View Full Version : 4th axis solution to solve gantry skewing, geckos and servo, and axxus questions


CuttersCov
02-20-2006, 01:03 PM
Okay here's my situation:

My gantry skews, solution: add another servo to the opposite side.

Problems: My controller is already built with 3 axis, and the servos I have are next to impossible to get.

The controller I have has 3 gecko 320s and obviously 3 servo motors, the breakout board (axxus technologies) has a output for a 4th axis labelled A axis.

?'s:

If I add another gecko can the motor I add be of a different type than the other 3?

Will I need to add an additional power supply to run 4 geckos and 4 motors?

Can 2 of 3 current motors be calibrated(in software) to run the x axis (keep in mind I think the motors have to turn in opposite directions) and if I have to install a 4th motor to drive the z axis can a separate drive/board/motor, be used?


Thanks,

Matt

Kookaburra
02-20-2006, 05:10 PM
Matt,

My Comments on your questions below.


My gantry skews, solution: add another servo to the opposite side. - Can be Done

Problems: My controller is already built with 3 axis, and the servos I have are next to impossible to get. Usually The case in home built CNC

The controller I have has 3 gecko 320s and obviously 3 servo motors, the breakout board (axxus technologies) has a output for a 4th axis labelled A axis. Can the A axis be slaved to another axis?

?'s:

If I add another gecko can the motor I add be of a different type than the other 3? Yes, but it would be beneficial for you if you could find a motor of the same voltage so you do not need to build another rectified transformer and you will need exactly the same PPR encoder as the oposite motor

Will I need to add an additional power supply to run 4 geckos and 4 motors? You will need to know what Amp output the transformer is to ensure this. Look at the maximum current draw of each motor in Amps, add them all together, which will tell you the very worst load you will draw. Bearing in mind that you will probable never fully load all motors to their maximum in a movement, it is usually safe to have a transformer with 75% of the worst case required Amps output. Others may disagree, but this is my rule of thumb.

Can 2 of 3 current motors be calibrated(in software) to run the x axis (keep in mind I think the motors have to turn in opposite directions) and if I have to install a 4th motor to drive the z axis can a separate drive/board/motor, be used? Using Geckos will probably mean you need to use your software (if it can be done in your software) to slave the two motors. There is another type of servo drive on the market that has a optional single axis input with dual axis monitored output drive board, but it is only available with their drives and will will not support Geckos.

Hope you find the answers you are looking for!