CPU LEDs

Use the safety-related LEDs on the front face of the CPU, as described below, to diagnose the state of the PAC.

In the Modicon M580 Hot Standby, System Planning Guide for Frequently Used Architectures, refer to the topic LED Diagnostics for M580 Hot Standby CPUs for information on how to diagnose the redundancy-related LEDs, including [A], [B], [PRIM], [STBY], and [REMOTE RUN].

NOTE: LEDs are not reliable indicators and cannot be guaranteed to provide accurate information. Use them only for general diagnostics during commissioning or troubleshooting.

PAC State

LED Names and Colors:

RUN

ERR

IO1

ETH MS

ETH NS

DL

SRUN

SMOD

Green

Red

Red

Green/Red

Green/Red

Green

Green

Green

Power OFF

Power ON

  • Autotest

Not configured

No cable plugged and connected to another powered device

Otherwise

Configured:

  • No external error detected

–

–

  • External error detected

–

–

–

–

  • No Ethernet link, including the Ethernet backplane

–

–

  • Duplicate IP address

–

–

–

  • STOP state

Detected error on I/O module, channel or configuration

Not connected

SAFE task running

OR

SAFE task stopped

Safety mode

OR

Maintenance mode

No error detected on configured input/output

Connected

No cable

  • RUN state

–

Not connected

SAFE task running

OR

SAFE task stopped

Safety mode

OR

Maintenance mode

Connected

No cable

HALT state (recoverable error detected)

–

SAFE task running

Safety mode

SAFE task stopped

Maintenance mode

SAFE state (non-recoverable error detected)

OS update

1. Not all errors detected for a safety I/O module are reported via LEDs. Check the DDDTs for safety I/O modules for additional information.

Legend:

Symbol

Description

  

Symbol

Description

  

Symbol

Description

Steady Green

  

Steady Red

  

OFF

Blinking Green (500 ms ON, 500 ms OFF)

Blinking Red (500 ms ON, 500 ms OFF)

–

Not Applicable