National Instruments RS485 - Manual (Page 4)

NI 9871 Operating Instructions 4 ni.com
Caution For Zone 2 applications, install a protection
device between the RS485/RS422 signal cables and the
NI 9871 RJ-50 jacks (ports 1– 4). The device must
prevent the RS485/RS422 signal-to-signal or
signal-to-COM voltage from exceeding 23 V if there is a
transient overvoltage condition.
Caution For Zone 2 applications, install a protection
device between the external power supply and the
NI 9871 V
sup
and COM pins. The device must prevent the
V
sup
-to-COM voltage from exceeding 39 V if there is a
transient overvoltage condition.
Special Conditions for Hazardous Locations in Europe
This equipment has been evaluated as Ex nA IIC T4 equipment
under DEMKO Certificate No. 07 ATEX 0626664X. Each module
is marked
II 3G and is suitable for use in Zone 2 hazardous
locations. If you are using the NI 9871 in Gas Group IIC hazardous
locations or in ambient temperatures of –40
°C ≤ Ta ≤ 70 °C, you
must use the device in an NI chassis or controller that has been
evaluated as EEx nC IIC T4, Ex nA IIC T4, or Ex nL IIC T4
equipment.