Mitsubishi Electric FR-F740 EC Instruction Manual page 413

Parameter
Invalid during the BACnet MS/TP protocol.
For the Modbus-RTU protocol, the data length is fixed to 8 bits and the stop bit depends on
the Pr. 334 setting. (Refer to section 6.18.7.) For the BACnet MS/TP protocol, the data length
is always 8 bits and the stop bit is always 8 bit.
The Modbus-RTU protocol becomes invalid.
The Modbus-RTU protocol and BACnet MS/TP protocol are valid for only communication
from the RS485 terminals.
The inverter works with the initial value if a value other than the setting range is set.
NOTES If communication is made without Pr. 336 "RS485 communication check time interval" being
changed from "0" (initial value), monitor, parameter read, etc. can be performed, but the
inverter results in an alarm as soon as it is switched to the NET operation mode. If the oper-
ation mode at power on is the network operation mode, a communication alarm (E.SER)
occurs after first communication.
When performing operation or parameter write through communication, set "9999" or more
to Pr. 336. (The setting depends on the computer side program.) (Refer to page 6-277.)
Always reset the inverter after making the initial settings of the parameters. After you have
changed the communication-related parameters, communication cannot be made until the
inverter is reset.
FR-F700 EC
Communication operation and setting
6 - 263