D-serie LEVEL II.pdf - 第110页

Axis Dynamics Axis Dynamic Basics S tuden t Guide Advanced Level 2 SIPLACE D Series Axis Dynamics EN 05/2007 7-4 7-2: The uncommutated motor current nomin al signal (3) and the motor cur rent signals (1) (2) of an AC Mot…

Axis Dynamics

Axis Dynamic Basics

Student Guide Advanced Level 2 SIPLACE D Series

EN 05/2007 Axis Dynamics

7-3

The overswing explained above shows that the waiting time for the overswing check starts at 13 digits

before the target area and that the end position signal is set at 5 ms after this.

The movements of approx. 6 µm which then occur can then be ignored. These do not affect the machine

or the placement process.

For assessment of the axis dynamics by a service technician, the system generates an uncommutated

current nominal signal from all motor current nominal signals. This informs you about the mechanical

friction in the axis system. It can be measured on the adapter board of the axis controller 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 nominal

signals from the axis controller. The missing 3rd motor current signal is calculated at the Servo board.

The known V nominal (V-target) speed signal and the force signal have been replaced by the motor

current nominal signals for DC or AC drives.

NOTE:

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

axis tester. The same signals are measured at the two topmost test points of the servo amplifier

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

Axis Dynamics

Axis Dynamic Basics

Student Guide Advanced Level 2 SIPLACE D Series

Axis Dynamics EN 05/2007

7-4

7-2: 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 becomes higher as the speed increases, up to a maximum frequency for maximum axis

speed (2).

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

The frequency is reduced to a lower value, thereby also reducing the speed of the axis (3). 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 be

overcome. The higher the friction is, the higher the amplitudes will be at acceleration and constant

speed. The higher motor force at acceleration and constant speed can be detected at the uncommutated

motor current nominal signal. Higher friction reduces the required motor force during the deceleration

section, so that the amplitude is smaller for the uncommutated motor current nominal signal.

Axis Dynamics

Axis Dynamic Basics

Student Guide Advanced Level 2 SIPLACE D Series

EN 05/2007 Axis Dynamics

7-5

7-3: Axis block diagram example X or Y-axis of HF/Siplace X machine

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

control signals for 2 or 3 phase axis drive are transmitted to the servo. For DC drives, we use the same

hardware principle, with only one 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.