Geckodrive

G201 REV-16

Last Update: August 6, 2009

Click here to download this manual (PDF)

Thank you for purchasing the G201 drive. The G201 microstep drive is warranted to be free of manufacturing defects for 1 year from the date of purchase. Also anyone who is dissatisfied with it or is unable to make it work will be cheerfully refunded the purchase price if the G201 is returned within 15 days of the purchase date.

PLEASE READ FIRST BEFORE USING THE G201

Before beginning, be sure to have a suitable step motor, a DC power supply suitable for the motor and a current set resistor. The motor’s rated phase current must be between 0.3 Amp and 7 Amps. The power supply voltage must be between 4 times and 20 times the motor’s rated voltage. The current set resistor may be a 1/4 Watt, 5% part. Finally have a STEP and DIRECTION pulse source available.

G201 TERMINAL WIRING

The G201 uses a 2-piece modular main connector. The connector is split in two pieces; terminals 1 through 6 (power supply and motor leads) and terminals 7 through 12 (control interface). Each can be removed separately by pulling the connector body upwards and off of the mating header pins on the G201. The connectors must initially be removed to mount the G201 to a heatsink or chassis.

TERMINAL 1 Power Ground
Connect the negative (black) lead of your power supply to this terminal.

TERMINAL 2 Power (+)
Connect the positive (red) lead of your power supply to this terminal. It must be between +24VDC to +80VDC.

TERMINAL 3 Motor Phase A
Connect one end of your “Phase A” motor winding here.

TERMINAL 4 Motor Phase /A
Connect the other end of your “Phase A” motor winding here.

TERMINAL 5 Motor Phase B
Connect one end of your “Phase B” motor winding here.

TERMINAL 6 Motor Phase /B
Connect the other end of your “Phase B” motor winding here.

TERMINAL 7 Disable
This terminal will force the winding currents to zero when shorted to ground (TERMINAL 12).

TERMINAL 8 Direction
Connect the DIRECTION signal to this terminal.

TERMINAL 9 Step
Connect the STEP signal to this terminal.

TERMINAL 10 Common
Connect the controller’s +5VDC supply to this terminal.

TERMINAL 11 Current Set
Connect one end of your current set resistor to this terminal.

TERMINAL 12 Current Set
Connect the other end of your current set resistor to this terminal.

POWER SUPPLY HOOKUP

TERMINAL 1 Power Ground
Connect the power supply ground to term.1

TERMINAL 2 Power (+)
Connect the power supply “+” to this terminal

The power supply voltage must be between 24 VDC and 80 VDC. The maximum power supply current required is 67% of the motor’s rated phase current. An unregulated power supply may be used as long as the voltage stays between the limits; keep the ripple voltage to 10% or less for best results. The drive has a 2 second power-on reset time before the motor is energized.

CAUTION! Power supply voltage in excess of 80 VDC will damage the G201.

If the power supply is more than 1 foot (300 mm) away from the G201, a 470uF capacitor must be connected across the G201’s power supply terminals. Keep the capacitor lead length to 1 inch (25 mm) or less.

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 high speed performance required of 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 25 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 the motor’s rated voltage. A power supply voltage greater than 25 times the motor’s rated voltage will overheat and damage the motor, even if it is not turning. Motor winding inductance should be 500uH or greater, but generally no more than 7mH.

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

MOTOR CONNECTION

TERMINAL 3 Phase A
Connect one motor winding to this terminal

TERMINAL 4 Phase /A
Connect the other end of the winding to this terminal

TERMINAL 5 Phase B
Connect the other motor winding to this terminal

TERMINAL 6 Phase /B
Connect the other end of the winding to this terminal

Connect one motor winding to terminals 3 and 4. Connect the other winding to terminals 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 terminals 3 and 4.

CAUTION! Do not short the motor leads to each other or to ground; damage will result to the G201.

4-wire, 6-wire and 8-wire motor may be used. When 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.

DISABLE PIN

TERMINAL 7 Disable
This terminal will force the winding currents to zero when shorted to ground (TERMINAL 12).

Shorting this input to ground (term. 7 to 12) forces winding currents to zero and stops all output switching activity. The G201 will continue totalizing step and direction inputs if any are sent. The power supply current drops to less than 15mA. The motor will return to its original position when the disable input is released if no step pulses have been sent and the motor has not been moved more than 2 full steps.

STEP AND DIRECTION INPUTS

TERMINAL 8 Direction
Connect the DIRECTION line to this terminal.

TERMINAL 9 Step
Connect the STEP line to this terminal.

TERMINAL 10 Common
Connect this terminal to the controller +5VDC power supply

These inputs are optically isolated from the rest of the drive. Terminal 10 is the common anode connection for the opto-isolators and must be connected to the +5 VDC supply of your indexer or pulse generator.

