Rockwell Automation Publication 440R-UM013G-EN-P - December 2022 29
Chapter 3 Power, Ground, and Wire
Monitor with Expansion Relays
Monitoring of the expansion relays is recommended. This feature is especially useful when the
expansion relay is turning on loads (for example, solenoid-operated valves) that do not have
monitoring contacts. The auxiliary output of the expansion relay must be the 24V DC source of
the reset and monitoring input. Figure 25
shows an example of the connections for a
monitored reset with additional contactor monitoring. You can also use this type of connection
for automatic reset applications.
Figure 25 - Monitor Expansion Relay
Retriggerable Input The B1 and B2 inputs determine the type of timing function.
•B1 and B2 open: Off-delay non-retriggerable or on-delay
• B1 connected to B2: Off-delay retriggerable
• B1 connected to 24V DC: Jog
The EMD safety relay has a retriggerable input. Retriggerable operation only works in off-delay
applications. Retriggerable operation is accomplished by connecting a jumper from terminal
B1 to B2. Table 5
describes the off-delay operation.
Jog Input When the EMD safety relay is configured for the Jog functions, terminal B1 must connect to
+24V DC.
+24V DC
24V DC Com
S34
A1
A2
X32
A1
A2
Contactor
Monitoring
Momentary Push
Button (N.O.)
CI, DI, DIS, or SI EM or EMD
Table 5 - Retriggerable Operation
Configuration Jumper Action
Retriggerable B1-B2
If the safety input is triggered and cleared within the duration of the time delay,
then the timing request is ignored and the safety output contacts remain closed.
The B1 status indicator is on.
Non-retriggerable None
The full-time delay lapses and the safety output contacts open before the safety
relay can reset.
The B1 status indicator is off.
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