Communication Eeprom Write Selection (Pr. 342) - Mitsubishi Electric FR-A760 Series Instruction Manual

Communication operation and setting
[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 331)
*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 a fault 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 fault (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 323)
⋅ 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
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
"1" (only RAM write)
is set to
Therefore, the parameter values available when power is switched on again are the values stored in EEPROM previously.
318
Initial
Name
Value
96
0s
9999
Name
Initial Value
, the new values of the parameters will be cleared at power supply-off of the inverter.
Setting Range
0 to 31 (0 to 247)
0
*1
3, 6, 12, 24, 48,
96, 192, 384
1 0, 1, 10, 11
2 0, 1, 2
1 0 to 10, 9999
0
0.1 to 999.8s
9999
0 to 150ms,
9999
1 0, 1, 2
0
1
1
Setting
Range
0
0
1
Description
Set the inverter station number. (same
specifications as Pr. 117)
Used to select the communication speed.
(same specifications as Pr. 118)
Select stop bit length and data length. (same
specifications as Pr. 119)
Select the parity check specifications. (same
specifications as Pr. 120)
Set the permissible number of retries at
occurrence of a data receive error.
(same specifications as Pr. 121)
RS-485 communication can be made, but the
inverter will come to trip in the NET operation
mode.
Set the interval of communication check time.
(same specifications as Pr. 122)
No communication check
detection)
Set the waiting time
transmission to the inverter and response.
(same specifications as Pr. 123)
Select presence/absence of CR/LF.
(same specifications as Pr. 124)
Mitsubishi inverter (computer link) protocol
Modbus-RTU protocol
*4
Description
Parameter values written by communication are
written to the EEPROM and RAM.
Parameter values written by communication
are written to the RAM.
(Refer to page 296)
(signal loss
between data