D-serie LEVEL II - 第111页
Axis Dynamics Axis Dynamic Basics S tude nt 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 diffe r…
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.
See also:
J 7.1 Axis Dynamic Basics [J7-1]
NOTE:
In the case of mechanical or electrical faults, the quality of the A364 axis controller is such that
the error state from longer positioning times or signal changes will only be visible if the deviation
is very significant.
Axis Dynamics
Position Measuring System Track Signals and Zero Pulse Signal
Student Guide Advanced Level 2 SIPLACE D Series
Axis Dynamics EN 05/2007
7-6
7.2 Position Measuring System
7.2.1 Track Signals and Zero Pulse Signal
Our Axes systems consists of the following parts.
Axis controller for main board
Servo amplifier
Motor
Position measuring system with incremental scale and encoder
7-4: Principle circuit for position measuring systems
Legend
The axis control system with closed position control loop determines the axis position directly, based
on the mechanical movement of the axis. The position measurement system generates analog track and
zero pulse signals during movement over the incremental scale. An amplifier, a multiplier switch and a
signal former are integrated into the encoder housing. A test connector for digital signals is either
installed on the next interface board or the digital signals are measured at track A/B and the zero pulse
output of the SIPLACE axis tester. The track signals are the only feedback loops in all the axis control
systems of the SIPLACE machine. This means that each track recognition error affects the axis control
system. The gantry axes immediately stop at a fault; the head axes finish the positioning to target before
showing a track signal error.
1 Incremental scale with zero pulses 4 Electronic signal multiplication and signal
digitalization
2 Incremental encoder for track A/B and zero
pulse signals (O pulse.)
5 Test output digital signals
3 Analog signal output and amplifier 6 Axis controller
NOTE:
The incremental encoders in 1 field lens technology have the same general construction. The
transmitter and receiver of A/B count signals are located behind a common lens window.
NOTE:
This new incremental encoder supplies track signal output amplitudes of between 1.8 and
3.6 Vss, compared to the old incremental encoder which achieved a maximum value of 2.5 Vss.