Communication Eeprom Write Selection (Pr. 342) - Mitsubishi Electric FR-A720-0.4K Instruction Manual

[RS-485 terminal communication related parameter]
Parameter
Number
RS-485 communication station
331
number
332 RS-485 communication speed
RS-485 communication stop bit
333
*2
length
RS-485 communication parity
334
check selection
RS-485 communication retry
335
*3
count
RS-485 communication check
336
*3
time interval
RS-485 communication waiting
337
*3
time setting
RS-485 communication CR/LF
341
*3
selection
549 Protocol selection
*1 When "1" (Modbus-RTU protocol) is set in Pr. 549, the setting range within parenthesis is applied.
*2 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 page 327)
*3 The Modbus-RTU protocol becomes invalid.
*4 The Modbus-RTU protocol is valid for only communication from the RS-485 terminals.
CAUTION
⋅ If communication is made without Pr. 336 RS-485 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 operation 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 a greater value to Pr. 336. (The setting
depends on the computer side program.) (Refer to page 320)
⋅ 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.

4.24.4 Communication EEPROM write selection (Pr. 342)

Parameters written via the inverter's PU connector, RS-485 terminals, USB communication or from the
communication option can be written to the RAM. Set this parameter when frequent parameter changes are
required.
Parameter
Name
Number
Communication EEPROM write
342
selection
can be set any time when the communication option is connected.
The above parameters
⋅ When changing the parameter values frequently, set "1" in Pr. 342 to write them to the RAM. The life of the EEPROM will
be shorter if parameter write is performed frequently with the setting unchanged from "0 (initial value)" (EEPROM write).
REMARKS
⋅ When Pr. 342
is set to "1" (only RAM write)
Therefore, the parameter values available when power is switched on again are the values stored in EEPROM previously.
Initial
Name
Value
0
96
1
2
1
0s
9999
1
0
Initial Value
0
, the new values of the parameters will be cleared at power supply-off of the inverter.
Communication operation and setting
Setting Range
Set the inverter station number. (same
0 to 31 (0 to 247)
specifications as Pr. 117)
*1
3, 6, 12, 24, 48,
Used to select the communication speed.
96, 192, 384 (same specifications as Pr. 118)
Select stop bit length and data length. (same
0, 1, 10, 11
specifications as Pr. 119)
Select the parity check specifications. (same
0, 1, 2
specifications as Pr. 120)
Set the permissible number of retries at
0 to 10, 9999 occurrence of a data receive error.
(same specifications as Pr. 121)
RS-485 communication can be made, but the
0 inverter will come to an alarm stop in the NET
operation mode.
Set the interval of communication check time.
0.1 to 999.8s
(same specifications as Pr. 122)
9999 No communication check
Set the
0 to 150ms,
transmission to the inverter and response.
9999
(same specifications as Pr. 123)
Select presence/absence of CR/LF.
0, 1, 2
(same specifications as Pr. 124)
0 Mitsubishi inverter (computer link) protocol
1 Modbus-RTU protocol
Setting
Range
Parameter values written by communication are
0
written to the EEPROM and RAM.
Parameter values written by communication
1
are written to the RAM.
(Refer to page 293)
Description
waiting time between data
*4
Description
315
Pr.341
page 314
Pr.343
page 327
4