Application Note #5425 - Galil

Application Note #5425
Connecting a Gemini GV Amplifier to a Galil Controller
This application note describes the procedure for properly connecting and tuning a
Compumotor (a division of Parker Automation) Gemini GV amplifier using a Galil
DMC-1800 controller and an ICM-1900 interconnect module. While this document is
specific to the DMC-1800, the approach taken can be used as a reference for any
OPTIMA series controller.
Components referred to in this document include:
• Galil DMC-1800 controller
• Galil ICM-1900 interconnect module
• Galil WSDK servo tuning software
• Compumotor Gemini GV-U6E amplifier
• Compumotor brushless servo motor – model N0342FE
• Compumotor “Motion Planner” software – version 2.9
Amplifier Hardware Connections
Hardware Setup
Set up the Compumotor Gemini GV amplifier, motor, and power supply per
manufacturer’s instructions. A Gemini breakout module (P/N: 01-017940-01) would be
necessary for access to individual terminals on the 50-pin Drive I/O connector. Install and
launch the Compumotor “Motion Planner” software, and work through the setup wizard.
Selecting the right motor part number during this setup will load the appropriate motor
parameters onto the drive. Follow the instructions on the Hardware Installation Guide
manual to complete the procedure. Connect the DMC-1800 controller to the ICM-1900
with the CABLE-100-1m cable.
Connect Amplifier Enable Circuit
As the GV amplifier has an active-low enable input, make sure that the ICM-1900
module comes with a –LAEN option. For the drive to accept a 5V AEN signal, connect
the 5V from Galil’s ICM board to VINref on the breakout module to set the input
reference voltage on the amplifier to 5V.
Galil Motion Control, Inc. • 3750 Atherton Road • Rocklin, CA 95765 USA • 800-377-6329 • Ph: 916-626-0101 • Fax: 916-626-0102 • www.galilmc.com

Connect Encoder Signal
The quadrature encoder signals are connected to the ICM-1900 from the corresponding
pins (14-19) on the Gemini breakout module. The following diagram (see Fig. 1)
describes the proper connections for an x-axis system.
Note: Encoder signal connection is optional when operating in position mode.
Connect Analog Motor Command Signal
Connect MOCMD(x) ±10v analog motor command signal to Cmd+ on the Compumotor
amplifier for operations in the torque or velocity modes. Connection to the Cmd- would
not be necessary, since our command signal is single-ended. For ground reference,
connect GND on the ICM to the Analog Ground on the Compumotor amplifier. For
connections in the position mode, go through the steps described in the Galil user manual
for connecting stepper motors (see chapter 2). Connections for position mode can be seen
in figure 2.
Compumotor
GV Amplifier
Drive I/O Motor Feedback
Analog Ground (pin 25)
+/- 10V Cmd- (no connect)
+/- 10V Cmd+ (pin 23)
Enable (pin 1)
EN. OUT A+ (pin 14)
EN. OUT A- (pin 15)
EN. OUT B+ (pin 16)
EN. OUT B- (pin 17)
EN. OUT Z+ (pin 18)
EN. OUT Z- (pin 19)
GND (pin 17)
MOCMDX (pin 32)
AMPENX (pin 40)
Galil
ICM-1900 - LAEN
VINref (pin 26) +5V (pin 36)
To N0342FE
Brushless
Servo Motor
+MAX (pin 83)
-MAX (pin 84)
+MBX (pin 85)
-MBX (pin 86)
+INX (pin 87)
-INX (pin 88)
Figure 1: Basic hardware connections for torque / velocity modes
Galil Motion Control, Inc. • 3750 Atherton Road • Rocklin, CA 95765 USA • 800-377-6329 • Ph: 916-626-0101 • Fax: 916-626-0102 • www.galilmc.com

