80 HC900 Process & Safety Controller User and Installation Manual Revision 6
21 April 2017
Remote Termination Panel (RTP)
The optional Remote Termination Panel (RTP) provides an easy way to connect the HC900 controller to
the field wiring. The RTP integrates some of the typical externally connected components, reducing wiring
and setup time. It also minimizes the need for multiple wires under a single screw connection by
expanding the connectivity of the shared terminals of the I/O modules.
See Appendix - Installation of Remote Termination Panels (RTPs) page 217 for details.
Terminal Block-to-Field (Signal) Wiring
Although both of the two available terminal block styles can be used on all I/O module types, wiring
methods vary with the module type and with the type of field devices connected to the terminal block. The
descriptions that follow provide details.
Wiring can be routed through the terminal block at the top, at the bottom, or both. Wiring should be fixed
in place using wire ties at the slotted tabs that are molded in at top and bottom of each terminal block.
Wiring Rules and Recommendations
In general, stranded copper wire should be used for non-thermocouple electrical connections. Twisted-pair
wiring with shielded cable is recommended and will improve noise immunity if wire routing is suspect.
Wire Gage
Observe all local codes when making power connections. Unless local electrical codes dictate otherwise,
the recommended minimum wire size for connections is given in Table 12.
Table 12 – Minimum Recommended Wire Sizes
Earth ground to common power supply.
DC current and voltage field wiring
DC current and voltage wiring in control room
Routing and Securing Wires
Typically, field wiring is routed to connections at a terminal panel near the controller and then from the
terminal panel to the terminal blocks on the I/O modules.
Whatever method of routing is used, wiring must be mechanically supported along its length, and must be
protected from physical damage and electromagnetic (noise) interference. (See Electrical Considerations
page 56.)
Also, all wires must be securely terminated, using appropriate wiring practices.
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