Message Configuration - Hitachi WJ Series User Manual

Chapter 11
11.1.4

Message Configuration

 The command message sent from the master to the slave is called "Query", and the response
A
message from the slave is called "Response". The transmission format of "Query" and "Response"
is shown below.
Slave address
Function code
Query data
Error checking (CRC-16)
■ (1) Slave address (communication node address)
 The slave address is a number in the range of 1 to 247 set in advance for each inverter (slave).
(The query is fetched only by the inverter that matches the slave address of the query.)
 If "0" is specified as the slave address of the destination on the master side, broadcast to all
stations can be performed. For broadcast, all slaves receive data, but do not return a response.
 During broadcast, data cannot be read or looped back.
 In Modbus specification, the slave address is 1 to 247. However, if slave addresses 250 to 254
are used on the master side, broadcasting can be performed only for a specific slave address.
(Slaves do not respond, and broadcast is valid only for write commands (05h, 06h, 0Fh, 10h).)
■ (2) Function code
 The function executed by the inverter is specified by the function code.
 The corresponding function code is shown below.
Function code
01h Read coil status
03h Read multiple registers
05h Write coil
06h Write holding registers
08h Loop-back Test
0Fh Write multiple coils
10h Write multiple registers
Read/write multiple holding
17h
registers
Query
Slave address
250 (FAh) Broadcast to slave addresses 01 to 09
251 (FBh) Broadcast to slave addresses 10 to 19
252 (FCh) Broadcast to slave addresses 20 to 29
253 (FDh) Broadcast to slave addresses 30 to 39
254 (FEh) Broadcast to slave addresses 40 to 247
Function
11-1-5
RS485 Communication
Response
Slave address for checking
Function code for checking
Response data
Error checking (CRC-16)
Destination
Max. data bytes
handled by 1 massage
4
32
2
2
-
4
32
32/32
Max. number of data
handled by 1 message
32 coils (in bits)
16 registers (in bytes)
1 coil (in bits)
1 register (in bytes)
-
32 coils (in bits)
16 registers (in bytes)
16/16 registers (in bytes)