2. MODBUS/TCP PROTOCOL
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(2) Usage example
The following shows a setting example of when the diagnosis function is used.
Query Message
Transaction
Identifier
Protocol
Identifier
Length Field
Unit
Identifier
Function
Sub Function
Data
H L H L
16
bits 0000h 0006h FFh 08h 00h 00h 12h 34h
Set the following values to each Query Message.
Message field
Description
Transaction Identifier
(Transaction identifier)
Set any value.
Protocol Identifier
(Protocol identifier)
Set "0000h".
Length Field (Message length)
Set "0006h".
Unit Identifier (Unit identifier)
Set "FFh".
Function (Function field)
Set "08h".
Sub Function (Sub function)
Set "0000h".
Data (Data)
When setting 1234h, set values as follows:
H: "12h"
L: "34h"
Response Message
Transaction
Identifier
Protocol
Identifier
Length Field
Unit
Identifier
Function
Sub Function
Data
H L H L
16
bits 0000h 0006h FFh 08h 00h 00h 12h 34h
The following shows the information in each Response Message.
Message field
Description
Transaction Identifier
(Transaction identifier)
Transaction Identifier received from the client (controller) is copied and returned.
Protocol Identifier
(Protocol identifier)
The value "0000h" is returned.
Length Field (Message length)
The byte length from Unit Identifier to Data is returned.
Unit Identifier (Unit identifier)
Unit Identifier received from the client (controller) is copied and returned.
Function (Function field)
When the message was received without errors, "08h" is returned.
Sub Function (Sub function)
The value "0000h" is returned.
Data (Data)
The value "1234h" set in the Query Message is returned.
H: "12h"
L: "34h"
Summary of Contents for MELSERVO-JE MR-JE-C
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