Geckodrive G203V Quick start guide

G203V VACUUM INSTALLATION NOTES:
(April 29, 2008)
Thank you for purchasing the G203V drive. The G203V is Geckodrive’s new generation CPLD-based microstep
drive. It has short-circuit protection for the motor outputs, over-voltage and under-voltage protection, over-
temperature protection, reversed power supply polarity protection and will survive accidental motor disconnects
while powered-up. The “V” in G203V stands for “Vampire” as in unkillable.
The G203V uses a synchronous PWM design that is absolutely silent when the motor is stopped or turning slowly.
It virtually eliminates stopped-motor heating regardless of power supply voltage. The G203V is a jumper-free drive.
There are no internal user settings at all so there is no need to ever remove the drive cover at all.
The STEP, DIRECTION and DISABLE inputs are opto-isolated. All three inputs work with 2.5V, 3.3V or 5V logic
drive signals. The input drive current is now 2.5mA at 2.5V so almost all logic family (74LS, 74HC, etc.) can be
used to drive these inputs. The COMMON return for the signals is controller ground referenced instead of +5VDC.
This greatly eases the drive to controller interface.
There are no unusual STEP to DIRECTION timing restrictions. Stepping occurs on the positive edge of the STEP
pulse. The DIRECTION input must be true 200nS before and after this STEP pulse edge.
The G203V Microstep drive is warranted to be free of manufacturing defects for 1 year from the date of purchase.
Anyone who is dissatisfied with it or is unable to make it work to their satisfaction for any reason will be cheerfully
refunded the purchase price (but not shipping costs) if the G203V is returned within 15 days of the purchase date in
a cosmetically and electrically undamaged condition.
PLEASE READ FIRST BEFORE USING THE G203V
Before you start you must have a 2-phase hybrid PM step motor (ordinary 1.8 or 0.9 degree per step motor), a DC
power supply suitable for the motor and a current set resistor. The motor’s rated phase current must not be more
than 7 Amps. The power supply voltage must be between 15VDC and 80VDC unregulated. The current set resistor
may be a 1/4-Watt, 5% part. Finally have a STEP, DIRECTION and DISABLE (if needed) source available.
G203V TERMINAL WIRING
TERMINAL BLOCK WIRING:
(TERM. 1) POWER GROUND Connect the power supply ground to term.1
(TERM. 2) +15 TO 80 VDC Connect the power supply “+” to this terminal
The power supply voltage must be between 15 VDC and 80 VDC. The maximum power supply current required is
equal to the motor’s rated phase current. An unregulated power supply may be used so long as the voltage stays
between the specified limits; keep the power supply ripple voltage to 10% or less for best results.
CAUTION! Power supply voltage in excess of 80 VDC will blow the G203V internal fuse.
CAUTION! Reversed power supply polarity will blow the G203V internal fuse.
CAUTION! Never put a switch on the DC side of the power supply! This will damage, if not destroy, your drive!
The choice of power supply voltage depends on the required high-speed performance from the motor; doubling the
voltage doubles the motor’s high-speed power. In all cases the power supply voltage should be no less than 4
times or no more than 20 times the motor’s rated voltage. The motor may not run as smoothly as possible if the
power supply voltage is less than 4 times or more than 20 times the motor’s rated voltage. A power supply voltage
greater than 20 times the motor’s rated voltage may overheat and damage the motor. Motor winding inductance
should be 500 uH or greater.
A more accurate calculation of power supply voltage is to find your motor’s inductance, and put it into the following
equation.
32 * (√mH inductance) = Power Supply Voltage

If your motor has 2mH of inductance, the equation would look as follows.
32 * (√2) = 45.12V
(TERM. 3) PHASE A Connect one motor winding to this terminal
(TERM. 4) PHASE /A Connect the other end of the winding to this terminal
(TERM. 5) PHASE B Connect the other motor winding to this terminal
(TERM. 6) PHASE /B Connect the other end of the winding to this terminal
One motor winding connects to term. 3 and 4 and the other winding connects to term. 5 and 6. Turn the power
supply off when connecting or disconnecting the motor. If the motor turns in the wrong direction, reverse the motor
winding connections to term. 3 and 4.
CAUTION! Avoid shorting the motor leads to each other or to ground or the G203V will enter protective shut-down.
4-wire, 6-wire and 8-wire motor may be used. If 6-wire motors are used, they may be connected in half winding or
full winding. This is equivalent to an 8-wire motor connected in parallel or series. If a motor is connected in series
or full winding, the motor’s phase current rating is half of its parallel or unipolar rating. The choice depends on the
high-speed performance required; a parallel-connected motor will provide twice the power of a series-connected
motor at the same power supply voltage.
