Fieldbus Scale; Error Message Response - INVT Goodrive350 Series Operation Manual

Goodrive350 series high-performance multi-function inverter

9.4.6 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, we can multiply 50.12 by 100 to obtain an integer 5012, and then
50.12 can be represented as 1394H (5012 in the decimal form) in the hexadecimal 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 decimals in the value specified in "Detailed parameter
description" or "Default value". If there are n decimals in the value, the fieldbus scale m is the
th
-power of 10. Take the following table as an example, m is 10.
n
Function
code
P01.20
P01.21
The value specified in "Detailed parameter description" or "Default value" contains one decimal, so
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 inverter 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:
01
Inverter
address
After receiving the command, the inverter 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 transmits the "Wake-up-from-sleep delay" parameter
read command, the master receives the following response from the inverter:
01
Inverter
address
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.

9.4.7 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 inverter returns an error message
response.
Name
Wake-up-from-sleep delay 0.0–3600.0s (valid when P01.19 is 2)
Restart after power cut
06 01 14 00 32
Parameter
Write
command
03 02
Read
2-byte
command
Detailed parameter description
0: Restart is disabled
1: Restart is enabled
Parameter
address data
00 32
Parameter
data
data
-259-
Chapter 9
Default
v alue
0.0s
0
49 E7
CRC
39 91
CRC