Rockwell Automation Publication 440R-UM013E-EN-P - March 2017 47
EMD Safety Relay Timing Functions Chapter 7
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 on. The off-delay timer
is set back to zero, and the safety outputs remain on. No fault occurs.
7. The logic link signal turns off, and the off-delay timer starts.
8. The off-delay time has elapsed, and the safety outputs turn off.
On Delay
To use the on-delay function, terminal B1 must be an open connection. The
on-delay timer starts when the logic link signal at terminal L12 turns on. The
safety outputs turn on after the delay time expires and remain on until the logic
link signal turns off. If the logic link signal turns off during the timing cycle, the
safety outputs turn off immediately. Figure 34
shows two cases of the timing
sequences that can occur with this configuration.
Figure 34 - On-delay Timing Diagram
Case 1
1. The logic link signal at terminal L12 turns on, and the on-delay timer
starts.
2. The on-delay timer elapses, and the safety outputs turn on.
3. When the logic link signal turns off, the safety outputs turn off.
Case 2
4. The logic link signal at terminal L12 turns on, and the on-delay timer
starts.
5. The logic link signal turns off before the on-delay time elapses. The on-
delay timer is reset to zero. No fault occurs.
6. After a brief interruption (even as short as 100 ms), the logic link signal
turns back on. The on-delay timer starts from zero.
7. The on-delay timer elapses, and the safety outputs turn on.
8. When the logic link signal turns off, the safety outputs turn off.
Case 1 Case 2
L12
Safety
Outputs
t t
12 34567 8
t
To Next Page
Loading...
