Positioning accuracy is bad – Panasonic MDDDT5540 User Manual

Page 71

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Important

information

Positioning accuracy is bad.

C a t e g o r y

S y s t e m

A d j u s t m e n t

Parameter

Wiring

Installation

C a u s e s

Position commands (amount of

c o m m a n d p u l s e s ) a r e n o t c o r -

r e c t .

R e a d i n g o f i n - p o s i t i o n s i g n a l s

occurs at the edge.

The form and width of the com-

m a n d p u l s e s d e v i a t e f r o m t h e

specified values.

T h e p o s i t i o n l o o p g a i n i s t o o

small.

The setting of in-position detec-

tion range (Pr60) is too large.

The command pulse frequency

exceeds 500 kpps.

CN I/F signals are chattering:

1) Servo-ON signals

2) Counter clear input

Load inertia is large.

C o u n t e r m e a s u r e s

Count the number of feedback pulses on the monitor

screen of PANATERM

while repeating travel to back

and forth within a fixed distance. If the number of

feedback pulses varies, adjust the controller. Take

measures to reduce the noise on the command pulse.

Use the waveform graphic screen of PANATERM

to monitor the position error when the in-position

signals are received. Read the in-position signals at

a mid point on the time span, not at the edge.

If the command pulses are deformed or narrowed,

adjust the pulse generation circuit. Take measures

to reduce the noise on the command pulse.

Check the amount of position error on the monitor

screen of PANATERM

. Increase the value of Pr10

to the extent that no oscillation occurs.

Decrease the value of Pr60 (in-position range) to the

extent that the in-position signals do not chatter.

Decrease the command pulse frequency. Change the

values of Pr46 through Pr47 (numerator of 1st to

2nd command scale).

1) Check the wiring and connections between CN I/F pins 2

and 13 by monitoring the display of input and output sig-

nals status. Modify the wiring so that Servo-ON signals

can be made active correctly. Check the controller.

2) Check the wiring and connections between CN I/F pins 4

and 13 by monitoring the display of input and output sig-

nals status. Modify the wiring so that the position error

counter clear input cannot be made active during op-

eration. Check the controller.

Check the overshoot at stop using the wave form graphics

function of PANATERM

. Adjust the gains. If this is not ef-

fective, increase the capacity of the amplifier and motor.

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