Rockwell Automation Publication 440G-UM001C-EN-P - June 2019
33
Diagnostics and Troubleshooting
Chapter 6
LED Indicators Flash Red at
1 Hz
When the LEDs flash red at a 1 Hz rate, it indicates a fault condition caused by
a possible short circuit. Check that the OSSD outputs are not shorted to
ground (0V), 24V DC, or to each other. Cycle power to reset.
LED Indicators Flash Red at
4 Hz
The LED indicators flash red at a 4 Hz rate when an inconsistency is detected
with the RFID sensor. This may also happen when there is a condition that
prevents the switch from performing as expected. A number of scenarios can
cause this fault indication.
IMPORTANT
A separately mounted latch (mechanical or magnetic) is recommended to
help maintain proper alignment of the guard door.
Table 14 - Possible Causes of Flashing Red (4 Hz) Fault
Possible Cause
Solution
Actuator moved out of range
The switch will fault if the actuator moves out of range.
Check the guard door is rigid without sag. Alternatively, a separately
mounted latch (mechanical or magnetic) is recommended to help maintain
proper alignment of the guard door.
Cross talk between two switches
Adjacent switches are mounted too close to one another.
Confirm minimum distance between any two adjacent switches is 200 mm
(7.87 in.), see
.
Faulty actuator
Damage to one or to both of the reeds inside the actuator can cause
intermittent behavior of the switch.
Use a good actuator (known) with the switch to determine if the installed
actuator is working properly.
Magnet misalignment
Do not extend the locking bolt mechanically. Use of a tool to pull the bolt out
of the switch can damage or cause misalignment of the magnet at the end of
the bolt. This can cause unreliable operation of the switch.
Failure to lock
Confirm that the guard door is closed all the way so that the bolt can enter
the opening in the actuator without binding.
Failure to unlock
The locking bolt must be free to enter and withdraw from the hole in the
actuator without binding.
Check to see if there is a mechanical load applied to the guard door that
prevents the bolt from retracting.
Alternatively, use a door latch to prevent sagging of the guard door, which
can cause binding.
Bolt unable to extend or retract
Confirm the switch isn't mounted near a source of metal particles. An
accumulation of debris can prevent the bolt from extending or retracting.
Power surges can cause permanent damage to the solenoid driver circuit. The
440G-LZ is designed to be used in a NEC Class 2 circuit. Connect the 440G-LZ
to a dedicated Class 2 power supply or use electronic circuit protection (for
example, cat. no. 1692-ZRCLSS) to confirm NEC Class 2 compliance.
The switch may need to be replaced.
Lock command switched too quickly It is recommended the locking frequency is limited to a
1 Hz
maximum with
50% duty cycle (500 ms Lock, 500
ms
Unlock).
