CHAPTER 13 RS-485 COMMUNICATIONS

13

(2) Response message from the amplifier

Station No.

1 byte

FC

1 byte

･･･ 10h

Information

Address

No. of

registers

CRC check

2 bytes

2 bytes

16 bits

(2 bytes)

(H) ･･･ Specified address

(L)

(H) ･･･ Number of sets of actually written data, m × 2

* The positioning data are m × 10.

(L)

* Cannot write in to nonexistent data.

(L)

(H)

(3) Message examples

PA2_19: shows a message example to enter 200000 to a preset position.

<Query example>

Station No.

FC

Address

No. of registers

Information

No. of data

bytes

Data 1

CRC check

1 byte

1 byte

2 bytes

2 bytes

1 byte

4 bytes

16 bits

(2 bytes)

01 ･･･ When the amplifier station no. is "1".

10

41 ･･･ Specify 4112h as the address of PA2_19.

12

00 ･･･ Specify 0002h as the number of data 1×2.

02

04 ･･･ 1×4 = 04h

00 ･･･ Specify 200000 = 00030D40h.

03

0D

Specify data 1 = FFFCF2C0h for -20000.

40

BA

49

<Response message example>

Station No.

1 byte 01

FC

1 byte 10

Information

Address

No. of registers

2 bytes

2 bytes

41

12

00

02

CRC check

16 bits F5

(2 bytes) F1

13-8 Modbus RTU Communications