Maximum Voltage1 Connect only voltages that are within the following limits.
Vsup-to-COM.....................................36 VDC, Measurement Category 1
Measurement Category I is for measurements performed on circuits not directly connected to the electrical distribution system referred to as MAINS voltage. MAINS is a hazardous live electrical supply system that powers equipment. This category is for measurements of voltages from specially protected secondary circuits. Such voltage measurements include signal levels, special equipment, limited-energy parts of equipment, circuits powered by regulated low-voltage sources, and electronics.
Caution Do not connect the NI 9476 to signals or use for measurements within Measurement Categories II, III, or IV.
The maximum voltage that can be applied or output between Vsup creating a safety hazard.
and COM without
NI 9476 Operating Instructions and Specifications