Mitsubishi Electric FR-A700 Series, Technical Manual

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318
PARAMETER
2.11.8 Troubleshooting (position control)
(A700)
Case 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 86)
(2) [
Pr. 800 The control mode selection
]
setting is improper.
(2) Check the [
Pr. 800
] setting. (Refer to page 252)
(3) The servo ON signal or stroke end
signal (STF, STR) is not input.
(3) Check that the signals are input correctly.
(4) Command pulse, position pulse
sign (NP) are not correctly input.
(4)-1 Check that the command pulses are input correctly.
(Check the cumulative command pulse value in [
Pr. 430
])
(4)-2 Check the command pulse form and [
Pr. 428 Command
pulse selection
] setting.
(4)-3 Check that the position pulse sign (NP) is assigned to
the input terminal. (inverter pulse input)
(5) The [
Pr. 419 Position command
source selection
] setting is not
correct.
(5) Check the [
Pr. 419 Position command source selection
].
(6) When the [
Pr. 419 Position
command source selection
] setting
is 0, the position feed amount [
Pr.
465 to Pr. 494
] settings 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 [
Pr. 428 Command
pulse selection
] setting.
(1)-2 Check that the command pulses are input correctly.
(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 feedback signal is
compounded with noise.
(2)-1 Decrease [
Pr. 72 PWM frequency selection
].
(2)-2 Change the earthing (grounding) point of shielded wire.
Or leave the cable suspended.
3 Motor or machine hunts.
(1) The position loop gain is high. (1) Decrease [
Pr. 422
].
(2) The speed loop 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 the [
Pr. 7, Pr. 8
] value.
A700