Galil Motion Control DMC-42 0 Series, Руководство пользователя

Страница: 94 / 218

This can be performed by commanding the X and N axes to perform circular motion. Note that the value of VS
must be
VS=2π * R * F
where R is the radius, or amplitude and F is the frequency in Hz.
Set VA and VD to maximum values for the fastest acceleration.
INSTRUCTION INTERPRETATION
VMXN Select Axes
VA 68000000 Maximum Acceleration
VD 68000000 Maximum Deceleration
VS 125664 VS for 20 Hz
CR 1000, -90, 3600 Ten Cycles
VE
BGS
Stepper Motor Operation
When configured for stepper motor operation, several commands are interpreted differently than from servo
mode. The following describes operation with stepper motors.
Specifying Stepper Motor Operation
Stepper motor operation is specified by the command MT. The argument for MT is as follows:
2 specifies a stepper motor with active low step output pulses
-2 specifies a stepper motor with active high step output pulses
2.5 specifies a stepper motor with active low step output pulses and reversed direction
-2.5 specifies a stepper motor with active high step output pulse and reversed direction
Stepper Motor Smoothing
The command, KS, provides stepper motor smoothing. The effect of the smoothing can be thought of as a simple
Resistor-Capacitor (single pole) filter. The filter occurs after the motion profiler and has the effect of smoothing out
the spacing of pulses for a more smooth operation of the stepper motor. Use of KS is most applicable when
operating in full step or half step operation. KS will cause the step pulses to be delayed in accordance with the time
constant specified.
When operating with stepper motors, you will always have some amount of stepper motor smoothing, KS. Since
this filtering effect occurs after the profiler, the profiler may be ready for additional moves before all of the step
pulses have gone through the filter. It is important to consider this effect since steps may be lost if the controller is
commanded to generate an additional move before the previous move has been completed. See the discussion
below, Monitoring Generated Pulses vs. Commanded Pulses.
The general motion smoothing command, IT, can also be used. The purpose of the command, IT, is to smooth out
the motion profile and decrease ‘jerk’ due to acceleration.
Monitoring Generated Pulses vs. Commanded Pulses
For proper controller operation, it is necessary to make sure that the controller has completed generating all step
pulses before making additional moves. This is most particularly important if you are moving back and forth. For
example, when operating with servo motors, the trippoint AM (After Motion) is used to determine when the
motion profiler is complete and is prepared to execute a new motion command. However when operating in
stepper mode, the controller may still be generating step pulses when the motion profiler is complete. This is
caused by the stepper motor smoothing filter, KS. To understand this, consider the steps the controller executes to
generate step pulses:
Chapter 6 Programming Motion ▫ 90 DMC-42x0 User Manual