Precautions for Correct Use
•
The Modbus mapping function settings are reflected on not only Modbus communication, but
also USB communications and communications units.
Set and use the USB communications and communications units as follows.
When using CX-Drive: When the CX-Drive is used to read/write parameters, be sure to
set in advance the Modbus Mapping Function Selection (P200) to
00 (Standard Modbus address).
If the Modbus Mapping Function Selection (P200) is set to 01
(Modbus mapping enabled), the operation is performed for the set
address. Therefore the data is not read/written from/to the
intended parameter.
When using communi-
cations units:
The internal processing between the inverter and communications
unit cannot be performed normally. Be sure to set the Modbus
Mapping Function Selection (P200) to 00 (Standard Modbus
address).
•
If the same address is set in the Modbus Mapping External Register 1 to 10 (P201 to P210),
the inverter will return an exception response with the exception code “32 hex” attached to
the communications command.
•
If an address that does not exist in the internal Modbus register or double-word data address
is set in the Modbus Mapping Internal Register 1 to 10 (P301 to P310), the inverter will return
an exception response with the exception code “31 hex” or “32 hex” attached to the commu-
nications command.
•
Be sure to set the Modbus Mapping External Register Type 1 to 10 (P211 to P220) and Mod-
bus Mapping Scaling 1 to 10 (P221 to P230) correctly. After setting these parameters, check
that data values are set as intended.
Note that the inverter does not perform checks other than the upper and lower limit checks
and operates according to settings even if they are incorrect.
8-7-3 Compressed Single-word Registers
The Modbus mapping function is intended for 16-bit single-word data only and does not support dou-
ble-word data and coils. Therefore, the main information with double-word data is compressed into sin-
gle-word data to be used in the Modbus mapping function. Also, the main coils with single-word data
are provided.
For compressed single-word registers, refer to the list below.
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