CHAPTER 13 RS-485 COMMUNICATIONS

 Positioning data (divided)

Positioning data are 4 bytes long for each set. The positioning status, M code, and the stop timer

are configured as follows. All other items are configured in the same way as positioning data

(batch).

DATA

4bytes

00h

Positioning status

M code

DATA

4bytes

00h

Stop timer (H)

Stop timer (L)

5. Exceptional responses

The amplifier returns an exceptional response if it has not succeed the process specified by a query.

The message frame is as follows. This is common to all FC values.

Station No. 1 byte

1 byte

Exceptional

code

1 byte

16 bits (L)

CRC check

(2 bytes) (H)

(1) Function code (FC) field

Exceptional responses from slaves are returned as one is set on the MSB of the FC specified by the

query.

Query

01h

03h

05h

08h

0Fh

10h

17h

Exceptional response

81h

83h

85h

88h

8Fh

90h

97h

13-26 Modbus RTU Communications