Goodrive3000 series medium voltage VFD
Moudbus protocol
-207-
Example 2: Set the max. output frequency to 100 Hz for the VFD with the address of 03H.
Function
code
Name
Description
Setting range
Default
P00.03
Max. output
frequency
P00.04
–400.00Hz
P00.04
–400.00
50.00Hz
See the figures behind the radix point, the fieldbus ratio value of max. output frequency (P00.03) is 100. 100Hz timed by
100 is 10000 and the corresponding hex is 2710H.
The command transmitted from the master is as follows:
Parameter
address
VFD
address
Write
command
CRC
Parameter
data
03
06
00 03
27 10
62 14
If the operation is successful, the following response is returned (same as the command sent from the master):
Parameter
address
VFD
address
Write
command
CRC
Parameter
data
03
06
00 03
27 10
62 14
Note: In the preceding command description, spaces are added to a command just for explanatory purposes. In
practical applications, no space is required in the commands.
8.4.7.3 Example of MODBUS communication commissioning
A PC is used as the host, an RS232-RS485 converter is used for signal conversion, and the PC serial port used by the
converter is COM1 (an RS232 port). The host controller commissioning software is the serial port commissioning assistant
Commix, which can be downloaded from the Internet. Download a version that can automatically execute the CRC check
function. The following figure shows the interface of Commix.
First, set the serial port to
COM1
. Then, set the baud rate consistently with P14.01. The data bits, check bits, and end bits
must be set consistently with P14.02. If the RTU mode is selected, you need to select the hexadecimal form
Input HEX
.
To set the software to automatically execute the CRC function, you need to select
ModbusRTU
, select
CRC16
(MODBUSRTU)
, and set the start byte to
1
. After the auto CRC check function is enabled, do not enter CRC information in
commands. Otherwise, command errors may occur due to repeated CRC check.
The commissioning command to set the VFD whose address is 03H to be forward running is as follows:
Parameter
address
VFD
address
Write
command
CRC
Forward running
03
06
20 00
00 01
42 28
Note:
Set the address (P14.00) of the VFD to 03.
Set "Channel of running commands" (P00.01) to "Communication", and set "Communication channel of
running commands" (P00.02) to the Modbus channel.