Справочник Пользователя для National Instruments RS422

© National Instruments Corp.

Connect only voltages that are within these limits.

RS485/RS422 Port-to-COM.............  –8 to +13 VDC max, 

Measurement Category I

V

SUP

-to-COM ...................................  ±28 V max,

Measurement Category I

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.

Do not connect to signals or use for 

measurements within Measurement Categories II, III, 
or IV.

1  

The maximum voltage that can be applied or output without creating a safety hazard.