National Instruments NI 9425 - Manual (Page 14)

NI 9425 Operating Instructions and Specifications 14 ni.com
Safety
Safety Voltages
Connect only voltages that are within the following limits.
Channel-to-COM .............................. 60 VDC max
Isolation
Channel-to-channel .................... None
Channel-to-earth ground
Continuous ........................... 60 VDC,
Measurement Category I
Withstand ............................. 1,000 V
rms
, verified by a 5 s
dielectric withstand test
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.