Allen-Bradley ControlLogix User Manual

1756-6.5.3 - December 1999
Chapter 12
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.
Module Status Indicator and Display
LED Display
Cause Action
Off None Module not communicating
due to a power supply fault or
internal fault.
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.
Red INIT Module is initializing None required.
POST Module is running Power-On
Self Test (POST)
X Module failed POST because
the RAM test failed.
Replace the module.
1756-CNB 1756-CNBR
20958-M
ControlNet status indicator(s)
module status display and
network addressdescribed
on page 14
module status indicator
(red or
green)described on
page 11
module status display and network
address
module status indicator (red or
green)
See pages 12-1 to 12-3.
See pages 12-3 to 12-4.
OK

Allen-Bradley ControlLogix Specifications

General

Communication	EtherNet/IP, ControlNet, DeviceNet, DH+
I/O Capacity	Up to 128, 000 I/O points (varies by configuration)
Redundancy	Supported (with specific modules)
Programming Software	Rockwell Automation Studio 5000 Logix Designer
Operating Temperature	0°C to 60°C (32°F to 140°F)
Programming Languages	Ladder Logic, Function Block Diagram, Structured Text, Sequential Function Chart
Modularity	Yes
Certifications	UL, CE
Processor Type	Multiple options available, including standard, safety, and extreme environment processors
Power Supply	Multiple options available, including standard and redundant power supplies with various voltage ranges (e.g., 24V DC, 120/240V AC)