# Choosing a Drive

Choosing a Drive

Which Geckodrive is Best For Me?

Section 1: Choosing Stepper or Servo

To determine which of our drives is best suited to your machine and
motor, you must first decide between a stepper or a servo motor system.
Consider using a stepper motor if less than 100 watts is required, a servo if 200 watts or more are required and either type between 100 watts and 200 watts. To determine the amount of watts needed, you must first determine several factors about your machine:

• The weight of the heaviest object being moved: This will typically be your gantry and, for this example, we will use a gantry with the weight of 40 pounds.
• Inches per minute desired: This is a number that will make you deliriously happy with the performance of your machine and, for this example we will use 1000 IPM.

Now multiply IPM and pounds together and divide that number by the normalizing constant of 531. The answer will be the total number of watts needed for your machine. Below is the formula in basic form:

(Heaviest object * IPM) / 531 = Watts required

And solved for the numbers above:

(40 * 1000) / 531 = 75.329W

Because this number is below 100W, you will definitely want to stay in stepper territory.

If your answer was below 100W, then go to Section 2.

If your answer was above 200W, then go to Section 3.

If it was between 100W and 200W, go to Section 4.

Section 2: Stepper Drives

Geckodrive currently offers eight stepper motor drivers. We have our high current drives which go up to 7A, and our low current drives which go up to 3.5A. If your motor is above 3.5A, your drive options are the G201X, G203V, G210X and G213V.

First you must determine the maximum step pulse frequency of your step pulse source (CNC program, PLC, etc.); if it is below 25kHz, we recommend using a step pulse multiplier equipped drive, such as the G210X or G213V. The G210X is a G201X with a step pulse multiplier onboard, and offers the same specifications as the G201X and adds the choice of full step, half step, 5uStep and 10uStep (default). This is useful for low source (CNC program, PLC, etc.) step pulse frequencies, as mentioned above. The G213V is a G203V with a step pulse multiplier and does the same as a G210 but offers short circuit protection as well as many other protections against the most common failures.

If your step pulse frequency is above 25kHz, your motor is between 0A and 7A, and you do not need full step, half step, or 5uStep operation, then you can use a G203V or the G201X. The only functional difference between the two is the level of protection they offer; the G203V is protected against almost all possible failures while the G201X is not protected. If connected correctly and in a safe and clean environment, the G201X will function identically to the G203V.

If your motor is below 3.5A, you can use the above drives as well as the G250, G251 or G540 drives. The G250 and G251 do not have short circuit protection. The G250 has a 2x15 pin connector, while the G251 has a 12 pin, 3.5mm connector, operating exactly the same as a miniature G201X.

If you need an all in one solution then the G540 is the drive for you. It has a built in breakout board, short circuit protection, opto-isolation, parallel port connection and four axis operation via DB9 motor cable connectors.

Section 3: Servo Drives

The G320X is Geckodrive's newest servo drive and is a more advanced replacement for the G340.

The G320X has an onboard step pulse multiplier, which allows the user to select between a multiplier of 1, 2, 5 or 10. What this means is the number of pulses will be multiplied by the selected jumper setting. An example would be if you have it on the 5 setting, it will move 5 pulses for every pulse sent, thereby dividing your encoder line count by 5. You get speed at the sake of resolution and the easy way to get speed and resolution is to supply a higher step pulse frequency.

Section 4: Either Stepper or Servo

Because you fall between the territory for steppers and servos, you have the option of both. You will be operating at the high end for steppers and the low end for servos; and both will cost approximately the same to set up. When you decide which type of motor you would like to use, go ahead and skip to the appropriate section above.