Справочник Пользователя для National Instruments NI 9474

This category refers to local-level electrical distribution, such as 
that provided by a standard wall outlet, for example, 115 V for U.S. 
or 230 V for Europe.

Do not connect the NI 9472/9474 with screw 

terminal to signals or use for measurements within 
Measurement Categories III or IV.

Connect only voltages that are within the following limits.

Channel-to-COM .............................. 30 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