Fuji Electric ALPHA7, User Manual

Page: 547 / 662

CHAPTER 13 MODBUS RTU COMMUNICATION
13-8
Transmission Protocol
13
13.3.3 Function codes (FC)
The six types of FC below are supported:
Category FC Function Broadcasting
Data manipulation 03h (3) Read out various data Disabled
10h (16) Write in various data Enabled
17h (23) Read out/write in various data Enabled*
Coil data manipulation 01h (1) Read out coil data Disabled
05h (5) Write in single coil data Enabled
0Fh (15) Write in coil data Enabled
Maintenance 08h (8) Echo back Disabled
*Queries from master are accepted, and response messages are not returned.
 FC 03h (Readout of various data)
(1) Query from the master
Station No. 1 byte
FC 1 byte
･･･
03h
Information
Address 2 bytes
(H)
･･･
Specify the data address.
* For the addresses, refer to the table 13-1.
(L)
No. of registers 2 bytes
(H)
･･･
Specify the number of sets of data n × 2 .
* Specify n × 10 on the positioning data.
(L)
CRC check
16 bits
(2
bytes)
(L) * The max number of positioning data is
9, and 45 for others.
(H)
(2) Response message from the amplifier
Station No. 1 byte
FC 1 byte ･･･ 03h
Information
No. of data
bytes
1 byte
･･･
n × 4
* The positioning data are n × 20 .
Data 1 4 bytes
(HH)
･･･
Readout data for n sets from the specified
address
* The positioning data are 20 bytes per
data.
* For the data format, refer to [Table 13-1].
* "0" is returned to nonexistent data.
(HL)
(LH)
(LL)
~ ~
Data n 4 bytes
(HH)
(HL)
(LH)
(LL)
CRC check
16 bits
(2
bytes)
(L)
(H)