continuously until desired

parameter is reached

Parameter saved and returns to

main menu

End

Yes

Yes

No

No

Start

Save changes made

Do not press any keys and allow balance to automatically return to

weighing mode

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5.9.4. Weighing Mode

*x represents desired weighing unit

Start

Desired weighing

unit display

Press and hold MODE key

Desired weighing

unit previously set

as Unit1 orUnit2

Press On/Off key to switch off

balance

Release MODE key when [Unit1

x*] or [Unit2 x*] is being displayed

Release T key when [Unit1] is displayed

Press and hold T key and

simultaneously press the On/Off

key again

Briefly but continuously press T

key until [Unit1 x*] is displayed

Press and hold T key to save and

return to main menu

Allow balance to enter weighing mode

Press and hold MODE key until [Unit1 x*] is displayed

Press T key

Place sample and

container onto

weighing pan

Read off value from

the display

1

1

Using tare

function

Place empty weighing container on balance

Place sample in weighing

container

Keep using tare function

repeatedly if necessary

1

End

Yes

Yes

Yes

No

No

No

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5.1.1. Using the Mode Key

Change balance

to counting mode

‘PCS’ previously set as

Unit2 from main

menu


until [Unit2 PCS] is displayed

Place number of pieces

required as reference on pan

Release MODE key to select the reference weight and to

switch automatically to Unit2

Remove number of pieces used to set reference weight

and place the weight that needs

to be counted

Read the number of pieces

from the display

Press and hold T key until

[Unit2] is displayed

Press T key briefly and

continuously until [Unit2 PCS]

is displayed

Press and hold T key to save


Change balance

to percentage mode

‘%’ previously set as Unit2

from main menu

Place reference weight on

weighing pan


until [reF 100%] is displayed

Release MODE key to set reference weight as the

selected percentage and to

switch automatically to Unit2

Remove reference weight and

place desired sample

Read the percentage of the reference weight from the

display

End

1

1


[Unit2] is displayed

Press T key briefly and continuously until [Unit2 %] is

displayed

Press and hold T key to save


Yes

No

No

No

No

Yes

Yes

Yes

Start

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5.1.2. Calibration

Start


[CAL] is displayed

Digital display

[--0000g] continues to

flash

Remove anything that may be

present on weighing pan

No

Yes

Allow [0000g] to be displayed

Wait until display flashes

[--1000g]

Place standard 1000g on centre

of weighing pan

Balance returns to weighing

mode

Wait until display shows a

stable [1000g]

End

Allow a ‘warm up’ time of

about 10 minutes after balance

is switched on

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5.1.3. Maintenance

Balance needs

cleaning

Disconnect balance from power supply

Any

surrounding

powder

Remove using a fine brush

Any spilt

material

Remove using a moistened cloth with a mild cleaning

agent

Air bubble in spirit level is in

centre of marked circle

End

Manipulate adjustable feet

until this is accomplished

No

Yes

Yes

Yes

Yes

No

No

No

Start

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6. Precautions

6.1. Do not install near extremes of heat and cold.

6.2. Protect balance from dust and air draughts.

6.3. Keep weighing pan clean and dry to prevent inaccuracies.

6.4. Do not move balance during weighing.

6.5. Ensure that the maximum tolerate weight of 180g is not exceeded

during weighing procedures and also when using the tare function.

6.6. Do not leave any items on the balance when this is not in use.

6.7. Only use balance if the spirit level is correct.

6.8. Adjust the air bubble in the spirit level each time the balance is to be

moved to another location.

6.9. If an error message is displayed when balance is switched on, switch

balance off and on again. If error message re-appears, contact supplier

for further information .

6.10. Avoid static charge buildup of the material to be weighed and of the

weighing container.

6.11. When transferring balance to a significantly warmer environment,

allow it to acclimatise for approximately 2 hours at room temperature

after it has been disconnected from the mains.

7. References

N/A

8. Appendices

SOP/PD/305_01/A1 – Configuration Parameters Table

9. Revision History

Version Number Amendments/ Reasons for change

01 Initial Release

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SOP/PD/305_01/A1 – Configuration Parameters Table

Configuration

Parameter

Display Symbol Function

Basic unit of balance Unit1

To choose the weighing unit to be set as

Unit1

Calibration CAL

To choose whether to carry out calibration

[CAL YES] or to disable this function [CAL

NO]

Baudrate bdr To choose the desired baudrate from [300

bdr], [600 bdr], [1200 bdr], [2400 bdr],

[4800 bdr] or [9600 bdr]

Parity PAr To choose between having no parity [PAr

no], an odd parity [PAr odd] or an even

parity [PAr E]

Printing Print To choose between no printing [Print no],

single printout of each value [Print UST],

single printout of each stable value [Print

ST],auto printout after changing load [Print

Lch] or continuous printout [Print PEr]

Combined print

function

Prt-ALL To combine a printout with weighing result,

date and time etc [Prt-ALL YES] or else to

disable this function [Prt-ALL no]

Delay Printout Prt-dEL To delay printout by 0.5, 1 or 2 seconds or

else to disable this delay function [Prt-dEL

no]

Last Digit LASt d To choose whether the last digit is to be

always visible [LASt d on] or only visible

when stable [LASt d off]

Automatic zero

adjustment

A-ZEro To choose whether this is to be switched on

[A-ZEro on] or off [A-ZEro off]

Menu Inhibit LAtch To choose whether to inhibit changes from

being made to the configurations parameters

menu [LAtch on] or else to disable this option

[LAtch oFF]

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Status Printout StAtUS Prt To perform a printout of all the information

available about the balance including the

parameters that are set in the main and

configuration menus

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