Rockwell Automation 1771-PM , D17716.5.18 U MNL 1771-PM CLUTCH/BRAKE MOD - Manual (Page 58)

Field Wiring Arm Connections
Chapter 6
6Ć6
When PM modules command triacs ON or OFF, they check that feedback
signals (triac, valve stem, air pressure, and motion detector) have turned
ON or OFF in the order shown and within the times shown.
If and when a PM module detects that a triac or feedback signal has not
turned ON or OFF within the times shown, it trips seal relay output to
remove power from the wiring arms of 1771-OD output modules.
Be sure that you configure your clutch/brake controller accordingly by
setting your backplane switches (chapter 3) and programming your
configuration bits (chapter 4).
Connect either one or both motion detector switches and either one or
both pressure switches if so configured.
If your main valves have external fault detection switches and you
configured for valve stem feedback, all other clutch/brake solenoid valves
must have external valve stem feedback. If auxiliary valve solenoids have
internal fault detection (do not have valve stem switches), jumper terminal
7 to terminal 0, Module group 2, slot 0 (Figure 6.2 or 6.6) in chassis A
and B.
There are two general types of solenoid valves: those with external fault
detection, and those with internal fault detection.
Solenoid valves with external fault detection have switches on the valve
stems which you use to feed back the status of valve stems to your
clutch/brake controller. The firmware in your clutch/brake module
performs the fault detection.
A valve with external fault detection, Figures 6.2 or 6.6, provides an
external signal of its valve position. When the valve is energized, the
external signal is “on”. Interfacing this type of valve to the clutch/brake
system requires:
enabling valve stem feedback with backplane switches (Figure 3.3)
enabling valve stem feedback in PC configuration rungs (Figure 4.3)
If you configure for valve stem feedback, all valves must have valve stem
feedback or simulate it (have their respective terminals jumpered to the
input terminals of the main valve stem switches for simulated inputs).
Internal/External Fault Detection