(TERM. 7) DISABLE Connect the DISABLE line to this terminal. Ignore this terminal if DISABLE is not used.
(TERM. 8) DIR Connect the DIRECTION line to this terminal.
(TERM. 9) STEP Connect the STEP line to this terminal.
(TERM. 10) COMMON Connect this terminal to the controller ground output.
These 3 inputs are optically isolated from the rest of the drive. They will operate with 2.5V, 3.3V or 5V logic outputs
with 2.5mA minimum source drive current. The STEP input’s maximum rated frequency is 300kHz with a 50% duty-
cycle waveform. The G203V steps the motor on the 0 to 1 logic (positive) edge of the STEP signal.
(TERM. 11) CURRENT SET Connect the current set resistor to this terminal
(TERM. 12) CURRENT SET Connect the other end of the current set resistor to this terminal
This input matches the G203V’s current output to the motor windings. The G203V will accommodate motor winding
currents from 0 to 7A. Use the following equation to calculate the value, (in kilo-Ohms) of the current set resistor:
R (in kilo-ohms) = 47 * I / (7 – I) Use the nearest standard value 5% tolerance, 1/4W resistor for this setting.
Here are the current set resistor values for motor current in .5A increments. Round the appropriate answer to the
nearest 5% resistor value.
a. 1A – 7.8K
b. 1.5A – 12.8K
c. 2A – 18.8K
d. 2.5A – 26.1K
e. 3A – 35.25K
f. 3.5A – 47K
g. 4A – 62.67K
h. 4.5A – 84.6K
i. 5A – 117.5K
j. 5.5A – 172.33K
k. 6A – 282K
l. 6.5A – 611K
m. 7A – OPEN
OTHER CONSIDERATIONS:
HEATSINKING: The G203V needs heatsinking for current settings greater than 3 amps. The case temperature
(measured on the bottom plate) should not exceed 70 degrees C, and for best life should be kept at 50C degrees
or less. Use heatsink compound between the G203V and your heatsink.
CAUTION! Current settings above 3A without a heatsink may result in the G203V entering thermal shutdown.

AUTO CURRENT REDUCTION: The G203V reduces motor phase current to 0% of the set current value 1 second
after the last step pulse is sent. The G203V also changes to a special recirculating current mode to nearly eliminate
motor heating.
ADJUST: This trimpot adjusts the motor for the smoothest possible low-speed operation. Set the motor speed to
about 1/2 revolution per second and then turn the trimpot until a distinct null is noted in the motor’s vibration. This
will result in the most even microstep placement for a given motor and power supply voltage. The default setting for
this trimpot is at ½ -turn and the setting for your motor will be within +/- ¼-turn of the default setting.
MAIN CONNECTOR: The G203V uses a 2-piece modular main connector. The connector is split in two pieces;
terminals 1 thru 6 (power supply and motor leads) and terminals 7 thru 12 (control interface). Each can be removed
separately by pulling the connector body up and away from the top surface of the G203V. Remove the connectors
to access the G203V front mounting screw locations in order to mount it to a heatsink or chassis.
G203V INDICATORS:
POWER LED: The GREEN POWER indicator is lit whenever the G203V has power supply voltage applied.
FULL POWER LED: The YELLOW FULL POWER indicator is lit when the motor is turning fast enough to generate
maximum possible mechanical power. Power is torque times RPM and power output reaches its maximum value
when this indicator is lit. Use this indicator to verify your motor is optimally geared to the load.
ERROR LED: The RED ERROR indicator is lit when:
1) During power-on reset for 1 second when power is first applied to the G203V.
2) While the DISABLE input is active.
3) When there is a short-circuit on any motor output. Momentarily activate the DISABLE input to reset.
4) During over-temperature shutdown. The LED automatically resets when the drive temperature drops.
INTERNAL FUSE: The G203V uses a socketed, user-replaceable internally mounted fuse (Littlefuse Inc. part #
0251005.MXL). Reversing the power supply polarity or a power supply voltage over 114VDC will cause the internal
fuse to blow.
CAUTION! Do not use any other type of fuse, do not bridge a blown fuse with wire and do not solder the fuse in
place. Doing so will void the drive’s warranty.
CONVERTING THE G203V TO A G213V: The G203V can be converted to a G213V by installing the G903 step
pulse multiplier board. Remove the cover of the drive, and then use a small pair of needle-nose pliers to remove
the optoisolator from its socket. Plug the G903 board into this socket and replace the cover.
