An attempt was made to return to the reference position without satisfying
the condition that, when the tool is moving toward the reference position
with a positional deviation (DGN. 300) of 128 or more pulses, at least a
one–turn signal is received.
Moreover, for the α absolute pulse coder, a reference position return was
attempted without first turning the power off then on again after rotating
the motor one turn when the system is started, or when the battery is
replaced in response to a battery zero alarm.