User's Manual

20 Rockwell Automation Publication 440G-UM004C-EN-P - August 2020
Chapter 4 Wiring and System Integration
OSSD Mode Safety Signals
In OSSD mode, safety outputs Safety A and Safety B are OFF (0V) when the
switch is in safe state (that is, the switch is unlocked). When the switch is in
operational state (that is, closed and locked), safety outputs Safety A and Safety
B are ON (24V) and contain test pulses. The test pulses are used to detect short
circuits to 24V, to 0V and cross faults (from Safety A to Safety B). This
description of the test pulses is provided for informational purposes; you
cannot modify them.
Figure 7 - Output Test Pulses
GuardLink Mode Safety
Signals
When the 440G-MZ safety switch is connected in a GuardLink system, the
safety signals are Safety In and Safety Out. These signals are dynamic signals
in operational state and two-way communication signals in the safe state.
GuardLink System
Integration
Figure 8 on page 21 shows the basic components of a GuardLink system with a
DG safety relay master. The 440G-MZ safety switch, with embedded
GuardLink technology, connects to the link with a passive tap (as shown in
Figure 8 on page 21
) or a passive power tap (catalog number 440S-PF5D4).
IMPORTANT To prohibit nuisance tripping, mask the OSSD input channels of the safety
system with an On to Off delay of at least 1 ms.
5V/Div
Safety OSSD A
Safety OSSD B
2ms/Div
20ms/Div
OSSD test pulses into a 10K resistive load.
26 ms
580 μs
189 ms
5V/Div
Safety OSSD A
Safety OSSD B
ATTENTION: For information on a known anomaly, see Knowledgebase Article
Unlocked 440G-MZ switch on GuardLink doesn't respond to lock command on power up
.