Mach newbie changing axis direction and lowering encoder count

[toadjammer]

I am doing a retrofit on a bridgeport and am having some issues.

This is what I have: original servos with US digital 500 encoders, gecko 320X, CNC4PC C10.

The table and spindle moves in the wrong direction X- when trying to move X+. I tried swapping the armetur pos and neg but the motors start to self drive with no signal to tell them to move. Is there a parameter or setting that can be changed to switch this?

With the 500 cpr endcoders and the pullies and lead screw that is stock I have to set the steps per unit at 20000 to achieve 1 inch of movement. ANd I have verified that I am not using the pulse multiplier on the geckos. When I input that information into the motor settup my speed is limited to 75 IPM. How can I change this to achieve more speed through Mach?

Thanks
Toad

[awerby]

Originally Posted by toadjammer I am doing a retrofit on a bridgeport and am having some issues. This is what I have: original servos with US digital 500 encoders, gecko 320X, CNC4PC C10. The table and spindle moves in the wrong direction X- when trying to move X+. I tried swapping the armetur pos and neg but the motors start to self drive with no signal to tell them to move. Is there a parameter or setting that can be changed to switch this? [Yes; in Config/Ports and Pins/ Motor Outputs switch the direction bit - if it's high active make it low, if it's low active make it high. This should change the motor direction. (Put the motor itself back the way it was.)] With the 500 cpr endcoders and the pullies and lead screw that is stock I have to set the steps per unit at 20000 to achieve 1 inch of movement. ANd I have verified that I am not using the pulse multiplier on the geckos. When I input that information into the motor settup my speed is limited to 75 IPM. How can I change this to achieve more speed through Mach? Thanks Toad

[The step pulse multiplier is your friend here. Your high encoder count is limiting your speed. Set the jumper to give you a factor of two, and you should double your speed - it will double the rate it sends pulses to the motors. The other way to do that is to increase your kernal frequency, which won't compromise resolution (although it sounds like you've got resolution to spare). Here's a quote from the Geckodrive site (it's about the G340, but it's pretty much the same for your G320X):]

"The G340's step pulse multiplier, the G902, 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.

The G340 should only be used if you are already stuck with a high resolution encoder and a low maximum frequency step pulse signal."

[Let us know if that does the trick, okay?]

Andrew Werby
ComputerSculpture.com — Home Page for Discount Hardware & Software

[toadjammer]

Thanks.

toatally misunderstood the pulse multiplier.

And after doing some more searching figured out how to invert the feed direction.

Now if I could figure out some other issues...going to look around some more.

Thanks
Toad