SOP for Operation & Calibration of Top Loading Balance

To lay down the procedure for operation and calibration of the Top Loading Balance for better and error-free use.

This procedure is applicable for Balance (MAKE: Ohaus Corporation, MODEL: V31XH202)

Execution: Chemist and above – QC department.
Checking: Asst. Manager and above – QC department


Operation Procedure
  • Make sure that the balance is kept clean.
  • Ensure that the calibration status is valid.
  • Ensure that the spirit level is in the center of the circle.
  • Connect the power cable to the mains and switch ‘ON’.
  • Press ON/OFF key, all the display will glow.
  • Press “TARE KEY”, 0.00 mark appears on display.
  • Once the stability is attained, the balance is ready for weighing.
  • Place the material to be weighed on the pan & note down the reading.
  • Clean the balance immediately after weighing

Preliminary Checks for Balance Calibration
  • Spirit Level Check (Balance Levelling):
  1. Adjust the air bubble to the centre of the inner circle of the indicator if it is not in the centre.
  2. Acceptance Criteria: Air bubble must be in centre of inner circle.
  • Pan Cleaning and Adjustment:
  1. Before placing the std. weight/butter paper/glassware, clean the pan properly
  2. Also ensure that the pan is adjusted correctly (if not adjusted before).
  3. Acceptance Criteria: Pan must be cleaned and centrally placed.
  • Zero Error Check:
  1. Press the ON/OFF key and wait till LCD shows zero.
  2. Acceptance Criteria: LCD should display zero on the LCD screen.
  • Handling of Weight Box:
  1. Ensure that the weights used are calibrated and certified on a regular basis.
  2. Always use forceps/tweezers to place the weight on the balance pan.
  3. Do not drop the weight with force on the pan of the balance, to avoid any variation in the results
  4. Weights used for calibration should always be cleaned with tissue paper before & after each use
  5. Acceptance Criteria: Weights should not have any denting or damage sign and should be cleaned before and after each use.

Calibration Procedure

External Calibration
  • Place 1g weight on the weighing pan.
  • Note down the observed weight
  • Repeat the above steps using 100g and record the reading in Annexure-1
  • Acceptance Criteria: Each weight should not differ by more than 0.1% of the actual weight.

SOP : Standard Operating Procedure
No. : Number
Dept. : Department
QC : Quality Control
Asst. : Assistant
g : Gram
LCD : Liquid Crystal Display

Annexure No. - 1 -- Preliminary Checks & Calibration Record of the Balance


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