Appendix A MODBUS Communication Protocol
Shenzhen Hpmont Technology Co., Ltd.
-70-
HD3Z Series User Manual V1.2
For example:
To read the slave internal register F00.08 = 50.00Hz of No.1 address:
Address Parameter Register address
Read char no.
Checksum
Command frame 0x01
0x03
0x00
0x08
0x00
0x01
0x05
0xC8
Address Parameter Response byte
Content of register
Checksum
Response frame
0x01
0x03
0x02
0x13
0x88
0xB5
0x12
2.
Scaling of Drive Transmitting Values
Except the parameters of the remarks, all other function codes can define the scaling relationship of
the specified function code via referring the manual’s minimum unit.
Remarks:
1. 0-2000 of F04.03, F16.05, F16.08, F16.22, F16.24 corresponds to -1000 - +1000.
2. Communication data 0-16000 of status parameter 0x3318 corresponds to -8000 - +8000.
3. Communication dats 0-2000 of status parameter (AI2 input voltage, AI2 input voltage (after calculating),
process PID setting, process PID feedback, process PID tolerance, process PID integral and process PID
output correspond to -1000 - +1000.
3.
Protocol Function
Supported Function
MODBUS protocol supports the below parameter operation:
Supported function
Code
Instructions
To read function parameters and status parameter
0x03
To rewrite single function parameter or control
parameter
0x06
Set by F17.09
0x41
Not saved at power off
To rewrite numbers of function parameters or
control parameters
0x10
Set by F17.09
0x43
Saved at power off
To Read function Parameters and Status Parameter
Function code 0x03, command frame and response frame are in below table (take RTU as an example).
Command frame Address
Code
Starting register address No. of register
CRC / LRC checking
Data frame bytes
1
1
2
2
2/1
Value or range
0 - 247
0x03
0x0000 - 0xFFFF
0x0001 - 0x000C
Response frame
Address
Code
Read byte no.
Register content
CRC / LRC checking
Data frame bytes
1
1
1
2*no. of registers
2/1
Value or range
1 - 247
0x03
2*no. of registers