Shield Grounding - Spectrum Controls 1769 User Manual

• 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 ensure optimum accuracy, limit overall cable impedance by keeping
•
your cable as short as possible. Locate the I/O system as close to your
sensors or actuators as your application will permit.
• 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.
• Tighten terminal screws with care. Excessive tightening can strip a
screw.

Shield Grounding

• 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.
• Use Belden shielded, twisted-pair wire to ensure proper operation and
high immunity to electrical noise. Refer to the following table and the
RTD Wiring Considerations below.
Configuration
2-wire
3-wire
Less than 30.38 m (100 ft.)
3-wire
Greater than 30.48 m (100 ft.) or high
humidity conditions
• Under normal conditions, the drain wire and shield junction should be
connected to earth ground, via a panel or DIN rail mounting screw at the
1769sc-IR6I module end.
• If noise persists for a device, try grounding the opposite end of the cable.
(You can only ground one end at a time.)
Refer to Industrial Automation Wiring and Grounding Guidelines, Allen-
Bradley publication 1770-4.1, for additional information.
• Ground the shield drain wire at one end only. The preferred location is
as follows.
-
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.
Chapter 1: Module Overview
Recommended Cable
Belden™ 9501 or equivalent
Belden™ 9533 or equivalent
Belden™ 83503 or equivalent
User's Manual Pub. 0300241-02 Rev. A
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