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Messages - TonyP

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91
General Mach Discussion / Re: Need a little spindle encoder timing help
« on: December 18, 2007, 01:26:17 PM »
Here's a strange thing. I've been sitting here playing with my machine & trying different things in the spindle setup. I eventually got into a mode where I couldn't get the speed up to normal. I tried all the various tricks we've been discussing but no change. I eventually copied yesterday's latest xml file from the xmlbackups directory (MacTurn.xb99 in my case), renamed  the current one in the root, and replaced it with the copy (suitably renamed). Ran up Mach again & all ok. No visible changes in the settings.

It's a useful thing to remember that when you save a setup, the old one goes into the backup directory.
I'm a bit concerned that things that I can't see are being stored. I suspect the spindle calibration data.

Tony

92
General Mach Discussion / Re: Need a little spindle encoder timing help
« on: December 18, 2007, 12:36:37 PM »
What happens if you disconnect the feed to the VFD & measure the voltage? I would expect it to rise a little, but not very much. (showing that the VFD is not loading the analogue output)
I suppose you haven't played with the spindle calibration function. That can produce weird results, I don't think it works very well, myself. Click on defaults just in case. It doesn't tell you its done anything, but I think it removes any 'calibration' corrections that are applied. I haven't been able to find where the corrections are stored so that I can verify it. I suppose they should be in the xml file, but I can't see them.
There is a readout just below true speed on the manual screen, make sue that this reads 100% by pressing the adjacent reset button. This gets set to some odd values sometimes and will give you an incorrect speed.

Keep at it, we'll get there in the end!

Tony

93
General Mach Discussion / Re: Need a little spindle encoder timing help
« on: December 18, 2007, 12:00:59 PM »
Right, the number 2 assumes a 2:1 step down to the spindle. In closed loop with S=500 say and ratio set to 1, the spindle will run up to 500 and the true speed will read 500. With a ratio of 2 the motor will run up to 1000, but the true speed reading will be 500. This is to take account of sensors that are not on the spindle, but on the motor. If your sensor is on the spindle, the ratio should always be 1.

Tony

94
General Mach Discussion / Re: E-stop & reset question
« on: December 18, 2007, 04:41:09 AM »
Ryan,
I've now actually tried both the Reset code & the Charge pump off feature on my own system & it works fine.


Tony

95
General Mach Discussion / Re: Need a little spindle encoder timing help
« on: December 18, 2007, 04:34:54 AM »
Forget the last post _ your'e obviously getting on ok on that problem!

Tony

96
General Mach Discussion / Re: Need a little spindle encoder timing help
« on: December 18, 2007, 04:30:47 AM »
If you have a pulley set with anything other than a ratio of 1. Mach will use that ratio. Make sure that you havent selected a strange pulley. 
If you call the max speed of your drive does the DC level on the control output reach 10v? I believe there is an adjustment for that on the board.

Tony

97
General Mach Discussion / Re: Need a little spindle encoder timing help
« on: December 17, 2007, 03:28:01 PM »
Hmm,

I think there are two different problems.
 One: you don't seem to have a reasonable control of the motor speed.
Two: The index seems to give the wrong results.
I think it would be wise to separate the problems by not using the feedback etc. until you have  positive control of the spindle.
I assume the PWM signal is fed direct to the drive & not converted to a variable DC? On my system I use the step signal and convert it into a variable DC, which is what my drive needs.
Do you know what range of input your drive needs? ( either DC or PWM)

Tony

98
General Mach Discussion / Re: Need a little spindle encoder timing help
« on: December 17, 2007, 01:22:47 PM »
From what you said earlier you have control of the speed from Mach I think. Have you set 'use feed back etc' . in spindle config? Sounds as though you've got control, but haven't closed the loop.

Tony

99
General Mach Discussion / Re: Need a little spindle encoder timing help
« on: December 17, 2007, 11:16:39 AM »
Have you got Index pulse debounce (general config) set to something sensible? Say 4 ( 4x40us)


Tony

100
General Mach Discussion / Re: E-stop & reset question
« on: December 17, 2007, 05:03:15 AM »
Hi

it is possible do do what you describe. The circuit depends a bit on what you have. Is there a charge pump in operation & has it a contact output, or just a logic level?
The Mach reset should be available on OEM button code 1021, so assigning an input pin to produce that code should do the PC reset. The physical button on the machine that operates the pin will also reset a local latched relay that enables the drives.
If you want the PC to drop the latch out, then including the charge pump contact in the latch circuit will do it. Just make sure that 'Charge pump on in Estop' is not checked in General Config.
I prefer to have the latch tripped locally by physical switch contacts, but the charge pump should still be included in the circuit so that a problem at PC or control will stop things dead.

Hope this helps. I may be able to give you a fragment of circuit when I have some time later on.


Tony

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