Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: KB7CGA on January 15, 2011, 07:01:18 PM
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In mach 3, My rpm dro is inaccurate and varies greatly.
I know mach x pulsing driver was updated for faster bus computers,
Did it cause lower bus speed computers to have inaccurate rpm or inconsistency even
with single pules disk?
Even thou I have a mill, I'm interested in threading using both a 60 deg lathe
cutter in a holder mounted on the table as well as mill threading and turning
using 4 axis control.
as in these videos as examples
http://www.youtube.com/watch?v=gUw9XKjMfUg (http://www.youtube.com/watch?v=gUw9XKjMfUg)
http://www.youtube.com/watch?v=yU_SeEvSsqE (http://www.youtube.com/watch?v=yU_SeEvSsqE)
http://www.youtube.com/watch?v=pQ83XRgRCyg (http://www.youtube.com/watch?v=pQ83XRgRCyg)
hope not to get in trouble as the links relate to my post.
Dell Dimension 8300
Intel Pentium 4 3.20Ghz Hyper Thread
1 GB Ram
Windows XP Pro 5.1.2600 Service Pack 3
Nvidia Geforce FX5200 128MB 1024x768x60Hz
Mach 3
Licensed Mach 3
Version R3.042.04
Mach x Pulsing Engines 4-11-2010
Version 5.50.0.0
Pulse Frequency 24998 rock steady
Time in Int. 4.2 to 5.2
PWM Base +140
Cnc Machine
MaxNc 10 Open Loop 2005
Omron EE-SX 872 Optical Interrupter
Sensor has electronic circuit signal conditioning
Direct connect to printer port pin 15 port 1 (no bob, 5volt + and ground from
MaxNc stepper control board, connections are verified good.)
5.09 volts on pin 15 active pulse window on printer port buss
.025 volts on pin 15 no pulse window on printer port buss
clean o scope signal
Setting
Index De bounce = 0
Index pin 15 port 1 enabled
TurnDiags - 1.00.1 NOT enabled
I would like to have the spindle rpm work right so the feed will
follow with rpm, If it's possible.
Thank you.
Richard
kb7cga
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Two things, first for threading lathe style you will need to have Use Spindle Feedback in Sync chosen, also you may need spindle speed averaging chosen for a steady RPM to actually show in Mach, all depends on your drive setup.
These options are from Config menu then Ports and Pins then Spindle Setup page.
Hood
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Hello Hood
Spindle Feedback in Sync and spindle speed averaging are chosen.
m3 on a S500 I get a rpm of 5800 to 5990, not good in cnc land :(
I should be more stable and at the correct rpm, that is more than 5300 rpm off .
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Just looked at the vids, the last one shows thread milling, you dont even need spindle feedback for that as it just needs coordinated XYZ movement.
I will see if I can find a link to Simpsons machine, think you will like that :)
Hood
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You didnt have them chosen in the xml attached, are you meaning you have just tried them and its no different?
Try a small amount of index debounce then, 1 or 2 and see if that helps.
Hood
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I do intend to thread mill soon when i can get the cutters, but for now, I was going to
use a 60 deg lathe cutter in a vice on the table like in the vid link I sent.
I just tried them with no difference. trying the debounce now.
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just tried a debounce change, here are the results.
start with m3 s500
bebounce 0 =rpm 5800 to 5990
bebounce 1 =rpm 117 steady
bebounce 2 =rpm 117 steady
bebounce 3 =rpm 117 steady
does the debounce interval affect any thing?
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The steady 117RPM, is that the correct speed?
Debounce Interval is for all other inputs other than Index.
Heres the vid I was talking about earlier.
http://www.youtube.com/watch?v=NzY-OqckqpI&feature=autoplay&list=UL1xv603HHs3U&index=9&playnext=1
Hood
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Cool video.
m3 s500 should give rpm of 500.
I don't have the option of mounting lathe tools on the spindle head as the stacked bearings
are in the way. cool move thou.
have a look at the second vid like in my post as it the same setup as I'm trying.
Richard
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Yes, have seen that before, also quite a few other similar ones floating around.
Ok so the Index debounce is obviously not helping, not sure what else to suggest as its not normally a problem getting a speed reading.
What dia of slotted pulley do you have and how wide is the slot?
Hood
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Just noticed you said 42.04 version of Mach, try the latest as I am not sure if that version had the threading fixes.
Hood
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Disregard my last post, just realised yu will be meaning 042.040.
Driver version sounds old though, will just go check
Hood
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No driver version is the latest so you should be fine.
Hood
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2" single pulse disk with a slot with of .2"
Mach3 R3.042.040 is the Lockdown version I'm using.
Mach3 R3.043.022 is still in Development and was not sure if i should try it until this
problem was resolved.
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No that version is fine, you had said 3.042.04 and I was thinking that was old but then realised after I posted you were meaning 3.042.040.
Dont really remember what the specs in the manual for spindle pulley and slot is but when I used the PP I always had about 100mm dia and 10mm slot so wondering if that could be your problem?
Did this work previously with an older version or have you just set it up?
Hood
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I just set it up for the first time.
has any one had problems with the new changes or had to revert to a older
version?
should this work fine with my computer? (specs in first post.)
Did the new changes after 3.042.031 ( 032 to now ) knock out some
motherboards from using the index rpm feature?
I'm Stumped as to why it's not working right.
Richard
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No should be working fine, cant recall anyone having issues other than when they had Index Debounce too high. Just wondering if its anything to do with MaxCL mode as I know pins get hard set in Mach when using the Max NC mode so may be the same for CL.
Hood
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It does seem the pins are set for MaxCL mode as well, it says pin 15 has nothing assigned but wondering if that means it cant be used or not. Afraid I know nothing of the MaxCL machines :(
Hood
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The spindle on the MaxNc uses pwm to switch the spindle motor on an off as a variable speed control.
By switching a electronic rely vary fast, you can have mach 3 control the speed of the spindle.
Could this be interfering with the rpm counts?
Just took mach out of MaxNc mode, tried it.
results: no change
put mach back in MaxNc mode.
On the mill control board, pin 15 is not connected to anything or any circuit traces.
It's a unused pin.
Any Ideas hood?
Richard
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No, afraid I dont have any ideas , only thing I can think of is going direct to the port, if possible, with the index rather than going through any boards (presuming you have some sort of BOB/Interface)
Other thing is the slotted pulley size as mentioned earlier but think that would make the spindle speed show slower if the pulse wasnt seen correctly due to the pulley/slot being too small.
Hood
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The output of the sensor is going strait to the printer port, no bob, no traces to anything on the
controller board, just a open pin #15 on the rs232 strait through cable, and yes I tested the cable
just in case ( I have been dumb before and grabbed a bad cable ??? by accident. )
In the pulley configure I did make sure the ratio was 1:1 as the sensor directly reads the spindle.
slot size, on a 2" disk ,I would think that .2" wide would have been more than enough.
I can try another disk if you think it would help. I once saw the calculations some where
but making a new disk will only take a few minutes.
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I dont know if it would make a difference, if its easy enough to do then you might as well try I suppose.
Just wondering if you can disable the PWM in Mach, call a M3 and spin the spindle by some other means, maybe even by hand to see if the relay switching is the problem.
Hood