B.2.2 memobus rtu mode, Coil status read – Yaskawa MP920 Communications Module User Manual

Page 268

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B.2 MEMOBUS Messages

B-19

B

„

List of MEMOBUS Commands

The commands that make up the MEMOBUS messages are identified by a function code,

and have the functions shown in the following table.

B.2.2

MEMOBUS RTU Mode

„

Coil Status Read

Function Code

Function

MEMOBUS

(RTU)

MEMOBUS

(ASCII)

01H

Coil status read

2,000 points

976 points

02H

Input relay status read

2,000 points

976 points

03H

Holding register write

125 words

61 words

04H

Input register read

125 words

61 words

05H

Single coil status change

1 point

1 point

06H

Single holding register write

1 word

1 word

08H

Loopback test

0FH

Multiple coil status change

800 points

800 points

10H

Multiple holding register write

100 words

59 words

The function code is 01H when the coil status is read.

Set the leading address of the coils to be read.

Set the number of coils to read.

Error check

Slave address

Function code: 01H

Start No.

No. of colis

CRC-16

(L)

(H)

(L)

(H)

(L)

(H)

Command

7

0

Slave address

Function code: 01H

No. of data items

Status of first 8 coils

Status of next 8 coils

Status of next 8 coils

CRC-16

(L)

(H)

The function code is 01H when the coil status is read.

The byte length of the read data is returned.

The read data contents are returned.

Error check

Response

7

0

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