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Indexing Problem with R.3.042.032
« on: November 10, 2009, 06:42:31 AM »
Hi

Is anyone else having problems with indexing in the latest release.

I have been running R.3.042.020 for some months, using a single slot index disc with a good stable RPM indication.
I upgraded to R.3.042.031. and experienced the following problems:

Under automatic spindle control (Digispeed controller and VFD) RPM is showing as a negative eg. -218 RPM at a true speed of 500 RPM. Under manual spindle control (potentiometer and VFD) RPM indication is 0 RPM at all times.

I changed back to R.3.042.020 and normal speed indication was restored in both auto and manual spindle control. I then upgraded to R.3.042.032 and had the same problems as above.

If I run the Turn Diagnostics plugin, I am getting a Rotation Speed Realtime of 501 RPM in both cases and an Application End RPM of minus 218 RPM under auto spindle control or 0 RPM under manual spindle control.

I have now reverted again to R.3.042.020 and speed indication is normal again in both auto and manual.

Just wondering if anyone else is having problems.

Peter

Offline RICH

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Re: Indexing Problem with R.3.042.032
« Reply #1 on: November 10, 2009, 07:10:05 AM »
Try changing your index debounce, i use a value of 10.
Have not tried the latest versions yet / still using .030.
RICH
Re: Indexing Problem with R.3.042.032
« Reply #2 on: November 10, 2009, 08:00:43 AM »
Hi Rich

Thanks for your reply.

I tried changing the index debounce. I usually have mine set at 2, but I tried it up to 200 at various stages without any change.

I loaded version .030 and this time I got the same RPM in both auto and manual spindle control. That is at 500 RPM it is indicating minus 218 RPM in both auto and manual.

The 500 is just an arbitary figure. For example at a commanded speed of 200 the indication is minus 88 and at 1000 the indication is minus 433. At the commanded speed, the actual speed measured with a tacho is within 1 or 2 RPM at mid range (500) and within 5 RPM at 1000.

When I first upgraded to version .031 I tried to run a spindle calibration but because it was showing minus, it wasn't even registering on the graph, so I aborted.

I am now back with version .020 and it is normal again.

Peter

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Re: Indexing Problem with R.3.042.032
« Reply #3 on: November 10, 2009, 09:27:39 AM »
Maybe someone else will chime in and shed some more light on this.
RICH  ???
Re: Indexing Problem with R.3.042.032
« Reply #4 on: November 12, 2009, 06:19:45 PM »
Hi

Can anyone advise on the relationship between Rotation Speed Realtime and Application End RPM in Turn Diagnostics. The Realtime RPM is shown as a stable and true representation of the actual spindle speed, which suggests to me that Mach is receiving a good signal from the indexer.

The Application End RPM is displaying a negative value and it is this figure which is showing up in the True Speed DRO.

Under R.3.042.020 both realtime and application end RPM are the same.

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Re: Indexing Problem with R.3.042.032
« Reply #5 on: November 12, 2009, 07:22:09 PM »
 The new code is based on reading of your rpm. What are the specs on your tach? I am going to guess that it is
-+ some percent +- 1 RPM.... I believe that the turn diagnostics real time is more accurate than your tach ( from
some tests we did as check / and you don't have the specialty equipment to do it).

Now the DRO, may say 500, stay there or go back and forth some, say 500,501,500....... Even if the DRO  stays at say 500, that dosn't mean your rpm isn't changing, it does, maybe small, but it does. Now you will see those changes  in the rotation speed real time box.

BTW, don't forget that what is being measured is via the index pulse sensor. A sensor can be triggering slightly differently even if the signal is conditioned. I will leave that kiind of stuff to the electronics folks.

So the rpm that will be applied to the threading cycle will be the appplication end rpm. You will see that after the first  pass that it is a different rpm, since during the first pass Mach used rpm info from it to plan the next  pass and adjusts the feedrate accordingly. Now small but very important.  

SO you have a real time rpm which is varing and an application end rpm used for the actual threading.
By the way i suggest  spindle speed averaging in config.


Now as far as your negative display....maybe someone else can chime in and explain.

RICH

BTW,what is important is the way your motor, belt/ gearing, the index pulse act as a "system" so don't get hung up on some finite element of them because , again extremely difficult to measure  and even if you can, you probably may have not have a  way of improving it .

Forgot to mention that i am still at version .030.
« Last Edit: November 12, 2009, 07:32:58 PM by RICH »
Re: Indexing Problem with R.3.042.032
« Reply #6 on: November 13, 2009, 08:00:46 AM »
Rich, thanks for your reply. I accept what you say about the tacho and the RPM does indeed fluctuate by small amounts, around 1 RPM in the realtime speed box. As I understand it, you are saying that the realtime speed is conditioned into the application end RPM for threading, which makes sense.

I guess something in my setup is interfering with the process of conditioning the realtime speed in the latest software releases.

Thanks for the explanation.

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Re: Indexing Problem with R.3.042.032
« Reply #7 on: November 13, 2009, 06:36:54 PM »
meptune,
I just installed ver .032...........
NO index and and no rpm on my end at all. Thus threading broke!
RICH
Re: Indexing Problem with R.3.042.032
« Reply #8 on: November 13, 2009, 07:44:27 PM »
Rich

It would appear to probably be the same problem, just showing itself slightly differently. But there again, .030 was working on your system but I also had problems with that version.

Just for the record, I have so far tried manually uninstalling the driver, completely unistalling mach from the computer, then reinstalling with the standard mach3 turn profile configured with just enough to get the motors turning and the index enabled. The problem is the same as with my normal turn profile.

BTW, I didn't previously mention but my system is connected via PP.

Peter

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Re: Indexing Problem with R.3.042.032
« Reply #9 on: November 13, 2009, 09:38:31 PM »
Peter,
Art and Brian are aware of the problem, whatever it is, so hang in there until they take a look. 
No use trying to guess. I have been posting anything i find in the "Problems Threading On The Lathe" so you may want to follow that thread.
Can be frustrating at times.  ;)
RICH