
7. TROUBLESHOOTING
B–63325EN/03
382
(1)
YES
NO
NO
YES
Check whether the motor rotates through at least one turn
(that is, check that the one–rotation signal is received) when
the positional deviation is 128 pulses or more.
Does motor
rotate through
one turn?
The return start position is too close.
S Change the return start position (to a
more distant position).
S Cause a rapid traverse in the reference
position return direction by rotating the
motor through at least one turn with 128
or more pulses of positional deviation.
Check that the pulse coder voltage is 4.75 V or higher.
Remove the cover of the servo motor, and measure the pulse coder
voltage across the + and – electrodes or across the +5–V and 0–V
check lands on the pulse coder printed circuit board.
4.75 V or higher?
Hardware is defective.
S The pulse coder is defective. ³ Replace
the pulse coder or motor.
The supply voltage for the pulse
coder is too low.
CAUTION
(1)After the pulse coder or motor has been replaced, the
reference positions and machine reference positions will
differ from those used before the replacement. Therefore,
adjustment and setting are required.
Tip:
A feedrate for at least 128 pulses of positional deviation is
required because, if a lower feedrate is used, the
one–rotation signal of the motor may fluctuate, disabling
correct position detection.
In parameter No. 1841, a value of less than 128 can be set
as the positional deviation with which reference position
return is assumed to be possible. (If the setting is 0, 128 is
assumed.)