46 Rockwell Automation Publication 440R-UM013E-EN-P - March 2017
Chapter 7 EMD Safety Relay Timing Functions
Case 2
4. The logic link signal at terminal L12 turns on, and the safety outputs
turn on within the specified reaction time.
5. The logic link signal turns off and the off-delay timer starts.
6. During off-delay time, the logic link signal turns off. A recoverable fault
occurs. The PWR/Fault indicator is green and flashing red four times.
7. The off-delay time has elapsed, and the safety outputs turn off.
8. The logic link signal turns off.
9. Shortly after the logic link turns off, the fault is automatically cleared.
The PWR/Fault indicator is solid green.
Case 3
10. The logic link signal at terminal L12 turns on, and the safety outputs
turn on within the specified reaction time.
11. The logic link signal turns off and the off-delay timer starts.
12. During off-delay time, the logic link signal turns off. A recoverable fault
occurs. The PWR/Fault indicator is green and flashing red four times.
13. The logic link turns back off. The fault continues to exist.
14. The off-delay time has elapsed; the safety outputs turn off; and the fault
is automatically cleared.
Off Delay, Retriggerable
To use the retriggerable off-delay function, input terminal B1 must be
connected to terminal B2 before the configuration process. The off-delay timer
starts when the logic link signal at terminal L12 turns off. During the timing
cycle, the off-delay timer is automatically reset to zero when the logic link turns
back on. Figure 33
shows two cases of the timing sequences that can occur with
this configuration.
Figure 33 - Off-delay, Retriggerable Timing Diagram
Case 1
1. The logic link signal at terminal L12 turns on, and the safety outputs
turn on immediately (that is, within the specified reaction time).
2. The logic link signal turns off, and the off-delay timer starts.
3. The off-delay time has elapsed, and the safety outputs turn off.
Case 1 Case 2
L12
Safety
Outputs
t t t
12 3 4 5 6 7 8
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