22 Rockwell Automation Publication 1791ES-UM001G-EN-P - November 2016
Chapter 1 Safety Function Operation
Table 3 shows the expected behavior of the muting status bits. Keep these
points in mind as well:
• When power is applied to the module, and a test output capable of
operating as a muting output remains commanded off, the muting status
defaults to on.
This bit operation is designed to help prevent erroneous muting
instruction faults from the GuardLogix controller. This bit status is not
the true indication of a burned-out lamp.
• If a muting lamp circuit is open when power is applied to the module,
the condition is detected when the test output is commanded on.
• When a lamp burns out and is replaced, the fault (muting status bit)
returns to the normal condition, independent of the state of the test
output.
IMPORTANT Before checking the state of the corresponding muting status, make
sure that the test output is commanded on. Once the test output is
commanded on, a maximum time of 6 seconds is required for the
module to detect a burned-out lamp.
Table 3 - Muting Status Bit Operation
Test Output
Commanded
State
Lamp Condition Muting
Status
Bit
Description
ON Bad (open circuit) 0 Repair lamp.
ON Good 1 Normal condition. Lamp is operating properly.
OFF Bad (open circuit) 0 If lamp remains off after a test output capable of operating
as a muting output is cycled, repair the lamp.
OFF Good 1 Normal condition.
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