Mitsubishi Electric FR-A700 Instruction Manual page 322

Position control by vector control
Troubleshooting
Phenomenon
1 Motor does not rotate.
2 Position shift occurs.
3 Motor or machine hunts.
Machine operation is
4
unstable.
Tab. 6-27: Troubleshooting
6 - 142
Cause
(1) The phase sequence of the
motor or encoder wiring is
wrong.
(2) The control mode selection
Pr. 800 setting is improper.
(3) The servo on signal or stroke
end signal (STF, STR) is not
input.
(4) Command pulse, position
pulse sign (NP) are not cor-
rectly input.
(5) Pr. 419 "Position command
source" selection setting is not
correct.
(6) When "0" is set in Pr. 419
"Position command source
selection", the settings of posi-
tion feed amount in Pr. 465 to
Pr. 494 are not correct.
(1) The command pulses are not
input correctly.
(2) The command is affected by
noise. Or the encoder feed-
back signal is compounded
with noise.
(1) The position loop gain is high.
(2) The speed gain is high.
(1) The acceleration/deceleration
time setting has adverse effect.
Countermeasures
(1) Check the wiring. (Refer to page 3-38.)
(2) Check the Pr. 800 setting.
(Refer to section 6.2.2.)
(3) Check that the signals are input normally.
(4)-1 Check that the command pulses are
input normally. (Check the cumulative
command pulse value in Pr. 430.)
(4)-2 Check the command pulse form and
command pulse selection, Pr. 428, set-
ting.
(4)-3 Check that the position pulse sign (NP)
is assigned to the input terminal.
(inverter pulse input)
(5) Check the position command source selec-
tion in Pr. 419.
(6) Check the position feed amount in Pr. 465
to Pr. 494.
(1)-1 Check the command pulse form and
command pulse selection, Pr. 428 set-
ting.
(1)-2 Check that the command pulses are
input normally. (Check the cumulative
command pulse value in Pr. 430 )
(1)-3 Check that the position pulse sign (NP)
is assigned to the input terminal.
(inverter pulse input)
(2)-1 Decrease the Pr. 72 "PWM frequency
selection" value.
(2)-2 Change the earthing (grounding) point
of shielded wire. Or leave the cable sus-
pended.
(1) Decrease the Pr. 422 value.
(2)-1 Perform easy gain tuning.
(2)-2 Decrease Pr. 820 and increase Pr. 821.
(1) Decrease Pr. 7 and Pr. 8.
Parameter