Instruction Manual

3-3

IM 77J04J11-01E 1st Edition : 2006.08.25-00

3.1.2 Configuration of Response

Responses from the M Series with respect to a command sent from the higher-level device

consist of the following elements, which differ depending on the condition of communica-

tion; normal or failure.

1) Normal Communication

If communication succeeded, a character string "OK" is returned with the data correspond-

ing to a command.

Number of Bytes Variable length12 22 211

Element STX Address

number

(ADR)

CPU

number

OK Parameter data Checksum ETX CR

2) In the Event of Failure

If communication failed, a character string "ER" is returned with error codes (EC1 and

EC2). (See subsection 3.1.3, "Response Error Codes.")

• No response is returned in case of an error in address number specification or CPU

number specification.

• If ETX in a command cannot be received, a response may not be returned.

Note: As a countermeasure, provide a timeout process in the communication functions of the higher-level device or in

communication programs.

Number of Bytes 1 2 2 2 2 2 3 2 1 1

Element STX ER EC1 EC2 Command Checksum ETX CRAddress

number

(ADR)

CPU

number