Perle Systems 5500161-40 manual Successful Response Format, Unsuccessful Response Format

Accessing I/O Data Via TruePort

Successful Response Format

Byte(s)	# of Bytes	Value
1	1	Command code (from request).
2	2	Starting register number (see A4/T4 Registers on page 280,
		A4D2/A4R2 Registers on page 281, or D4/D2R2 Registers on page 282
		for this value) from request.
4	2	Number of registers written.

Unsuccessful Response Format

Byte(s)	# of Bytes	Value
1	1	Command that this is a response to. If an error has been detected, the
		command value will have the high bit set (OR with 0x80). For
		example: The Command is 0x10, so the command field in the response
		would be 0x90.
1	1	Error code, see Error Codes on page 289.

Example 1: Turn on the first relay on a D2R2 unit.

The first relay (R1) is a digital out coil register with a decimal value of 6659 (hex 0x1A03). Request: 0x0F 0x1A 0x03 0x00 0x01 0x01 0x01

Response: 0x0F 0x1A 0x03 0x00 0x01

Example 2: Turn on the first and second relay on a D2R2 unit.

The first relay (R1) is a digital out coil register with a decimal value of 6659 (hex 0x1A03). Request: 0x0F 0x1A 0x03 0x00 0x02 0x01 0x03 (03 = “00000011” which sets R1 and R2 to 1) Response: 0x0F 0x1A 0x03 0x00 0x02

Note: When reading or writing consecutive “Boolean” (coils) registers, the values of the registers are combined into a single byte as shown by the example above. Two registers (coils) are being written but the length of the data is 1 byte. The one byte contains the value for both registers as follows:

288 IOLAN SDS/SCS/STS/MDC User’s Guide, Version 4.0