Stepper controlled coil winder

[Guy69]

Hi there
I built a first prototype of stepper controlled coil winder using the following architecture :

• PC interface in MS Excel
• VBA code to do the maths according to wire gauges, # turns etc
• Mscomm32.ocx to send communication to COM4 port
• FTI USBMOD4 device (http://www.elexol.com) to use USB interface
• Bit 0 pilots the coil stepper driver: Qasar 3179 unipolar driver (http://www.quasarelectronics.com) . Current regulation (4.5A) uses a simple and old-fashioned power resistor. The motor is 86HY62DE04 from http://www.3xmotor.com
• Bit 1 pilots the wire guide stepper driver: Qasar 3158 bipolar driver. The motor small motor has been salvaged from an old fax machine.

The system works BUT in my opinion the rotation is not smooth and regular. Sometimes the motor groans and waits. This is not satisfactory and I am seeking for advices.
In my opinion flaws could come from
• VBA + Mscomm32.ocx: not reliable enough?
• USBMOD4 interface: tuning of capacitors between RXE and RD?
• Qasar drivers?
• Motor Current regulation?
Can anyone of you give advices, feedback, hints?
MANY THANKS
Guy

[pminmo]

Maybe a combination of issues. USB has high latency, so you could possibly be seeing a variance of pulse timing. Second issue would be the full step Qasar driver, you would gain by going to at least half step, if not quarter or eighth. There is a lot of difference in motor smoothness between full and half step, and each subsequent microstep size.

[Dennis Bohlke]

Guy

The VBA is very unreliable when it comes to maintaining timing.

The USB has a built in 1 ms latency. That's the time between when you tell it to send data till it actually gets sent.

I had to add processor on USB end to get sweet step signals.

Dennis
http://www.super-tech.com

[Guy69]

Thanks Phil and Dennis.
I will then reconsider my architecture :-)
Thanks again,
Guy

[jjvogre@aol.com]

hey,

just curious if you have any pictures of the coiler. sounds like we're in the same field, I'm gonna be working on one of these too.... some day.

Hope to hear from you soon,
Jesse

[RICHARD ZASTROW]

I don't know how practical this would be. Kollmorgen (Danaher) has a motor type called "servo-disc". They claim zero cogging at 1 rev. per DAY. Some are in kitmotor form.

Dick Z