Spindle control problem

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27 May 2011 20:48 #10115 by flintmill
I have just converted my Taig mill to EMC from using Turbocad under windows and all seems to be well apart from the spindle control.
On Turbocnc this worked quite well. it consists of a transistor interface driving a SCR which feeds the AC motor.

However on EMC I get no off position, the speed of the motor just seems to drop slightly and the noise changes.

I assume that spindle on or spindle off just changes the voltage on the out pin. It seems as though it is being pulsed rather than a steady level.

Anyone any ideas what I am doing wrong

John

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27 May 2011 21:53 #10117 by BigJohnT
Replied by BigJohnT on topic Re:Spindle control problem
How did you configure the spindle on/off?

John

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27 May 2011 23:29 #10119 by andypugh
Replied by andypugh on topic Re:Spindle control problem
Can you show us your HAL file?

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28 May 2011 08:05 #10122 by flintmill
I used the wizard that came with EMC2 to set up as for Xylotex then chose the pin I use as output for my spindle and set it to spindle on.
When it didn't work properly I changed the timings to those of Sherline which seem to be about 10 times longer but still failed.

The machine I use is not on the net as it is so far from the wifi in the house . Will try and get Hal files to put up later today

Thanks john

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28 May 2011 09:42 #10123 by cncbasher
you will probably find the voltage is not dropping far enough to switch the SCR off , this can be down to bias resistor , and other reasons . are you familiar with electroncs then it is an easy fix
this also in part reflects on how you are connecting and which breakout board interface you are using , and voltages

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28 May 2011 10:49 #10124 by flintmill
Here is the Hal file after updating. I cant see any obvious problem. My next step will be to measure the output voltage on the pin of the old windows/dos laptop and then on the newer Linux one to see if the 0 and 1 voltages are the same
John

File Attachment:

File Name: Taig_mill.hal
File Size:3 KB
Attachments:

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28 May 2011 10:52 #10125 by flintmill
Just seen your post after putting up HAL file. i think you aare correct. I was so pleased with the way EMC2 loaded and worked in terms of driving my steppers(so much smoother than Turbocnc ) that I forgot the obvious fact that I had changed machines

John

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28 May 2011 10:57 #10126 by BigJohnT
Replied by BigJohnT on topic Re:Spindle control problem
Could be that two different computers parallel ports have different voltages and pull up/down characteristics.

Are you not using a breakoutboard? I would not connect a CNC machine directly to the parallel port and risk burning it out unless it is a PCI card.

John

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28 May 2011 12:56 #10129 by andypugh
Replied by andypugh on topic Re:Spindle control problem
flintmill wrote:

Here is the Hal file after updating. I cant see any obvious problem.

It certainly looks OK from the point of view of turning the spindle on and off.
You have a spurious adir signal defined and linked to a pin, but that won't matter.
I am not completely sure that you want estop-out linked to pin1, but that rather depend son what pin1 does in hardware.

As you have concluded, it probably is a problem with driving the SCR. I would be tempted to add an opto-isolator (or maybe a ULN2003, maybe even a transistor depending on what I had lying about) to buffer the signal.

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28 May 2011 14:31 #10131 by flintmill
Just undone the box to see where I was and find I HAD isolated the spindle with a K3020 opto isolator which is rated at 15ma to 30 ma at 3V with 150ohm input resistor for the LED so I assume it must be be voltage issue from this laptop. So will have to redesign the O/P circuit when I have measured what the wretched machine is actually doing.
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