SOP FOR Operation and Calibration of Electronic Weighing Balance

SOP FOR Operation and Calibration of Electronic Weighing Balance

1.0       OBJECTIVE

To lay down a standard procedure for operation and calibration of electronic weighing balance.

2.0       SCOPE

This Standard Operating Procedure is applicable for electronic weighing balance of quality control department installed in microbiological section.

I.D. No. SC/QCM/INST/028

Make: RADWAG wagl Elektronicze

Model: XA 82/220/2X


               Microbiologist shall be responsible to follow the procedure mention in this SOP.


Department Head & QA Head shall be accountable for compliance of this SOP.


Format for the Daily calibration record of electronic weighing balance                    – Attachment-I

Format for the Daily accuracy test record of electronic weighing balance                – Attachment-II

6.0       PROCEDURE

6.1           Precautions

6.1.1        Do not weigh on the pan directly. Always use butter paper.

6.1.2        Do not place heavy glassware on the pan. It may damage the instrument.

6.1.3        Do not place heavy glassware on the pan. It may damage the instrument

6.1.4        Close the glass doors on the sides and top before recording the weights.

6.1.5        Do not spill any material during weighing on the balance.

6.1.6        After completion of weighing keep the inside area clean.

6.1.7        Use moistened soft cloth or tissue paper to clean the balance.

6.1.8        Switch ON the balance at least 30 minutes before operation of weighing.

6.2           Installation

6.2.1        Ensure that the balance is leveled or aligned.

6.2.2        The two leveling screws are adjusted so that the bubble is in the middle of the circle.

6.2.3        Switch ON the main power supply of balance.

6.3           Operation

6.3.1        Make sure that the balance is cleaned and free from dust.

6.3.2        Ensure that spirit level is in the center of the circle.

6.3.3        Ensure that the calibration status is valid.

6.3.4        Connect the Power cable to the mains and switch ON.

6.3.5        Automatically self checking starts.

6.3.6        Press ON/OFF key, all the display will glow.

6.3.7        Press “Tare key”, 0.00000 mark appears on the display.

6.3.8        The stability of the reading is obtained which is indicated by an arrow mark on the left side of the display.

6.3.9        Once the stability is attained, the balance is ready for weighing.

6.3.10      Place a container or a piece of butter paper on weighing pan, close the glass doors and press the tare key, the display changes to 0.00000.

6.3.11      Open the glass doors from the sides and place the material to be weighed on the weighing pan & note  down the reading after the arrow mark appears on                       the left side of the display.

6.3.12      After the completion of weighing press “ON/OFF” key. “STAND BY” light glows.

6.3.13      Clean the balance immediately after weighing.

6.4           Calibration

6.4.1        Daily calibration     Make sure that the balance is cleaned and dust free.     Ensure that spirit level is in the center of the circle.     Calibrate the balance daily with standard weights of 10mg, 20 mg, 50 mg, 100 mg, 200 mg, 500 mg,

5 gm, 10 gm, 20 gm, 50 gm, and 100 gm. Now place each weight from the weight box one after

another in ascending order starting from 10 mg to 100 gm and record the observations in the

respective daily calibration data sheet.

6.4.2        Daily verification by accuracy test     Before placing any weight on weighing pan, ensure that 0.00000 is displayed on the screen and the

display is not fluctuated.     In case a numerical value other than zero is displayed on the display screen, make it zero by pressing the tare key.     Place standard weight of 5 gm on the weighing pan.     Note the weight and calculate the difference between the weight in certificate and observed weight.     Repeat the above steps using 50 gm & 100 gm weights.

  •         Record the observation in relevant document.

6.5           Acceptance criteria : ± 0.10 % of absolute value of standard weight ( take absolute value from calibration certificate )

6.6           Frequency:

  •        Daily: Internal calibration (i.e. daily calibration) and verification by accuracy test.

7.0           REFERENCES

United states Pharmacopoeia 39.


SOP:  Standard operating procedure

Gm  :  gram

%    :  Percent

NMT : Not more than

QA  : Quality Assurance

QC  : Quality Control



Quality Assurance Department

Quality Control Department


Version Number Effective Date Reason for Revision



Title : Daily Accuracy test record of electronic balance


Version No. : 00 Page No. : Page 1 of 1


Effective Date :   Review Date :  
Standard weights Weight in certificate  


Acceptance criteria: ± 0.10 % of absolute value of standard weight

5 gm  
50 gm  
100 gm  




Weight Observed Done by Checked by Remarks
5 gm 50 gm 100 gm