Mitsubishi FREQROL-SF Troubleshooting Manual page 34

Item Cause
The printed circuit
board in the motor
built-in encoder
(motor terminal box) is
defective.
7
The sensor in the motor
built-in encoder is
defective.
a
Check
the check pins on the printed
circuit board SF-CA card
using an oscilloscope.
Phase A signal: CH44-CH9
(or AGA)
Phase B signal: CH45-CH9
(or AGA)
(See Appendixes 6(l) and
(Note) Before using the check
pins, the power of the
amplifier should have been
turned off.
at several ten rpm and the
speed display indicates "0".
Item 6 above, in the open
loop state, rotate the motor
at a low speed.
Item 6, check the signal
waveform of the check pins on
the SF-CA card using an
oscilloscope.
tion relating to adjustment
and replacement of the motor
built-in encoder described
in Section 2.9, observe the
waveforms between PA and PGA
and between PB and PGA using
an oscilloscope and check
that they can be in the
standard value range using
volume resistors (VRl, VR2,
VR3 and VR4).
forms between PA and PGA and
between PB and PGA on the
encoder printed circuit board o If the motor cannot be
cannot be adjusted in the
standard value range even
after the printed circuit
board has been replaced in
the manner described in the
Item 7 above.
1 Troubleshooting
1.3
Checking method and
remedy of trouble
Remedy
board in the motor terminal
box and adjust the controls
by referencing Section 2.9.
with a new one.
replaced, replace it
together with the sensor
and printed circuit board
by referencing Section
2.9.