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2.7.4 COMMUNICATION SIGNAL CONNECTIONS
The communications terminal assignments change based on the type of option installed. If
present in a control module, the type of communications interface will be identified by a label
located next to the module’s rating label.
Communications wiring should use twisted conductor, shielded cable. Shields on communica-
tions wiring should be grounded at one end only, using the terminals provided.
The following tables define the appropriate signal connections for the various types of interfaces:
2.7.5 POWER CONNECTIONS
All of the power terminals are numbered for easy identification. Do not attempt to use wire sizes
that exceed the marked terminal ratings and avoid terminating two wires on the same terminal
whenever possible.
Always be sure that all terminals are adequately tightened according to the terminal manufac-
turer’s specification. See Appendix A on page 61 for allowable wire sizes, recommended insula-
tion strip lengths, and tightening torque. A loose terminal can cause arcing and damage to the
terminal or incorrect operation of the controller.
Note: Make sure that power terminals are re-tightened several days after installation. Stranded
wire will tend to compress when initially installed; therefore, these terminals should be checked
for tightness several times after the system is installed to ensure that a good connection is main-
Miscellaneous Signals Terminal No.
External input (+) 20
External input (-) 21
External output (+) 4
External output(-) 5
RS-485 (2-Wire) Connections
Communication Signal Terminal No.
Receive/transmit data (+) 6
Receive/transmit data (-) 22
Shield 8
Shield 24
RS-232 Connections
Communication Signal Terminal No.
Receive data 6
Data carrier detect 7
Clear to send 8
Transmit data 22
Request to send 23
Common 24
Modem Interface Connections (Note that these particular signals are not polarity sensitive)
Communication Signal Terminal No.
Modem 6
Modem 22
Shield 8
Shield 24
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