IMO SD1 Series - 7.6 Common Communication Faults

SD1 Series Inverters Communication Protocol
-141-
Continuous
writing
command
VFD
address
Parameters
address
CRC check
Data
number
ASCII mode:
The command sent to the inverter:
Continuous
writing
command
Parameters
address
Data
number
VFD
address
LRC
check
If the operation succeeds, the response message is as follows:
Continuous
writing
command
Parameters
address
Data
number
VFD
address
LRC
check
Note: The blank in the above command is for illustration. The blank cannot be added in the
actual application unless the upper monitor can remove the blank by themselves.
7.6 Common Communication Faults
Common communication faults include the following:
 No response is returned.
 The inverter returns an exception response.
Possible causes of no response include the following:
 The serial port is set incorrectly. For example, the converter uses the serial port COM1, but
COM2 is selected for the communication.
 The settings of the baud rates, data bits, stop bits, and check bits are inconsistent with
those set on the inverter.
 The positive pole (+) and negative pole (-) of the RS485 bus are connected in reverse.
 The RS485 wire cap on the terminal board of the inverter is not connected. This wire cap is
at the back of the terminal block.