Delta DVP-ES2/EX2/SS2/SA2/SX2/SE manual Exception response

DVP - ES2/EX2/SS2/SA2/SX2/SE Operation Manual - Programming

Exception response:

The PLC is expected to return a normal response after receiving command messages from the master device. The following table depicts the conditions that either a no response or an error response is replied to the master device.

1.The PLC did not receive a valid message due to a communication error; thus the PLC has no response. The master device will eventually process a timeout condition.

2.The PLC receives a valid message without a communication error, but cannot accommodate it, an exception response will return to the master device. In the exception response, the most significant bit of the original command code is set to 1, and an exception code explaining the condition that caused the exception is returned.

An example of exception response of command code 01H and exception 02H: Sent message:

	Field Name	ASCII	Hex
	STX	:	3A
	Slave Address	01	30 31
	Command code	01	30 31
	Starting Address Hi	04	30 34
	Starting Address Lo	00	30 30
	Number of Points Hi	00	30 30
	Number of Points Lo	10	31 30
	Error Check (LRC)	EA	45 41
	END	CR LF	0D 0A
Feedback message:
	Field Name	ASCII	Hex
	STX	:	3A
	Slave Address	01	30 31
	Function	81	38 31
	Exception Code	02	30 32
	Error Check (LRC)	7C	37 43
	END	CR LF	0D 0A

4 - 6