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When multiple guard locking devices are installed on a GuardLink system, the
DG safety relay inserts a short delay between commands to each successive
device to minimize the momentary inrush current to the solenoids. The device
closest to the DG safety relay receives the command first. The device furthest
away from the DG safety relay receives the command last.
The delay between commands is between 135...300 ms. When a few guard
locking devices are used, the delay is 135 ms. As more guard locking devices are
included in the circuit, the delay increases. When 32 guard locking devices are
used, the delay can be up to 300 ms between each device.
Figure 4
shows an example timing diagram. The delay switch is set to
position 5 (1 second delay). The first guard unlocking command starts at
1000 ms. The second unlock signal occurs at 1135 ms. The third unlock signal
occurs at 1270 ms. If 32 guard locking devices are installed, the last one receives
the unlock command at 10,600 ms.
Figure 4 - Unlock Command Timing Diagram
32
5
4
3
2
1
OUT (13/14, 23/24)
OUT X (X2)
Unlock Request
0
Guard Locking Application Example
Figure 5 on page 20
shows a typical guard locking application example. The
DG safety relay has four taps on the GuardLink circuit:
• First tap — SensaGuard™ integrated-latch interlock switch
• Second tap — 440G-LZ guard locking interlock switch
• Third tap — TLS –ZR guard locking switch
• Fourth tap — SensaGuard flat-pack interlock switch
The TIME switch on the DG safety relay is set to position 9, which provides a
5 second delay to allow the motor to coast to a full stop.
Rockwell Automation Publication 440R-UM015C-EN-P - April 2018
1000
1135
1270
1405
1540
Time [ms]
Overview
Chapter 1
10,600
19
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