Mitsubishi Electric FR-A700 EC, Instruction Manual

Page: 322 / 826

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