Rockwell Automation 1771-IS 5V DC INPUT MOD - Manual (Page 15)

Module Preparation, Wiring, and
Installation
Chapter 2
2-8
Important: The selection of the four field wiring arm terminals, either 2,
3, 4, 5 or 6, 7, 8, 9 is critical for correct transfer of switch status data.
The point-to-point wiring schematics show all electrical connections for
the first of several parallel switch assemblies. The wiring of additional
assemblies is shown conceptually (in the upper portion of each
schematic). Switch lines 8, 4, 2, 1 are wired to each additional switch
assembly using decoupling diodes identically to the first switch assembly.
Enable line(s) for each additional switch assembly are specified in the
conceptual part of the drawing.
The enable lines, A through I, are wired to field wiring arm terminals 18
through 10, respectively. Note that enable line A is connected to field
wiring arm terminal 18, etc. It may be desirable to terminate thumbwheel
switch lines 8, 4, 2, 1 at a terminal block on the switch panel. A single set
of switch lines 8, 4, 2, 1 and enable lines should be contained in a shielded
cable connecting the switch panel to the field wiring arm to minimize
connections at the field wiring arm terminals.
Observe the following practices when wiring thumbwheel switches:
Bundle thumbwheel switch wiring separately from other wiring.
Shielded cable is recommended.
Ground the shielded cable only at the I/O rack. The shield must remain
ungrounded at the other end.
Discrete Switch Bank Wiring
Up to 72 discrete contact switches can be wired to the module as shown in
Figure 2.6. These switches can be momentary contact or maintained
contact switches. Refer to section titled “Thumbwheel Switch Wiring”
for wiring guidelines and practices.