• When a communication option is used, the protective function [E.OP1 (fault data: HA1)] is activated at error occurrences on
the communication line. The protective function [E.1 (fault data: HF1)] is activated at error occurrences in the communication
circuit inside the option.
• Fault output indicates the Fault (ALM) signal and an alarm bit output.
• When the fault output is set enabled, fault records are stored in the faults history. (A fault record is written to the faults history
at a fault output.)
• When the fault output is not enabled, fault record is overwritten to the faults history temporarily but not stored.
• After the fault is removed, the fault indication goes back to normal indication on the monitor, and the faults history goes back
to the previous status.
• When Pr.502 ≠ "0", the normal deceleration time setting (settings like Pr.8, Pr.44, and Pr.45) is applied as the deceleration
time. Normal acceleration time setting (settings like Pr.7 and Pr.44) is applied as the acceleration time for restart.
• When Pr.502 = "2, 3, or 4", the inverter operates with the start command and the speed command, which were used before
• If a communication line error occurs, then the error is removed during deceleration while Pr.502 = "2", the motor re-accelerates
from that point. (When a communication option is used, acceleration does not restart at a communication option error.)
• The Pr.502 and Pr.779 settings are valid when communication is performed via the RS-485 terminals or a communication
• These parameters are valid under the Network operation mode. When performing communication through RS-485 terminals,
set Pr.551 PU mode operation command source selection ≠ "1".
• Pr.502 is valid for the device that has the command source under the Network operation mode. If a communication option is
installed while Pr.550 = "9999 (initial setting)", a communication error in RS-485 terminals occurs and Pr.502 becomes invalid.
• If the communication error setting is disabled with Pr.335 = "9999" or Pr.539 = "9999" while Pr.502 = "3 or 4", the inverter does
not operate with the frequency set in Pr.779 when a communication error occurs.
• If a communication error occurs while continuous operation at Pr.779 is selected with Pr.502 = "3 or 4", the inverter operates
at the frequency set in Pr.779 even though the speed command source is at the external terminals.
Example) If a communication error occurs while Pr.339 = "2" and the RL signal is input through an external terminal, the
operation is continued at the frequency set in Pr.779.
• During position control, an error occurs even if "2" is set in Pr.502.
• When Pr.502 = "3" and a communication line error occurs, or Pr.502 = "4" and a communication line error or a
communication option fault occurs, the operation continues. When setting "3 or 4" in Pr.502, provide a safety stop
countermeasure other than via communication. For example, input a signal through an external terminal (RES, MRS, or
X92) or press the PU stop on the operation panel.
Waiting time setting from the communication line error occurrence to the
communication error activation (Pr.500)
• When a communication option is used, use Pr.500 Communication error execution waiting time to set the time from
when the communication line error occurs until the inverter starts the operation for the communication error.
• When a communication line error occurs and lasts longer than the time set in Pr.500, it is recognized as a communication
error. If the communication returns to normal within the time, it is not recognized as a communication error, and the
Communication line status
(Pr.502 = 3)
5.15 (N) Communication operation parameters