Delta DVP-ES2/EX2/SS2/SA2/SX2/SE Communication Protocol RTU mode, Exception Explanation Code

4 . Communications

Exception	Explanation:
code:

01Illegal command code:

The command code received in the command message is invalid for PLC.

02Illegal device address:

The device address received in the command message is invalid for PLC.

03Illegal device content:

The data received in the command message is invalid for PLC.

1. Checksum Error

- Check if the checksum is correct

072. Illegal command messages

-The command message is too short.

-Length command message is out of range.

4.3Communication Protocol RTU mode

Communication Data Structure

9600 (Baud rate), 8 (data bits), EVEN (Parity), 1 (Start bit), 1 (Stop bit)

START	No data input ≥ 10 ms
Address	Communication Address: the 8-bit binary address
Command code	Command Code: the 8-bit binary address
DATA (n-1)	Data Contents:
…….
	n × 8-bit BIN data, n≦202
DATA 0
CRC CHK Low	CRC Checksum:
CRC CHK High	The 16-bit CRC checksum is composed of 2 8-bit binary codes
END	No data input ≥ 10 ms

4.3.1 Address (Communication Address)

Valid communication addresses are in the range of 0~254. Communication address equals to 0 means broadcast to all PLCs. PLC will not respond to a broadcast message. PLC will reply a normal message to the master device when communication address is not 0.

Example, communication address should be set to 10 (Hex) when communicating with a PLC with address 16 (Dec) (16 in Decimal = 10 in Hex)

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