Omron RX Series User Manual page 483

Query Frame Configuration
The format of a query frame (command) is as follows.
Header (Silent interval)
Slave address
Function code
Error check
Trailer (Silent interval)
<Slave Address>
• A serial number from 1 to 32 preset for each inverter (slave). Only the inverter that matches the slave
address specified in the query will capture that query.
• Set the slave address to 0 to perform broadcasting (distributing a query to all slave addresses at a
time).
• During a broadcast, you cannot perform data call or loop-back operation.
<Function Code>
• This specifies the function to be performed by the inverter.
• The 3G3RX-V1 Series Inverter supports the following function codes.
Function Code
Function code
01 hex
03 hex
05 hex
06 hex
08 hex
0F hex
10 hex
<Data>
• This sends the function command.
• The data format differs depending on the function code.
• The 3G3RX-V1 Series supports the following data formats used in Modbus communication.
Data name
Coil
Holding register
<Error Check>
• In Modbus communication, CRC (Cyclic Redundancy Check) is used for error checking.
• The CRC code is 16-bit data generated for any data block with a data length in 8-bit unit.
• For CRC code generation, the following generator polynomial is used: CRC-16 (X
High-function General-purpose Inverter 3G3RX-V1 User's Manual (I578-E1)
Data
Function
Read coil status
Read from holding register
Write to coil
Write to holding register
Loop-back test
Write to multiple coils
Write to multiple registers
Binary data (1 bit) that can be referenced or changed.
16-bit data that can be referenced to or changed.
8 Communications Functions
Maximum number of
data bytes per message
4
8
2
2
–
4
8
Description
Maximum number of
coils/registers per message
32 coils (in bits)
4 registers (in bytes)
1 coil (in bits)
1 register (in bytes)
–
32 coils (in bits)
4 registers (in bytes)
16 15 2
+ X + X + 1).
8 - 7
8