Spectrum Controls 1769sc-IT6I User Manual
Page 29
Chapter 3: Installation and Wiring
3-9
User’s Manual Pub. 0300244-01 Rev. A
•
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.
•
Keep cable shield connections to 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
•
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.
(You can only ground one end at a time.)
3.7.2
Terminal Door Label
A removable, write-on label is provided with the module. Remove the label from the
door, mark your unique identification of each terminal with permanent ink, and slide the
label back into the door. Your markings (ID tag) will be visible when the module door is
closed.
3.7.3
Removing and Replacing the Terminal Block
When wiring the module, you do not have to remove the terminal block. If you remove
the terminal block, use the write-on label located on the side of the terminal block to
identify the module location and type.
To remove the terminal block, loosen the upper and lower retaining screws. The terminal
block will back away from the module as you remove the screws. Be careful not to
damage the CJC sensors. When replacing the terminal block, torque the retaining screws
to 0.46 Nm (4.1 in-lbs).