Galil DMC-4040, Руководство пользователя

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Step 8c. Connect Step Motors
In Stepper Motor operation, the pulse output signal has a 50% duty cycle. Step motors operate open loop and do not
require encoder feedback. When a stepper is used, the auxiliary encoder for the corresponding axis is unavailable
for an external connection. If an encoder is used for position feedback, connect the encoder to the main encoder
input corresponding to that axis. The commanded position of the stepper can be interrogated with RP or TD. The
encoder position can be interrogated with TP.
If encoders are available on the stepper motor, Galil’s Stepper Position Maintenance Mode may be used for
automatic monitoring and correction of the stepper position. See Stepper Position Maintenance Mode (SPM) in
Chapter 6 Programming Motion for more information.
The frequency of the step motor pulses can be smoothed with the filter parameter, KS. The KS parameter has a
range between 0.25 and 64, where 64 implies the largest amount of smoothing.
See Command Reference regarding
KS .
The DMC-40x0 profiler commands the step motor amplifier. All DMC-40x0 motion commands apply such as PR,
PA, VP, CR and JG. The acceleration, deceleration, slew speed and smoothing are also used. Since step motors run
open-loop, the PID filter does not function and the position error is not generated.
To connect step motors with the DMC-40x0 you must follow this procedure – If you have a Galil integrated stepper
driver skip Step A, the step and direction lines are already connected to the driver:
Step A. Connect step and direction signals from controller to motor amplifier
From the controller to respective signals on your step motor amplifier. (These signals are labeled STPA
and DIRA for the A-axis on the EXTERNAL DRIVER (A-D) D-Sub connector top of the controller).
Consult the documentation for connecting these signals to your step motor amplifier.
Step B. Configure DMC-40x0 for motor type using MT command. You can configure the DMC-40x0 for
active high or active low pulses. Use the command MT 2 or 2.5 for active low step motor pulses and MT -
2 or -2.5 for active high step motor pulses.
See description of the MT command in the Command
Reference.
Step 9. Tune the Servo System
Adjusting the tuning parameters is required when using servo motors (standard or sinusoidal commutation). The
system compensation provides fast and accurate response and the following section suggests a simple and easy way
for compensation. More advanced design methods are available with software design tools from Galil, such as the
GalilTools.
The filter has three parameters: the damping, KD; the proportional gain, KP; and the integrator, KI. The parameters
should be selected in this order.
To start, set the integrator to zero with the instruction
KI 0 <return>
Integrator gain
and set the proportional gain to a low value, such as
KP 1 <return>
Proportional gain
KD 100 <return>
Derivative gain
For more damping, you can increase KD (maximum is 4095.875). Increase gradually and stop after the motor
vibrates. A vibration is noticed by audible sound or by interrogation. If you send the command
TE A <return>
Tell error
a few times, and get varying responses, especially with reversing polarity, it indicates system vibration. When this
happens, simply reduce KD by about 20%.
DMC-40x0 User Manual Chapter 2 Getting Started
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