These inputs are meant to be driven by standard TTL logic or other driver capable of sinking 16mA of current. The minimum logic “0” time is .5uS while the minimum logic “1” time is 4uS. Microstepping occurs on the falling edge of the step input.

CURRENT SET RESISTOR

TERMINAL 11 Current Set
Connect the current set resistor to this terminal.

TERMINAL 12 Current Set
Connect the other end of the current set resistor to this terminal.

This input programs the G201A’s current output to the motor windings. The G201 will accommodate motor winding currents from 1 to 7A and 0.3 to 2A. Use the following equation to calculate the value, (in kilo-ohms) of the current set resistor:
R (in kilo-ohms) = 47 * I / (7 – I) or for the low current range, R = 47 * I / (2 – I)

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

HEATSINKING

The G201 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 to 50 degrees or less. Use heatsink compound between the G201 and the heatsink.

CAUTION! Current settings above 3 Amps without a heatsink will result in damage to the G201.

The drive must be heatsinked to a piece of aluminum, preferably with fins and a fan to increase heat dissipation and surface area. Do not screw the drives directly to the door of your control cabinet, as this will typically not provide adequate heatsinking properties.

OPTION JUMER BLOCK

The G201 has four settable options. These options are enabled and disabled via the jumper block shunt settings. See the diagram below for how to set the shunts. The four options are described below.

(1) AUTO CURRENT REDUCTION: The G201 reduces motor phase current to 33% of the set value when the motor is stopped. If enabled, this reduction occurs 1 second after the last step pulse is sent to the drive. Auto current reduction can be enabled or disabled.

(2) REDUCED CURRENT RANGE: In addition to the normal current range (1A to 7A), the G201 can also operate over a reduced current range (0.3A to 2A). This range is used for motor phase currents of less than 1A. Auto current reduction is not available for this reduced current range.

(3) NEMA-42 MOTOR: Use this option if the drive is to be used with NEMA-42 frame size motors. This option adjusts the mid-band compensation circuit for optimum performance with this size motor.

(4) MID-BAND COMPENSATION DISABLE: Some step pulse sources generate very “ragged” timing. If the pulse-to-pulse period varies by more than +/-30%, the drive may have problems counting that step pulse. This option disables the mid-band compensation circuit, making the drive insensitive to this timing restriction. As a consequence, the motor may exhibit mid-band instability problems.

ADJUST: This trimpot adjusts the motor for the smoothest possible low-speed operation. Set the motor speed to about 1/4 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.




CONVERTING THE G201 TO A G210

The G201 can be converted to a G210 by installing the G901 step pulse multiplier board. Remove the cover of the drive, and then use a small pair of needle-nose pliers to remove the opto-isolator from its socket. Plug the G901 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.



SPECIFICATIONS

Supply Voltage:                     24 to 80 VDC
Phase Current:                     1 to 7 Amps and 0.3 to 2 Amps (2 ranges)
Auto Current Reduction:     33% 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)
Quiescent Current:              15 Ma or less
Weight:                                   3.6 oz. (100 gm)
Step Frequency:                   0 to 200 kHz
Step Pulse “0” Time:           0.5 uS min (Step on falling edge)
Step Pulse “1” Time:           4 uS min
Temperature Range:          0 to 70 C
Humidity:                               0 to 95 % (non-condensing)
Direction Setup:                   1 uS min (20 uS min hold time after Step edge)
Power Dissipation:             1 to 18 W (1 to 7 Amps)


RESTORING FACTORY DEFAULTS

To restore the G201 to the factory settings set the trimpot to the 11 o’clock position and put the jumpers on “STANDBY ENABLE” and “NORMAL” on the option jumper block.

DISCLAIMER

CERTAIN APPLICATIONS USING POWER PRODUCTS MAY INVOLVE POTENTIAL RISKS OF DEATH, PERSONAL INJURY OR SEVERE DAMAGE TO PROPERTY. GECKODRIVE INC. PRODUCTS ARE NOT DESIGNED, AUTHORIZED OR WARRANTED TO BE SUITABLE FOR USE IN LIFE-SUPPORT DEVICES OR OTHER CRITICAL APPLICATIONS. INCLUSION OF GECKODRIVE INC. PRODUCTS IN SUCH APPLICATIONS IS UNDERSTOOD TO BE FULLY AT THE PURCHASER’S OWN RISK

In order to minimize risks associated with the purchaser’s application, adequate design and operating safeguards must be provided by the purchaser to minimize inherent or procedural hazards. GECKODRIVE INC. assumes no liability for applications assistance or the purchaser’s product design. GECKODRIVE INC. does not warrant or represent that any license, either express or implied, is granted under any patent right, copyright or other intellectual property right of GECKODRIVE INC.