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Author Topic: Spindle indexing/timing setup  (Read 4748 times)

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Spindle indexing/timing setup
« on: February 15, 2009, 04:43:32 PM »
Hi All,
I’m setting up my small mill and I want to monitor the rpms of my spindle drive motor. It’s easy to use the “index” option in the “input pins” for a once per revolution reading but there seems to be no way to scale the result.

Here’s what I did to test it out. I sent a 100 Hz. Pulse, 3msec. width, 5 Vpk to pk, from an Agilent ARB.waveform generator to an LPT port (I used pin 11) to see what Mach 3 would show. It showed 6000 rpms. That translates to 1/100 = 10 msec for each pulse or as expected 100 pulses per second at 60 sec = 6,000.

That’s all well and good but I want to set up a disk with 6 or 8 divisions for better accuracy.

Art’s information says you can use the “timing” in the “input pins” config. but he gives no information on how to do this that I can find.

If I set the timing pin to a port, say the same port I used for the index I get no rpm reading in Mach 3 for spindle rpms.  I can set both the index and the timing pin to pin 15 but this just gives me my 6,000 rpms. If I go to the “Calibrate Spindle” screen the “pulses per revolution” can not be changed, so there must be something I’m missing.

I did go into the pulley section but this is not applicable to this.

Any help is appreciated.

I wish Art would straighten this out or give us a method to resolve it. I’ve searched extensively and no one seems to have an answer for this.

Thanks,
Rob
« Last Edit: February 15, 2009, 04:46:16 PM by Robaroni »

Offline Hood

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Re: Spindle indexing/timing setup
« Reply #1 on: February 15, 2009, 04:59:50 PM »
You will probably not get more accuracy but you can do it if you wish. The Index was intended mainly for lathe threading so that the extra slots could be used to calculate in between the main pulse, however all the extra calcs basically made it no better.
 So anyway if you wish to use the timing input what you need is one slot to be at least 50% wider than the rest and Mach will calc the amount of slots itself.
Hood
« Last Edit: February 15, 2009, 05:02:02 PM by Hood »
Re: Spindle indexing/timing setup
« Reply #2 on: February 15, 2009, 05:16:20 PM »
Thanks for the tip.
That's exactly what I wanted to use it for, threading but I guess I'll have to servo the axis.
One more thing. If I set the pulley to 1, that is no ratio then should my readout show the same spindle speed as rpms?

Offline Hood

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Re: Spindle indexing/timing setup
« Reply #3 on: February 15, 2009, 05:19:41 PM »
You can thread no problem at all with a single index pulse :)
Yes pulley ratio of 1 will read whatever your index pulse is doing.
Hood