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Author Topic: Hysterese  (Read 7517 times)

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Offline jaja

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Hysterese
« on: June 22, 2009, 05:19:57 PM »
Dear reader,

I want to put an optical device and some reflecting tape on the spindle axis, to generate a pulse for mach to control the spindle speed.
A friend told me there could be some sort of "bouncing", a very fast on and off switching, when the border of the tape passes the optical device.
Is there a way mach could deal with this situation, or do I have to filter out this noise, before sending it to mach?

I thought it could be controlled with the "inputs signal debouncing/noise rejection" on the general logic configuration screen.
Luckely this friend is very good in electronics, and capable of building some sort of filter to give a nice straight signal to mach,,,,, but is this necessary????

gr jaja

Offline Hood

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Re: Hysterese
« Reply #1 on: June 22, 2009, 06:16:23 PM »
There is  a seperate debounce setting for the index pulse, also you can have averaging set. Not sure if thats what you are after?
Hood

Offline RICH

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Re: Hysterese
« Reply #2 on: June 22, 2009, 08:16:10 PM »
jaja,
No electronics guy so my explanation will get stupid real quick.    ;D
Ask your electronics friend to explain hysteresis. My take is that you can get a ramping and overshoot on the square wave so that the triggering may sometimes vary from the low / high / low  of a square wave and thus you don't end up with consistant timing or nice clean pulse at two distinct voltages over a time period. 

So they clean the signal up with additional electronics.

If that's what you were meaning.  ;)
RICH

Offline jaja

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Re: Hysterese
« Reply #3 on: June 23, 2009, 11:31:42 AM »
Hood,
This is exactly my problem:  I'm not sure if that's what I'm after.
It is my question in other words.
I don't know if I need a special electronic device to make a nice straight signal,,, or is mach capable of dealing with a "noisy" one.

Rich gives a very accurate description of my problem, but the question still remains: do I need special electronics, or can mach handle it?

Hood and Rich, thanks for your reactions

gr jaja

Offline Hood

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Re: Hysterese
« Reply #4 on: June 23, 2009, 01:20:35 PM »
Mach certainly has no problems with the slotted disc and opto I use on the mill, I know quite a few others use reflective type optos and they dont have problems so you should probably be fine.
Hood

Offline jaja

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Re: Hysterese
« Reply #5 on: June 23, 2009, 04:54:18 PM »
Oke Hood,

Thanks, I'm going to try.
The closer one get to finish the work on the lathe, the more questions appear.

Here is another one:
The plus or minus from the jog cycle buttons are not working as a + or a -, the number goes from high to low, no matter if you hit the + or -,, strange.

gr jaja

Offline Hood

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Re: Hysterese
« Reply #6 on: June 23, 2009, 05:08:35 PM »
A axis on a lathe? or is this on a different machine?
Which buttons are you meaning, is it on the flyot screen when you press tab?
If you attach your xml I will test it here and see if I can find an issue.
Hood

Offline jaja

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Re: Hysterese
« Reply #7 on: June 23, 2009, 05:26:10 PM »
Hood,

Just the plus and minus button on the manual screen, under "jog cycle".
Hit the plus and the value gets lower instead of higher.

gr jaja

Offline Hood

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Re: Hysterese
« Reply #8 on: June 23, 2009, 05:36:49 PM »
Ah ok sorry thought you were meaning A  Axis jog when you said A+ and A-.
I dont use the standard lathe screenset but have just looked and both buttons are the same OEM code which is a cycle button to run through the increment, if you continue pressing either one it will go down to 0.0001 then back to 1.000 then 0.1000 etc etc. There is only a cycle button for this as far as I know so I have no idea why the screen has + and - buttons.
Hood

Offline jaja

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Re: Hysterese
« Reply #9 on: June 23, 2009, 05:44:20 PM »
Hood,

Thanks again,
It is clear now.
It is not a fault om my computer.

Is it possible to get more then 10 steps (increments) in this jog cycle?
And what sort of screenset do you use with your lathe? I'm curious.