Allen-Bradley 1734-OBV2S

Rockwell Automation Publication 1734-UM013N-EN-P - September 2017 45
Safety Inputs, Safety Outputs and Safety Data Chapter 2
This bit operation is designed to help prevent erroneous muting
instruction faults from the GuardLogix controller. This bit status is not
always 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.
I/O Status Data
In addition to I/O data, the module provides status data for monitoring the I/O
circuits. The status includes diagnostic data that the controllers can read with
1 = ON/Normal and 0 = OFF/Fault/Alarm.
IMPORTANT
Before checking the state of the corresponding muting status, be 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 4 - 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 T1/T3 output cycled, repair lamp.
OFF Good 1 Normal condition.