Mitsubishi FR-A800

Position control under vector control and PM sensorless vector control
252
PARAMETERS
5.5.9 Troubleshooting in position control
Condition Cause Countermeasure
1 The motor does not rotate.
There is incorrect phase sequence
between the motor wiring and
encoder wiring.
Check the wiring. (Refer to page 66.)
Control mode selection setting Pr.800
Control method selection is not
appropriate.
Check the Pr.800 setting. (Refer to page 164.)
No servo ON or stroke end signals
(STF/STR) are input.
Check if a signal is properly input.
A command pulse or position pulse
sign (NP) is not correctly input.
Check if the command pulse is properly input. (check the
accumulated value for command pulses in Pr.430 Pulse
monitor selection).
Check the command pulse type in Pr.428 Command pulse
selection.
Check that the position pulse sign (NP) is assigned to an input
terminal. (inverter pulse input)
The setting in Pr.419 Position
command source selection
(position command source selection)
is not correct.
Check the position command source selection in Pr.419.
When simple position control by a
point table (Pr.419= "0") is used , the
position feed length set by Pr.465 to
Pr.494 is not correct.
Check the position feed length in Pr.465 to Pr.494.
2
The position is unfavorably
shifted.
A command pulse is not correctly
input.
Check the command pulse type in Pr.428 Command pulse
selection.
Check if the command pulse is properly input. (check the
accumulated value of command pulses in Pr.430)
Check that the position pulse sign (NP) is assigned to an input
terminal. (inverter pulse input)
The command is affected by noise.
Noise is superpositioned on the
encoder feedback signals.
Set Pr.72 PWM frequency selection lower.
Change the earthing (grounding) position of the shielded
cable. Alternatively, do not connect it.
3
Hunting occurs in the motor
or the machine.
Position loop gain is too high. Set Pr.422 Position control gain lower.
Speed loop gain is too high.
Perform easy gain tuning.
Set Pr.820 Speed control P gain 1 lower and Pr.821 Speed
control integral time 1 higher.
4
Machine movement is
unstable.
Acceleration/deceleration time
settings are affecting adversely.
Set Pr.7 Acceleration time and Pr.8 Deceleration time
lower.
Vector
Vector
Vector
PM
PM
PM