Section 2.7 Wiring Your Module - Spectrum Controls SLC 500 User Manual

2-6 Chapter 2: Installation and Wiring
Section 2.9
Wiring Your
Module
WARNING
User's Manual Pub. 0300128-04 Rev. A
its backplane connector. Never force your module into the slot.
Cover all unused slots with the Card Slot Filler, Allen-Bradley part
number 1746-N2.
To remove your module, press the retaining clips at the top and bottom
of your module and slide it out.
To wire the terminal block, you need:
• A small, flat-blade screwdriver.
• Belden 8761 (shielded, twisted pair) cable or equivalent.
Remove power before removing or inserting this module. When you
remove, or insert, a module with power applied, an electrical arc may
occur. An electrical arc can cause personal injury or property damage by:
• Sending an erroneous signal to your system's field devices,
causing unintended machine motion.
• Causing an explosion in a hazardous environment.
• Electric arcing causes excessive wear to contacts on both the
module and its mating connector and may lead to premature
failure.
Before wiring the terminal block, take some time to plan your system:
Ensure that the SLC 500 system is installed in a NEMA-rated enclosure
•
and that the SLC 500 system is properly grounded.
Ensure that the load resistance for a current output channel is less than
•
500 Ω.
• Ensure that the load resistance for a voltage output channel is greater
than 1 kΩ.
• Route the 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. Generally, allow at least 6 in. (about 15.2 cm) of
separation for every 120 V of power.
Routing the field wiring in a grounded conduit can reduce electrical
•
noise further.
• If the field wiring must cross AC or power cables, ensure that they cross
at right angles.
To wire your module, follow these steps:
1. Determine the length of cable you need to connect a channel to its field
device. Remember to include additional cable to route the drain wire and
foil shield to their ground points.
2. At each end of the cable, strip some casing to expose the individual
wires.
3. Trim the exposed signal wires to 2 in. lengths. Strip about 3/16 in. (about