8-2
Section
Troubleshooting with the LED Indicators
109
8-2
Troubleshooting with the LED Indicators
8-2-1 Meaning of the LED Indicators
The DeviceNet Interface Unit has 2 two-color (red or green) LED indicators.
MS (Module Status) LED:
Indicates the PT’s status as a Slave.
NS (Network Status) LED:
Indicates the status of the network.
The following table shows the functions of the LED indicators. The color and sta-
tus of the MS and NS indicators can be used to troubleshoot errors.
LED
Name
Color
Status
Indicated condition
Meaning
MS
Module status
Green
Lit
Normal status
Normal Unit condition
Flashing
Not set yet
Switch settings are being read.
Red
Lit
Fatal error
Unit hardware error (Watchdog Timer error)
Flashing
Non-fatal error
Minor error such as incorrect switch settings
---
Not lit
No power being supplied
•
Power is not being supplied to Slave Units.
•
Waiting for initialization to start.
•
Unit is being reset.
NS
Network status
Green
Lit
Online, communications
established
Normal network condition (communications
established)
Flashing
Online, communications
not established
Normal network condition but
communications are not established
Red
Lit
Fatal communications
error
Communications error (The Unit detected
an error which makes communications
through the network impossible.)
•
Node number duplication
•
Bus off detected
•
Network power supply error
Flashing
Non-fatal
communications error
Communications timeout
---
Not lit
Offline or power supply
OFF
•
Waiting for completion of the Master’s node
number duplication check
•
Incorrect switch settings (such as an incor-
rect communications speed setting)
•
Faulty network communications cable
•
Power supply OFF
