Chengdu Ebyte Electronic Technology Co.,Ltd.
ME31-XXAX0060_UserManual_EN
Copyright ©2012
–
2023, Chengdu Ebyte Electronic Technology Co.,Ltd
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address data.
4.2.3. Modbus TCP Protocol Data Frame Description
TCP frame format
：
Transaction ID
Protocol ID
Length
Device address
Function code
Data segment
2 Bit
2 Bit
N+2 Bit
1 Bit
1 Bit
N 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
00 00
00 06
01
02
00 00 00 04
Transaction ID
Protocol ID
Length
Device address
Function code
Data segment
4.2.4. Modbus RTU protocol data frame description
RTU frame format
：
Device address
Function code
Data segment
Check codeCRC
1 Bit
1 Bit
N Bit
2 Bit
Example: get DI status command
01
02
00 00 00 04
79 C9
Device Modbus address
Function code
Data segment
CRC check code
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.