Compumotor
GV Amplifier
Drive I/O Motor Feedback
Digital Ground (pin 6 or 7)
Dir+ (pin 10)
Step+ (pin 8)
Enable (pin 1)
EN. OUT A+ (pin 14)
EN. OUT A- (pin 15)
EN. OUT B+ (pin 16)
EN. OUT B- (pin 17)
EN. OUT Z+ (pin 18)
EN. OUT Z- (pin 19)
GND (pin 17)
PWMX (pin 34)
AMPENX (pin 40)
Galil
ICM-1900 - LAEN
VINref (pin 26) +5V (pin 36)
To N0342FE
Brushless
Servo Motor
SIGNX (pin 33)
optional
Figure 2: Basic hardware connections for position mode
Performance Notes
+MAX (pin 83)
-MAX (pin 84)
+MBX (pin 85)
-MBX (pin 86)
+INX (pin 87)
-INX (pin 88)
The following notes are written to explain the tuning procedures when the Gemini
amplifier is in the torque and velocity modes. The DMODE command sets the operational
mode in the Motion Planner software. Since the position mode is operated under an open
loop condition, no tuning of the controller is required in this mode.
Note: The planetary gear-head on the N0342FE motor was removed during this tuning
analysis in order to achieve a more conclusive characterization of the motor.
Torque Mode
When set to torque mode (DMODE2), the Gemini GV has no internal control loop, thus
tuning is only done through the Galil controller using our WSDK software. However,
advanced adjustments to the Gemini GV drive in this mode can be made; a section called
‘Torque Mode Tuning Procedure’ can be found on the Gemini’s hardware installation
guide. Best tuning results seem to come from the Auto Crossover Frequency test, but due
to the high torque-density packaging of the motor, system response may be unrepeatable.
Galil Motion Control, Inc. • 3750 Atherton Road • Rocklin, CA 95765 USA • 800-377-6329 • Ph: 916-626-0101 • Fax: 916-626-0102 • www.galilmc.com

To further improve on the step response attained during the Auto Crossover test, switch
to the Manual Tuning method and begin fine-tuning by changing the KD and KP values
to achieve a minimal overshoot and quick settling time for the step response. Then, adjust
KI for positional accuracy. Decreasing the controller’s update time (500μsec minimum)
causes the Auto Crossover test to yield higher PID values. If instability starts occurring
due to the higher control filter (seen as high frequency oscillations in the step response),
proceed to the manual tuning method and decrease the PID values until the step response
becomes more stable.
Velocity Mode
When set to velocity mode (DMODE4), the Gemini amplifier has three basic tuning
parameters that can be adjusted. They are DVBW, SGVRAT and SGINTE (refer to your
Gemini command reference set). However, each motor model has its own set of default
parameters, which can be loaded onto the amplifier if the correct motor model number is
selected in the setup wizard. Therefore, extensive tuning to adjust these three parameters
is not necessary. During a test where the controller’s PID is set to zero, an open-loop
voltage step input is fed to the amplifier, and the actual velocity plotted – setting DVBW
value to 70 (default is 50) seems to improve the motor’s response considerably.
SGVRAT1 and SGINTE1 default values remain. Once again, due to the high torquedensity
packaging of the motor, the Auto Crossover Frequency test, which involves pulse
inputs to the drive, does not work well in the velocity mode. This holds true even when
the pulse magnitude in the Edit/Crossover Tuning Parameters is set to 0.5V. The digital
‘smart’ drive expects the motor to be at a certain velocity with each given pulse input
instantly, but high friction in the motor makes it impossible. To close up on this velocity,
the drive would falsely put in an increased voltage, which results in extreme instability on
the motor. The best tuning method for this mode is the Point-to-Point test, which gives a
settling time of 4ms and a maximum overshoot of 25 counts during a 1000-count move.
Note: In the event that a tuning method dose not work properly, go to the Edit menu and
try changing the tuning parameters to more closely resemble the actual environment in
which the motor is going to be operating. Contact an application engineer at Galil for
assistance in tuning the Galil filter.
Galil Motion Control, Inc. • 3750 Atherton Road • Rocklin, CA 95765 USA • 800-377-6329 • Ph: 916-626-0101 • Fax: 916-626-0102 • www.galilmc.com