Author Topic: Help with Mach3 interface problem  (Read 2982 times)

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Offline fuelsguy

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Help with Mach3 interface problem
« on: May 22, 2009, 03:18:07 PM »
I'm new to CNC so I'm learning a lot as I go. I have just finished a build of a woodworking router, and I have a problem. I have installed a breakout board, FET4, from Stepperworld and 23 size motors. I have been having trouble getting the steps per inch set. I am getting very inconsistent results.
 For a set-up that should be at 2000 steps per inch I was getting values in the 3000 range from the steps per inch test in Mach3 and inconsistent results.
After some trouble shooting and concerns that there was too much friction in the router I went back to basics to understand the no-load responses of the system.
I disconnected the lead screws from the motors to avoid any torque issues. Using the simple test software from Stepperworld I got consistent results, 200 steps  gives me 360 degrees of rotation, 2000 steps  gives me ten rotations. This was repeatable and consistent. I tried full speed and I get around 100 rpm. This worked on all three axes.
All good news.
However, when I use Mach3 and set the steps-per-inch to 2000, and ask for an inch of travel, I get a rotation between six and seven revolutions instead of the ten revolutions expected. The amount of rotation is very variable when repeated.
 I have about 4 ft of wiring to each motor in separate harnesses between the board and each of the motors.
Since the test software behaves correctly, I'm stuck trying to figure out what to try next with Mach3 to cure the problem.
I am going to try a short harness (just the wires attached to a motor connected to the board) to see if the harness has a problem.

Any suggestions would be appreciated.


Ivor

Offline Hood

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Re: Help with Mach3 interface problem
« Reply #1 on: May 22, 2009, 03:31:30 PM »
Lower the accel and Velocity and see if that helps.
Hood

Offline fuelsguy

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Re: Help with Mach3 interface problem
« Reply #2 on: May 22, 2009, 03:55:26 PM »
Hood, I'm way down on speed and accel already, 5 inches per min and 3 (whatever the accel units are)
I did try a short harness and got the same results, normal operation with the Stepperworld test software and about 60% requested travel with Mach3.
I have no idea what to try next. I think about connector problems but why does the test software work OK? It's not a torque issue as there isn't any. So I'm left with Mach3 and is there any switch I've set incorrectly? I'm a real beginner with mach3 so there could be a setting issue if I knew where to look.

Any ideas welcome!

Ivor

Offline Hood

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Re: Help with Mach3 interface problem
« Reply #3 on: May 22, 2009, 04:38:39 PM »
If you have the Pulse widths at zero try increasing to 5.
Hood

Offline fuelsguy

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Re: Help with Mach3 interface problem
« Reply #4 on: May 22, 2009, 09:30:02 PM »
Hood,
 Thank you for the suggestion. I tried it and it seems to be working. I say "seems to be" as I haven't had time to do a thorough check. The motors sound a lot better and I can get up to 18 inches per minute travel on the y axis. I haven't tried the others yet.. Since this is the Memorial Day three day weekend here in the States I'm not likely to get back to the shop until Tuesday. I'll follow up then with more data.

If it works I'll owe you a single malt sometime.

Ivor