Emerson P/N MMI-20019808 Manuel D’Utilisation

Troubleshooting

5.2

Common problems

Symptom

Resolution

Problem during configuration 
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Serial communication failed. Try again.

The Config Line LED turns red in the 
Ethernet Config Tool.

Serial communication failed. Try again.

The serial port seems to be avail-
able, but it is not possible
to connect to the EtherNet/IP 
Module.

• The serial port may be in use by another application. Exit the EtherNet/IP Module 

Configuration  Tool and close all other applications, including the ones in the system 
tray. Try again.

• Select another serial port. Try again.

Poor performance

• In the Ethernet Config Tool, right-click 

Sub-Network

 in the Navigation window and 

select 

Sub-Network Status

 to see status / diagnostic information about the Moldbus 

serial network. If the EtherNet/IP Module reports a large number of re-transmissions, 
check your cabling and/or try a lower baud rate setting for the Modbus serial network 
(if possible).

• Is the Sub-Net Monitor in the Ethernet Config Tool active? The sub-network monitor 

has a negative influence on the overall performance of the gateway, and should be 
used only when necessary.

• Is the Node Monitor in the Ethernet Config Tool active? The node monitor has a 

negative influence on the overall performance of the gateway, and should  be used 
only when necessary.

No Modbus serial network func-
tionality

• Use the Data logger functionality of the Ethernet Config Tool to record the serial data 

communication on the sub-network.

• If no data is being transmitted, use the Ethernet Config Tool to check the configura-

tion.

• If no data is being received, check the cables and connections. Also verify that the 

transmitted data is correct.

Process variables displayed or 
reported as 0

• Verify  the Modbus connection between the EtherNet/IP Module and the device.