INFICON RQCM - Quartz Crystal Microbalance Research System - Manual (Page 89)

RQCM – RESEARCH QUARTZ CRYSTAL MICROBALANCE
DATA ACQUISITION CARD (OPTIONAL) 8-3
8.3 GROUNDING CONSIDERATION
Proper grounding and shield termination is mandatory for accurate measurements.
8.3.1 VOLTAGE MEASUREMENT GROUNDING
If the voltage to be measured is returned to earth ground (within the common mode voltage
range) at its source, neither the Input nor the Common lead should be grounded at the voltage
measurement point, since the RQCM will return to earth ground through its power cord. The
shield for the input leads must only be terminated at the Data Acquisition Card connector.
If the voltage to be measured is isolated from earth ground, the shield or its drain wire should be
connected to the common side of the voltage to be measured at the voltage source as well as at
the shield terminal on the RQCM Data Acquisition Card.
8.3.2 TEMPERATURE MEASUREMENT GROUNDING
All three temperature-sensors must be of the isolated or ungrounded type. Sensor lead wire
shields should be terminated at the RQCM Data Acquisition Card connector only. The measured
device should be connected to earth ground. Exposed junction probes should not be used to
measure the temperature in a conductive media like water.