Modbus Tcp Protocol Data Frame Description; Modbus Rtu Protocol Data Frame Description; Active Upload - Ebyte ME31-XXAX0060 User Manual

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address data.

4.2.3. Modbus TCP Protocol Data Frame Description

TCP frame format：
Transaction ID Protocol ID
2 Bit
 Transaction ID: It can be understood as the serial number of the message. Generally, 1 is added after each
communication to distinguish different communication data messages.
 Protocol identifier: 00 00 means Modbus TCP protocol.
 Length: Indicates the length of the next data in bytes.
Example: get DI status
01 00
Transaction ID Protocol ID

4.2.4. Modbus RTU protocol data frame description

RTU frame format：
Device address
1 Bit
Example: get DI status command
01
Device Modbus address

4.3 Active upload

The device supports the function of uploading analog input values at regular intervals. Setting the value of the
corresponding register can control the interval time and whether to upload.
Devices with digital input will actively upload once after successfully connecting to the server, and then the digital
input will be uploaded following the status change. Devices with analog input will report the status of analog input
according to the configured active upload time period (the configuration period is 1-65535 ).
When it is set to 0, the upload is disabled; if it is set to other positive integer value N, the upload will be performed
at intervals of N seconds.
[Note] The device can only be valid if it is configured in client mode, and the register value is non-zero to enable
active upload.
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Length
2 Bit N+2 Bit
00 00 00 06
Length
Function code
1 Bit
02
Function code
Device address Function code
1 Bit 1 Bit
01
Device address Function code
Data segment
N Bit
00 00 00 04
Data segment
ME31-XXAX0060_UserManual_EN
Data segment
N Bit
02 00 00 00 04
Data segment
Check codeCRC
2 Bit
79 C9
CRC check code
16