Omega CN1166 manual Preset Single Register Write 1 Word 06 B, Loopback Diagnostic Test

D. Preset Single Register (Write 1 Word) 06 B

The message sent to the controller consists of 8 bytes: the address and function number as usual, the address of the parameter to be written, and the two-byte value to which the parameter will be set, and finally the CRC16.

Addr.	Func.	Addr. of Word			Value		CRC16
	6	HI	LO	HI		LO	HI	LO

The normal response is to echo the message in its entirety.

E. Loopback Diagnostic Test 08

The controller is sent an 8 byte message consisting of the usual preamble, a two-byte diagnostic code, and two bytes of data, followed by the CRC16.

Addr.	Func.	Diag. Code			Value		CRC16
	8	HI	LO	HI		LO	HI	LO

Full MODBUS support in this area is not appropriate - consequently, the only Diagnostic Code supported is code 00. In response to the message, the controller must echo the message received exactly.

F. Preset Multiple Registers (Write n Words) 16 B

This message consists of eleven bytes. Only one parameter may be written at a time, even though this function number is supported. The preamble is followed by the address of the parameter to be written, and then a two-byte word count (always set to 1) and a single-byte byte count (always set to 2). Finally, the value to be written is followed by the CRC16.

Addr.	Func.	Addr. of Word		No. of Words		Count
	16	HI	LO	0	1	2

	Value	CRC16
HI	LO	HI	LO

The controller normally responds with a eight-byte reply, as follows:

Addr.	Func.	Addr. of Word		No. of Words		CRC16
	16	HI	LO	0	1	HI	LO

4-4 Volume II O077-4