Frequency Inverter ST600 Series High-Performance Multifunction VFD Communication protocol
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"Default value". If there are n decimals in the value, the fieldbus scale m is the power n of 10. Take the
following table as an example, m is 10.
0.0–3600.0s (valid when the ones place of
P01.19 is 2)
0: Restart is disabled
1: Restart is enabled
The value specified in "Description" or "Default value" contains one decimal, so the fieldbus scale is
10. If the value received by the controlling computer is 50, the value of "Wake-up-from-sleep delay" of
the VFD is 5.0 (5.0=50/10).
To set the "Wake-up-from-sleep delay" to 5.0s through Modbus communication, you need first to
multiply 5.0 by 10 according to the scale to obtain an integer 50, that is, 32H in the hexadecimal form,
and then transmit the following write command:
VFD
address
Write
command
Parameter
address
Parameter
data
CRC
01 06 01 14 00 32 49 E7
After receiving the command, the VFD converts 50 into 5.0 based on the fieldbus scale, and then sets
"Wake-up-from-sleep delay" to 5.0s.
For another example, after the controlling computer transmits the "Wake-up-from-sleep delay"
parameter read command, the master receives the following response from the VFD:
VFD
address
Read
command
Parameter
data
CRC
2-byte
data
01 03 02 00 32 39 91
The parameter data is 0032H, that is, 50, so 5.0 is obtained based on the fieldbus scale (50/10=5.0).
In this case, the master identifies that the "Wake-up-from-sleep delay" is 5.0s.
9.4.6 Error message response
Operation errors may occur in communication-based control. For example, some parameters can only
be read, but a write command is transmitted. In this case, the VFD returns an error message response.
Error message responses are transmitted by the VFD to the master. The following table describes the
codes and definitions of the error message responses.
The command code received by the controlling computer is not allowed to be
executed. The possible causes are as follows:
⚫ The function code is applicable only on new devices and is not implemented
on this device.
⚫ The slave is in the faulty state when processing this request.
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