Rockwell Automation 1771-P4S_P6S_P4S1_P6S1 Power Supply Modules Installation Instructions - Manual (Page 9)

Publication 1771-IN079A-EN-P - June 2002
Allen-Bradley Power Supply Modules 9
Interpreting the Indicators Your power supply has an indicator located in the upper half of the module
front panel labeled P/S ACTIVE. Refer to the table below for descriptions
of possible conditions.
Troubleshooting a Single
Power Supply If you have a single power supply installed in the I/O chassis and its P/S
ACTIVE indicator is off, verify the ground connection to the supply; then
follow the flow chart below.
Table 4 Interpreting the P/S ACTIVE Indicator
If the indicator is: Then:
ON The power supply (and any supply connected thru a paralleling cable ) is
operating normally. However, it could still have a poor connection to the
backplane.
OFF The power supply has detected one of the following:
• dc overvoltage (the supply shuts down)
• dc undervoltage (the supply shuts down)
• dc overcurrent (the supply shuts down)
• power switch is turned off (the supply is turned off)
• ac undervoltage
• the paralleled supply is shut down
With ac undervoltage or a paralleled supply shut down, the supply will
attempt to generate the output. When dc limits ar exceeded, the supply
shuts down until you turn power off (for 5s minimum) and then turn it
back on.