• The communication error count is temporarily stored in the RAM memory. The value is not stored in EEPROM, and so is
cleared to 0 when power is reset and the inverter is reset.
Alarm (LF) signal output (communication error warning)
• During a communication error, the Alarm (LF) signal is output by open collector output. Assign the terminal to be used using
any of Pr.190 to Pr.196 (Output terminal function selection).
• The LF signal can be assigned to an output terminal by setting Pr.190 to Pr.196. Changing the terminal assignment may affect
other functions. Set parameters after confirming the function of each terminal.
Signal loss detection (Pr.539 RS-485 communication check time interval)
• If a signal loss (communication) is detected between the inverter and the master as a result of a signal loss detection, the
Communication fault (inverter) (E.SER) occurs and the inverter output is shut off.
• When the setting is "9999", communication check (signal loss detection) is not made.
• When the setting is "0", reading, etc. of monitors and parameters is possible, though 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". In order to enable the signal loss detection,
data must be sent by the master at an interval equal to or less than the time set for the communication check. (The inverter
makes a communication check (clearing of communication check counter) regardless of the station number setting of the
data sent from the master).
• The communication check is made from the first communication in the Network operation mode (can be changed by Pr.551
PU mode operation command source selection).
5.15 (N) Communication operation parameters
Communication error count is increased in
synchronization with leading edge of LF signal
Turns off when normal data is received
Alarm data :
Data resulting in