Fuji Electric ALPHA5 Smart - Page 499

CHAPTER 13 RS-485 COMMUNICATIONS
Modbus RTU Communications 13-11
13
<Response message example>
Station No. 1 byte
01
FC 1 byte
05
02
Address
2 bytes
08
FF
Information
No. of coil data
2 bytes
00
0C
CRC check
16 bits
(2 bytes)
40
 FC 0Fh (Write in coil data)
(1) Query from the master
Station No. 1 byte
FC 1 byte
･･･
0Fh
(H)
Address
2 bytes
(L)
･･･
Specify the coil address.
* For the addresses, refer to the table 13-4.
(H)
No. of coil data
2 bytes
(L)
･･･
Specify the number of coils n.
* Up to 16 pcs.
No. of data bytes
1 byte
･･･
The value (N) obtained from n/8 and by
rounding up decimal
Data 1
1 byte (8 bits)
~
~
Information
Data N
1 byte (8 bits)
･･･
n pcs of data read out from a specified
address.
* 1 pcs = 1 bit (1 byte by 8 pcs)
* Allocated from LSB in order.
(L)
CRC check
16 bits
(2 bytes)
(H)
(2) Response message from the amplifier
Station No. 1 byte
FC 1 byte
･･･
05h
(H)
Address
2 bytes
(L)
･･･
Specified address.
(H)
Information
No. of coil data
2 bytes
(L)
･･･
The number of coils actually written in is m pcs.
* Cannot write in to nonexistent coil data.
(L)
CRC check
16 bits
(2 bytes)
(H)