NI 9234 Operating Instructions and Specifications 28 ni.com
Safety

Safety Voltages

Connect only voltages that are within the following limits.
Channel-to-earth ground...................±30 V max,
Measurement Category I
Isolation
Channel-to-channel.................... None
Channel-to-earth ground............ None
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 9234 to signals or use for
measurements within Measurement CategoriesII, III,
orIV.