00194614-08 Trainingsdoku. SG X-Serie_X4i SW70x (AL2)_EN.pdf - 第119页

Communication and Control Axis Control Axis Dynamic Basics 119 Student Guide SIPLACE X-Serie and X4I SW70x (AL2) The positioning shown above demons trates an excessive overshoot . However, no othe r overshoot, for which …

Communication and Control

Axis Dynamic Basics Axis Control

Student Guide SIPLACE X-Serie and X4I SW70x (AL2) 118

During initial Positioning into the target position, the actual equals target position signal triggers an

overshoot count in the axis test box (SAT) for the position deviation signal.

If the overshoot is greater than the permitted position deviation for this axis, the end position signal will

be delayed until the deviation has been regulated so that it is within the permitted range.

The 2nd overshoot sets the end signal

Positioning with asymptotic approach after the initial, excessive overshoot

NOTICE

The position deviation signal shows the positioning quality of an axis movement in position.

Communication and Control

Axis Control Axis Dynamic Basics

119 Student Guide SIPLACE X-Serie and X4I SW70x (AL2)

The positioning shown above demonstrates an excessive overshoot. However, no other overshoot, for

which an end signal could be issued, will occur during this positioning run. The axis controller has a

’backup strategy’ - When the permitted position deviation range is reached, a 10ms timer is started. 10

ms after entering the permissible range (here 5 digits (1)) the timer triggers the end position signal (2).

The permitted range must not be left during this period.

The system generates an uncommutated current target signal from all motor current target signals for

assessment of the axis dynamics by a service technician. This signal gives information about the

mechanical friction in the axis system. This can be measured on the adapter board of the axis test box

or at the Vreg output of the SIPLACE axis tester (SAT).

The uncommutated target current signal is an envelope signal for the 2 visible motor current target

signals from the axis controller. The 3rd motor current target signal (not visible) is calculated on the servo

amplifier board.

The known V nominal (Vnom) speed signal and the force signal have been replaced by the motor current

nominal signals for DC or AC drives.

The uncommutated motor current nominal signal (3) and the motor current signals (1) (2) of an AC motor

The acceleration section can be recognized in the motor current nominal signal of the AC motor (4) due

to the high amplitudes needed to supply the axis mechanics with sufficient force. The frequency of this

signal section is low, due to the low speed. The amplitude becomes lower and lower because the

necessary motor force is reduced with increasing speed.

The frequency increases as the speed of the motor rises, up to the maximum frequency for maximum

axis speed (5).

NOTICE

These motor current signals can be measured at the V nominal and the Force output of the axis

tester. The same signals are measurable at the 2 uppermost test pins on the servo amplifier

board, as Inom. U’ and Inom. W signals.

Communication and Control

Axis Dynamic Basics Axis Control

Student Guide SIPLACE X-Serie and X4I SW70x (AL2) 120

In the deceleration section, the amplitude increases again, to reduce the speed of the axis mechanics.

The frequency decreases, as does the speed of the axis (6). Finally, the axis is moved into the correct

target position, with overshoot control.

So there is nothing to adjust all this axes have a dynamic behavior. Each axis has friction to master. The

greater the friction is, the higher the amplitudes will be for acceleration and constant speed. The higher

motor force for acceleration and constant speed can be seen by the uncommutated motor current target

signal. Greater friction reduces the motor force required during the deceleration phase, making the

amplitude of the uncommutated motor current target signal smaller.

Axis block diagram, showing X or Y axis of SIPLACE X machine as example

Although the various axis types differ in details, all control tasks are handled by the axis controller. 2

control signals for 2 or 3 phase axis drive. For DC-drives we use the same hardware principle with only

1 control signal to the Servo amplifier. The only feedback is provided by the track signals from the

incremental encoder to the axis controller - a tacho (Z/DP axis) is not connected to the axis system.