REMOVING AND REPLACING THE COVER:
The STEP PULSE MULTIPLIER and the INPUT OPTION settings are jumpered internally. It is necessary to
remove the cover of the drive to change these settings from their default values. Please follow the steps below on
how to remove and replace the cover to avoid damaging the drive:
REMOVING THE COVER:
1) Remove the two 2-56 phillips-head screws on the bottom of the drive.
2) Gently lift the back of the cover upward until the LED clears the rectangular hole
3) Slide the cover backwards while still lifting until it clears the drive.
REPLACING THE COVER:
1) Make sure the LED is vertical relative to the drive printed circuit board.
2) Slide the cover forward over the drive while lifting the back of the cover.
3) When the cover is fully forward, look to see the LED is aligned with the hole.
4) Gently press the cover down, making sure the LED moves into the hole.
5) Replace the screws on the bottom of the drive.
It is recommended to use small needle-nose pliers or tweezers to move the jumpers on the internal headers.

MAIN CONNECTOR: The G203V uses a 2-piece modular main connector. The connector is split in two pieces;
terminals 1 thru 6 (power supply and motor leads) and terminals 7 thru 12 (control interface). Each can be removed
separately by pulling the connector body upwards and off of the mating header pins on the G203V. The connectors
must initially be removed to mount the G203V to a heatsink or chassis.
TROUBLESHOOTING:
EVERYTHING IS CONNECTED, NOTHING HAPPENS: Is the GREEN LED lit? If not, either the G203V has no
power supply voltage connected or something very bad caused its internal fuse to blow. Check the power supply
voltage using a multimeter set to ‘DC VOLTS’ on terminal screw heads 1,2 of the drive.
The internal fuse is the G203V’s final line of protection. It blows only under the most extreme circumstances. Those
are reversed power supply polarity; AC voltage instead of DC voltage on terminals 1,2 and power supply voltages
in excess of 114VDC. Correct the problem and replace the fuse with the only approved type. It is the only kind that
blows fast enough to protect the G203V. Anything else voids the warranty.
EVERYTHING IS CONNECTED, RED INDICATOR STAYS LIT: If the RED and GREEN indicator LEDs are lit then
the motor is miss-wired, the motor has a wire shorted to ground, is shorted to another motor wire or the motor is
bad. Secondarily: Everything ran OK but the RED LED lit a while later. Check the drive temperature; it may have
overheated because of inadequate heatsinking. Also see that the DISABLE input isn’t being activated (+5VDC on
DISABLE).
MOTOR HAS NO HOLDING TORQUE: If the RED LED is off and the GREEN LED is on, check the CURRENT
SET resistor with a multimeter. Re-calculate the resistor value. Check to see if the motor is connected to the
G203V.
MOTOR HAS HOLDING TORQUE BUT WON’T MOVE: Check your STEP, DIRECTION, DISABLE (if used) and
COMMON interface. Verify COMMON goes to your controller GND.
MY MOTOR RUNS ROUGH AT LOW SPEEDs: Try adjusting the ADJUST trimpot setting. Verify you are using the
correct CURRENT SET resistor. If you are using a ‘round’ motor, it won’t be as good as a ‘square’ motor.
MY YELLOW LED NEVER LIGHTS: You are not going fast enough to get full power from your motor. If you don’t
need to go any faster, use a lower power supply voltage. This indicator is a good application diagnostic for motor
gearing and power supply voltage choice. Using it correctly will help you to optimize your system.
SPECIFICATIONS:
Supply Voltage: 15 to 80 VDC
Phase Current: 0 to 7 Amps
Auto Current Reduction: 71% of set current, 1 second after last Step Pulse
Size: 2.5”W, 2.5”D, .85”H (63.5mm, 63.5mm, 21.5mm)
Mounting Pattern: 4 6-32 screws, 1.75” by 2.375” (44.5 mm, 60 mm)
Weight: 3.6 oz. (100 gm)
Quiescent Current: 20 Ma or less (drive disabled)
Short-circuit trip current: 10A, 3uS response time
Step Frequency: 0 to 333 kHz
Step Pulse “0” Time: 2uS min (Step on rising edge)
Temp: 0 to 70 C
Step Pulse “1” Time: 1 uS min
Humidity: 0 to 95 % (non-condensing)
Direction Setup: 200nS before step pulse rising edge
200nS hold after step pulse rising edge
Power Dissipation: 1 to 13 W (0 to 7 Amps)