Technical data

66 34980A Service Guide
3 Calibration Procedures
Plug-in Modules
Plug-in Module Test Considerations
For optimum performance, all test procedures should comply with the
following recommendations:
• Assure that the calibration ambient temperature is stable and 
between 18 °C and 28 °C. Ideally the calibration should be 
performed at 23 °C ± 1 °C.
• Assure ambient relative humidity is less than 80%.
• Install the plug- in module and allow a 1 hour warm- up period before
verification or adjustment.
• Use shielded twisted pair PTFE insulated cables to reduce settling and
noise errors. Keep the input cables as short as possible.
• Remove all user wiring and connections from the plug- in modules
before verification or adjustment.
• Use 4- wire Ohms measurement techniques for checking relay contact
resistance. Check directly at the terminals where possible.