Emerson MP105A4 Скачать руководство пользователя страница 144

Страница: 144 / 182

144

Mentor MP User Guide

www.controltechniques.com Issue: 3

This parameter enables sequencer latching. When sequencer latching is
used, a digital input must be used as a run permit or not stop input. The
digital input should write to Pr

6.39

. The run permit or not stop input must

be made active to allow the drive to run. Making the run permit or not
stop input inactive resets the latch and stops the drive.

11.22.6 Catch a spinning motor

When the drive is enabled with this parameter at zero, the post ramp
reference (Pr

2.01

(

di03, 0.38

)) starts at zero and ramps to the required

reference. When the drive is enabled with this parameter at one, the post
ramp reference is set to the motor speed.

11.22.7 Position modes

This parameter is used to set the position controller mode as shown in
the following table.

Rigid position control

In rigid position control the position error is always accumulated. This
means that, if for example, the slave shaft is slowed down due to
excessive load, the target position will eventually be recovered by
running at a higher speed when the load is removed.

Non-rigid position control

In non-rigid position control the position loop is only active when the 'At
Speed' condition is met (see Pr

3.06

in the

Mentor MP

Advanced User

Guide

). This allows slippage to occur while the speed error is high.

Velocity feed forward

The position controller can generate a velocity feed forward value from
the speed of the reference encoder. The feed-forward value is passed to
menu 1, and so ramps may be included if required. Because the position
controller only has a proportional gain, it is necessary to use velocity
feed-forward to prevent a constant position error that would be
proportional to the speed of the reference position.
If for any reason the user wishes to provide the velocity feed forward
from a source other than the reference position, the feed forward system
can be made inactive, i.e. Pr

13.10

= 2 or 4. The external feed forward

can be provided via Menu 1 from any of the frequency/speed references.
However, if the feed forward level is not correct a constant position error
will exist.

Relative jogging

If relative jogging is enabled the feedback position can be made to move
relative to the reference position at the speed defined by Pr

13.17

Orientation

If Pr

13.10

is 5 the drive orientates the motor following a stop command.

If hold zero speed is enabled (Pr

6.08

= 1) the drive remains in position

control when orientation is complete and holds the orientation position. If
hold zero speed is not enabled the drive is disabled when orientation is
complete.
If Pr

13.10

is 6 the drive orientates the motor following a stop command

and whenever the drive is enabled provided that hold zero speed is
enabled (Pr

6.08

= 1). This ensures that the spindle is always held in the

same position following the drive being enabled.
When orientating from a stop command the drive goes through the fol-
lowing sequence:
1.

The motor is decelerated or accelerated to the speed limit pro-
grammed in Pr

13.12

, using ramps if these are enabled, in the

direction the motor was previously running.

When the ramp output reaches the speed set in Pr

13.12

, ramps

are disabled and the motor continues to rotate until the position is
found to be close to the target position (i.e. within 1/32 of a revolu-
tion). At this point the speed demand is set to 0 and the position
loop is closed.

When the position is within the window defined by Pr

13.14

, the ori-

entation complete indication is given in Pr

13.15

The stop mode selected by Pr

6.01

has no effect if orientation is

enabled.

6.40

Enable sequencer latching

Bit