Advanced Modbus Settings

Setting

Value

Notes

 

Enable (Default)

Select Enable when

Auto Slave Unit ID

multiple Modbus devices

 

 

are accessible at the same

Disable

 

 

IP address.

1

 

 

 

 

10 to 3000 ms

This parameter is active

Character Timeout

when the attached serial

(default = 100 ms)

device is set to

 

 

Modbus/RTU.2

 

 

Allows you to configure

 

10 to 3000 ms

the message timeout for

Message Timeout

communication between

(default = 1000 ms)

 

connected Ethernet or

 

 

 

 

serial Modbus devices.

 

 

This parameter is active

 

 

when the Modbus

Modbus/TCP Exception

default = 502

Gateway connects a

Modbus/TCP Master with

 

 

 

 

Modbus serial slave

 

 

devices.3

 

Additional Information

1.Modbus/TCP protocol contains a “Unit ID” field to identify multiple Modbus slave devices accessible at a single IP address. When the Modbus/TCP command contains a Unit ID, the Modbus Gateway can pass the Unit ID to Modbus serial devices. This allows you to link to multiple serial devices with a Modbus Gateway. Some PLCs assume that each IP connects to only one device. In these cases, the Unit ID can be set “0,” but you must manually assign a Unit ID (between 1 and 247) to the connected serial device. However, each Modbus Gateway can connect to only one serial device.

This setting is valid when [Attached Serial Device type] is set to [Modbus RTU Slave ] or [Modbus ASCII Slave].

Enable: Uses the Unit ID in the Modbus/TCP packet. This is the default setting.

Disable: Uses the predefined Unit ID instead of Modbus/TCP’s.

ID:

The predefined Unit ID value, ranging from 1 to 247, which is valid

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Moxa Technologies 6110 user manual IP address