Change gearing sign (reverse slave axis)

[Emme]

Hello,

I am building a precision winding machine: the mater motor controls a cylinder and the slave motor movese the head with the wire. The objective is to wind the wire in a 3d helix. I am using a cRIO 9022 with two NI 9512 drivers.

The problem is that I need to be able to change the gearing sign, so that I can do clockwise and counterclockwise helixes but always move the master motor (and the cylinder) in the same direction (the winding machine is built so that the wire should only be pulled in one direction).

I have tried reversing the sign of the numerator in the gearing VI to get the slave motor to move in reverse but this does not seem to work. The only solution I have found is to reverse the motor phase by swapping the A and Abar wires in the 9512 driver. 

I can attach a copy of the project if needed.

[Cla_Cup]

Hi Emme,

sorry but I don't understand what is your purpose. What kind of motors are you driving? Do you need to keep the rotation direction constant, and chenge only the slave motor rotation direction?

Do you need to do this programmatically? What kind of motors are you using? What kind of drives? Are you using FPGA?

Let me know.

Best Regards

CLA

[Edwin_Wise]

Looking at the SoftMotion Multi-Axis Gearing example (Function Block or Express VI versions), I do see the numerator with a negative value and the slave axis then moves in the opposite direction from the master axis.  I would expect this to work with motors as well as the simulated axes I'm looking at.

Some questions: 

Are you using SoftMotion? Which version of the software are you using?

Are you trying to change the gearing during operation, or do you set a ratio and run with it through the full operation?

It might be useful to see the project, as you offered.

Thanks,

Edwin!