Cause : Operation panel lock comes when operation lock is set. Operation other than stop/reset is invalid. Press Mode button for 2 s to release the lock.

1. Operation using the setting dial and keys of the operation panel can be disabled to prevent parameter changes,
   unexpected starts or frequency changes.
2. When setting dial and key operations are disabled, LOCD appears on the operation panel. If setting dial or key
   operation is attempted while dial and key operations are disabled, LOCD appears. (When a setting dial or key
   operation is not performed for 2 s, the monitor display appears.)
3. To enable the setting dial and key operation again, press Mode button for 2 s.