Mitsubishi Electric 800 Series Instruction Manual page 480

 Setting the communication protocol (Pr.549)
• Select the communication protocol.
• The MODBUS RTU protocol can be used by communication from the RS-485 terminals.
Pr.549 setting
0 (initial value) Mitsubishi inverter protocol (computer link)
1 MODBUS RTU protocol
2 BACnet MS/TP protocol
 Communication EEPROM write selection (Pr.342)
• When parameter write is performed via the inverter PU connector, RS-485 terminal, USB communication, or a
communication option, the parameters storage device can be changed from EEPROM + RAM to RAM only. Use this
function if parameter settings are changed frequently.
• When changing the parameter values frequently, set "1" in Pr.342 Communication EEPROM write selection to write
them to the RAM only. The life of the EEPROM will be shorter if parameter write is performed frequently with the setting
unchanged from "0 (initial value)" (EEPROM write).
NOTE
• Turning OFF the inverter's power supply clears the modified parameter settings when Pr.342 = "1 (write only to RAM)".
Therefore, the parameter values at next power-ON are the values last stored in EEPROM.
• The parameter setting written in RAM cannot be checked on the operation panel. (The values displayed on the operation
panel are the ones stored in EEPROM.)
 Operation selection at a communication error (Pr.502, Pr.779)
• For communication using RS-485 terminals or a communication option, operation at a communication error can be
selected. The operation is active under the Network operation mode.
• Select the stop operation at the retry count excess (Pr.335, only with Mitsubishi inverter protocol) or at a signal loss
detection (Pr.336, Pr.539).
Fault record Pr.502
setting
Communication 0
line (initial value)
1
2
3
4
Communication 0, 3
option (when a
1, 2
communication
option is used)
4
*1 If in communication by the communication option, E.OP1 is displayed.
*2 When the communication error is removed during deceleration, the motor re-accelerates.
• When a communication error is detected during communication through the RS-485 terminals or communication option,
the alarm (LF) signal is output to an output terminal of the inverter. To use the LF signal, set "98 (positive logic) or 198
(negative logic)" in any of Pr.190 to Pr.196 (Output terminal function selection) to assign the function to the output
terminal. (To output the LF signal even if communication through RS-485 terminals is not performed for the time set in
Pr.336 or longer, or during communication using a communication option, set "3 or 4" in Pr.502.)
Communication protocol
At fault occurrence
Operation Indication
Output shutoff
*1
"E.SER"
Output to "E.SER" after
decelerate and
*1
stop
stop the motor
Operation Normal
continues at the
"CF" warning
set frequency of
Pr.779.
Output shutoff "E.1"
Output to "E.1" after
decelerate and stop
stop the motor
Operation "CF" warning
continues at the
set frequency of
Pr.779.
Fault (ALM) Operation
signal
ON Output stop
status continues.
ON after stop
OFF
*2
Restart
OFF Normal
OFF
ON Output stop
status continues.
ON after stop
OFF Operation
continues at the
set frequency of
Pr.779.
5.12 (N) Operation via communication and its settings
At fault removal
Indication Fault (ALM)
signal
ON
*1
"E.SER"
Normal OFF
Normal OFF
"E.1" ON
"CF" warning OFF
5. PARAMETERS
3
4
5
5
5
6
7
8
9
10
479