Omron SYSDRIVE MX SERIES User Manual page 157

Setting
ModBus communication requires the following settings. Be sure to set the parameters as shown
below.
If the parameter settings are changed, the new settings are enabled at the point of change.
However, ModBus communication will not start until "485" is selected with the 485/OPE selector
and the Inverter is turned on again.
The parameters of C070s cannot be changed or set through ModBus communication. Set using the
attached Digital Operator.
Parameter No. Function name
A001 Frequency reference selection
A002 RUN command selection
C071 Communication speed selection
C072 Communication station No. selection 1 to 32
C074 Communication parity selection
C075 Communication stop bit selection
C078 Communication wait time
Communication Procedure
•Follow the procedures below in regard to communication between the external control device and
the Inverter.
External controller
Inverter
1: Frame to be sent from the external control device to the Inverter (Query)
2: Frame to be returned from the Inverter to the external control device (Response)
The Inverter returns a response (Frame (2)) only after receiving a query (Frame (1)) and does not
output a response positively.
Below is each frame format (command).
Message Configuration: Query
Header (Silent interval)
Slave address
Function code
Trailer (Silent interval)
00 (VR), 01 (Terminal), 02 (Digital Operator), 03 (Modbus
communication)
01 (Terminal), 02 (Digital Operator), 03 (Modbus
communication)
04 (4800 bps), 05 (9600 bps), 06 (19200 bps)
00 (No parity), 01 (Even parity), 02 (Odd parity)
1 (1 bit), 2 (2 bits)
0 to 1000 ms
1
Wait time (silent interval +C078)
Data
Error check
4-2 Function Mode
Description
Time
2
4
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