Delta DVP-ES2/EX2/SS2/SA2/SX2/SE manual Start/End

3. Instruction Set

		Field Name			Descriptions
		Address		Communication address: n 8-bit binary
		Function		Function code: n 8-bit binary
		DATA (n-1)		Data:
		…….
				n × 8-bit data
		DATA 0
		CRC CHK Low		CRC checksum:
		CRC CHK High		16-bit CRC consists of 2 8-bit binary data
		END		Refer to the following explanation
START/END:
	RTU Timeout Timer:
		Baud rate(bps)	RTU timeout timer (ms)		Baud rate (bps)	RTU timeout timer (ms)
		300	40		9,600	2
		600	21		19,200	1
		1,200	10		38,400	1
		2,400	5		57,600	1
		4,800	3		115,200	1
Address:

00 H: Broadcasting to all drives (Broadcast)

01 H: toward the drive at address 01

0F H: toward the drive at address 15

10 H: toward the drive at address 16

… and so on, max. address: 254 (‘FE’)

Function code:

03 H: read contents from multiple registers

06 H: write one word into single register

10 H: write contents to multiple registers Data characters:

The data sent by the user

CRC checksum: Starting from Address and ending at Data Content. The calculation is as follows: Step 1: Set the 16-bit register (CRC register) = FFFFH

Step 2: Operate XOR on the first 8-bit message (Address) and the lower 8 bits of CRC register. Store the result in the CRC register.

Step 3: Right shift CRC register for a bit and fill “0” into the highest bit.

Step 4: Check the lowest bit (bit 0) of the shifted value. If bit 0 is 0, fill in the new value obtained at step 3 to CRC register; if bit 0 is NOT 0, operate XOR on A001H and the shifted value and store the result in the CRC register.

Step 5: Repeat step 3 – 4 to finish all operation on all the 8 bits.

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