Troubleshooting In Position Control - Mitsubishi Electric FR-A820-00046 Instruction Manual

Fr-a800 series
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Parameters
5.5.10

Troubleshooting in position control

Condition
The motor does not
1
rotate.
The position is
2
unfavorably shifted.
Hunting occurs in the
3
motor or the machine.
Machine movement is
4
unstable.
Tab. 5-71:
FR-A800
Position control under vector control and PM sensorless vector control
Cause
There is incorrect phase
sequence between the motor
wiring and encoder wiring.
Control mode selection setting
Pr. 800 "Control method
selection" is not appropriate.
No servo ON or stroke end signals
(STF/STR) are input.
A command pulse or position
pulse sign (NP) is not correctly
input.
The setting in Pr. 419 "Position
command source selection"
(position command source
selection) is not correct.
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.
The option to be used and
parameter settings do not match.
A command pulse is not correctly
input.
The command is affected by
noise. Noise is superpositioned
on the encoder feedback signals.
Position loop gain is too high.
Speed loop gain is too high.
Acceleration/deceleration time
settings are affecting adversely.
Troubleshooting
Vector
Vector
Vector
PM
PM
PM
Countermeasure
Check the wiring. (Refer to page 2-77.)
Check the Pr. 800 setting. (Refer to page 5-61.)
Check if a signal is properly 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)
Check the position command source selection in
Pr. 419.
Check the position feed length in Pr. 465 to Pr. 494.
Correctly set Pr. 862 "Encoder option selection"
according to the option to be used.
(Refer to page 5-69)
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)
Set Pr. 72 "PWM frequency selection" lower.
Change the earthing (grounding) position of the
shielded cable. Alternatively, do not connect it.
Set Pr. 422 "Position control gain" lower.
Perform easy gain tuning.
Set Pr. 820 "Speed control P gain 1" lower and
Pr. 821 "Speed control integral time 1" higher.
Set Pr. 7 "Acceleration time" and Pr. 8 "Deceleration
time" lower.
5 - 191

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