Goodrive270 series VFD for fan and pump Communication protocol
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The following table describes the encoding rules of device codes (corresponding to the identification
code 2103H of the VFD).
9.4.5 Fieldbus scale
In practical applications, communication data is represented in the hexadecimal form, but
hexadecimal values cannot represent decimals. For example, 50.12 Hz cannot be represented in the
hexadecimal form. In such cases, multiply 50.12 by 100 to obtain an integer 5012, and then 50.12 can
be represented as 1394H in the hexadecimal form (5012 in the decimal form).
In the process of multiplying a non-integer by a multiple to obtain an integer, the multiple is referred to
as a fieldbus scale.
The fieldbus scale depends on the number of decimal places in the value specified in "Setting range"
or "Default". If there are n (for example, 1) decimal places in the value, the fieldbus scale m (then
m=10) is the result of 10 to the power of n. Take the following table as an example.
0.0–3600.0s (valid
when P01.15 is 2)
Power-off restart
selection
0: Disable restart
1: Enable restart
The value specified in "Setting range" or "Default" contains one decimal place, and therefore the
fieldbus scale is 10. If the value received by the upper computer is 50, the value of
"Wake-up-from-sleep delay" of the VFD is 5.0 (5.0=50/10).
To set "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 send 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 upper computer sends the "Wake-up-from-sleep delay" parameter
read command, the master receives the following response from the VFD:
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