Mitsubishi Electric FR-F820-00046 Instruction Manual page 491

*3 Data check time
Monitoring, operation command, frequency setting (RAM) Less than 12 ms
Parameter read/write, frequency setting (EEPROM)
Parameter clear / All parameter clear
Reset command
 Retry count setting (Pr.121, Pr.335)
• Set the permissible number of retries at data receive error occurrence. (Refer to
• When the data receive errors occur consecutively and the number of retries exceeds the permissible number setting, a
communication fault (PU connector communication: E.PUE, RS-485 terminal communication: E.SER) occurs and the
inverter output is shut off.
• When a data transmission error occurs while "9999" is set, the inverter does not shut off its output but outputs the Alarm
(LF) signal. 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 an output terminal.
Computer
Inverter
Computer
Inverter
NOTE
• For the RS-485 terminal communication, the operation at a communication error occurrence depends on the Pr.502 Stop
mode selection at communication error setting. (Refer to
 Signal loss detection (Pr.122, Pr.336 RS-485 communication check time
interval)
• If a signal loss (communication stop) is detected between the inverter and computer as a result of a signal loss detection,
a communication error (PU connector communication: E.PUE, RS-485 terminal communication: E.SER) occurs and the
inverter output is shut off.
• The LF signal is not output when a signal loss is detected. However, when a signal loss is detected via communication
through the RS-485 terminals while Pr.502 = "3 or 4", the LF signal is output.
• When the setting is "9999", communication check (signal loss detection) is not made.
• When the setting is "0", communication through the PU connector is not possible. The monitor items and parameter
settings can be read during communication via RS-485 terminals, but a communication error (E.SER) occurs instantly
when the operation mode is switched to the Network operation.
• A signal loss detection is made when the setting is any of "0.1 s to 999.8 s". To make a signal loss detection, it is necessary
to send data (for details on control codes, refer to
interval. (The inverter makes a communication check (clearing of communication check counter) regardless of the station
number setting of the data sent from the master).
490
5. PARAMETERS
5.12 (N) Communication operation parameters
Item
Example: PU connector communication, Pr. 121 = "1" (initial value)
Inverter
Computer
ALM
Example: PU connector communication, Pr. 121 = "9999"
Inverter
Computer
LF OFF
ALM
Check time
Less than 30 ms
Less than 5 s
No reply
Illegal Illegal
Reception error
Illegal Illegal
Reception error
ON
OFF
page 478.)
page 487) from the computer within the communication check time
page 489 for data receive error for retry.)
Fault (E.PUE)
Reception error
ON
Normal
Reception error
ON