Spectrum Controls 1762sc-IF8U - Manual (Page 18)

2-8 MicroLogix™ 1200 IO Universal Input Module
User's Manual Pub. 0300243‐02 Rev. B
!
Attention
UTILISER DES FILS D’ALIMENTATION QUI CONVIENNENT A
UNE TEMPERATURE DE 20°C AU-DESSUS DE LA
TEMPERATURE AMBIANTE
 This product is intended to be mounted to a well-grounded mounting surface
such as a metal panel. Additional grounding connections from the module’s
mounting tabs or DIN rail (if used) are not required unless the mounting surface
cannot be grounded.
 Under normal conditions, the drain wire (shield) should be connected to the
metal mounting panel (earth ground). Keep shield connection to earth ground as
short as possible.
 Ground the shield drain wire at one end only. The typical location is as follows:
o
For grounded thermocouples or millivolt sensors, this is at the sensor
end.
o
For insulated/ungrounded thermocouples, this is at the module end.
Contact your sensor manufacturer for additional details.
 If it is necessary to connect the shield drain wire at the module end, connect it to
earth ground using a panel or DIN rail mounting screw.
 Refer to Industrial Automation Wiring and Grounding Guidelines, Allen-
Bradley publication 1770-4.1, for additional information.
Noise Prevention
 Route field wiring away from any other wiring and as far as possible from
sources of electrical noise, such as motors, transformers, contactors, and ac
devices. As a general rule, allow at least 15.2 cm (6 in.) of separation for every
120V of power.
 Routing field wiring in a grounded conduit can reduce electrical noise.
 If field wiring must cross ac or power cables, ensure that they cross at right
angles.
 To limit the pickup of electrical noise, keep thermocouple and millivolt signal
wires as far as possible from power and load lines.
 If noise persists for a device, try grounding the opposite end of the cable shield
or ground both ends of the shield.
2.6.1 Wiring Diagram
Refer to the following wiring diagrams for field wiring connections.