SOP For calibration of hardness tester is described in this post which you can follow in the section of the General Industry SOP.

OBJECTIVE
To calibrate the equipment for reliable and accurate results.
SCOPE
This procedure is applicable to calibrate Hardness tester, installed in the quality control area.
RESPONSIBILITY
Quality Control analyst 
ACCOUNTABILITY
Manager Quality Control
PROCEDURE
Select “configuration” menu from the main menu.
Select “calibration” sub menu and press enter
Enter password “Calibration” and press enter.
Following four matters can be calibrated by this instrument.
  1. Balance
  2. Hardness tester
  3. Diameter
  4. Thickness
Calibration of Mettler Balance
  • Select the menu ‘Balance’ and press enter.
  • After a first beep tone, a weight value at 50.000 gm is indicated by blinking.
  • Put 50.000 gm weight onto the balance boat and close the cover.
  • After a second beep tone give the massage of remove 50.000 gm weight from the balance boat.
  • Confirm the calibration with ‘enter’ and check the accuracy of the balance with 3 different calibrator weight and enter as nominal value and receive actual value.
  • Calibration of Diameter
  • Select the menu item ‘Diameter’ from the sub menu ‘calibration’ and enter.
  • A gauge block size of 10 nm is entered as standard.
  • To check the accuracy of Diameter calibration with 3 different calibrated gauge block.
  • Enter the nominal value and receive actual value.
Calibration of Thickness
  • Select the menu item ‘Thickness’ from the sub menu ‘calibration’ and enter.
  • Clean the measuring plate and the tablet track with brush and press enter.
  • Insert 5mm calibrated block and press enter.
  • To check the accuracy of thickness calibration with 3 different calibrated gauge block.
  • Enter the nominal value and receive actual value.
  • After exit the calibration menu, calibration protocol printout by ‘Print out OK’ message.
Frequency: Once in 3 month