Module Status Indicator And Display - Allen-Bradley ControlLogix User Manual

Troubleshooting
The 1756-CNB and 1756-CNBR modules are provided with the LED
diagnostic indicators shown below. The diagnostics provided by these
indicators is described in the following sections.
1756-CNB 1756-CNBR

Module Status Indicator and Display

LED Display
Cause
OK
Off None Module not communicating
due to a power supply fault or
internal fault.
Red INIT Module is initializing
POST Module is running Power-On
Self Test (POST)
X Module failed POST because
the RAM test failed.
module status display and
module status display and network
network addressdescribed
on page 14
address
module status indicator
module status indicator (red or
(red or
green)
green)described on
See pages 12-1 to 12-3.
page 11
ControlNet status indicator(s)
See pages 12-3 to 12-4.
Action
1. Check the power supply.
2. Check the cable connectors.
3. Make sure the module is firmly
seated in the chassis.
4. If the indicator remains off,
replace the module.
None required.
Replace the module.
12
Chapter
20958-M
1756-6.5.3 - December 1999