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Author Topic: Threading reboot  (Read 2860 times)

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Threading reboot
« on: March 24, 2016, 09:02:44 PM »
Nothing has worked so far so a fresh start.

1.  To get threading to work I need to get a stable readout of actual spindle speed into Mach3.  Is this correct?  Or does the input signal have to be of a certain form? (Absolutly no luck getting a stable readout using two different proximity sensors.)

2.  If I figure out how to do the slotted disk, optical readout approach to get spindle speed into Mach3 do I have to worry about noise from the VFD or other source corrupting the signal? Special wiring needed etc?

3.  Once I can get a stable spindle readout into Mach3 then the hardware part is finished and from there on it is pounding away at Mach3, OR do I need more index input signals? I am operating under the assumption that if I can get a stable read out of spindle speed all my hardware issues are behind me, agreed?

Thanks.

Offline RICH

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Re: Threading reboot
« Reply #1 on: March 25, 2016, 07:32:06 AM »
Yes you need a table stable input for the index signal and the more stable the better, but at least within in the 1 rpm range.. Noise can be a problem and would suggest shielded wire as it is easier to keep noise out then to try and remove it. Will just have to try and see if there is a noise problem.
Slotted disc works fine but I use a Hall affect sensor as it is easier to mount ( just be aware that some are reed sensors and have response limits).
Currently only index input is used in ports and pin's.

Hardware can be a problem if your axis is not repeatable, has backlash, or is not accurate.

RICH
Re: Threading reboot
« Reply #2 on: March 25, 2016, 05:51:30 PM »
So, carrying on.  The proximity sensor will give me wildly varying RPM numbers varying in a random pattern from actual RPM to 1/2, 1/3, 1/4 etc of actual RPM, but never a readout greater than actual RPM.

Then I tried a Hall sensor.  Again wildly varying RPM but of no discernible pattern. Running at 300 RPM I get readings varying from 1 to 30,000. This time a shielded cable.

I have played around with debounce levels, varying spacing for the sensor, etc but as far as I can tell nothing has made any difference in the readout pattern.

Does this sound like a hardware problem or a problem in my Mach3 settings?  And if the problem might be in the settings, where should I start to look? 

Thanks.
Re: Threading reboot
« Reply #3 on: March 25, 2016, 06:32:45 PM »
It could be your hardware but you haven't given details of what it is so everyone is guessing ;-)
Re: Threading reboot
« Reply #4 on: March 25, 2016, 06:33:37 PM »
Start by giving full details of your system, the less guessing the better!
Re: Threading reboot
« Reply #5 on: March 25, 2016, 07:08:56 PM »
The proximity sensor I am using is from Automation Direct http://www.automationdirect.com/adc/Shopping/Catalog/Sensors_-z-_Encoders/Inductive_Proximity_Sensors_-z-_Proximity_Switches/8mm_Round_Industrial_Automation/Standard_Sensing_Distance_(8mm)/AE1-AN-1A
and is one that was recommended by one of the knowledgeable people on Hobby Machinist (Dawson).  

The Hall sensor is one that came with a MachTach kit I ordered and all his other bits and pieces have worked flawlessly, but that kit only gives RPM readout, it does not feed it into Mach3. With the MachTach I used an optical sensor and since a Hall sensor came with the kit I put it to use to get spindle speed readout into Mach3.  This setup allows me to compare the accurate MachTach readout with what I am getting in Mach3.

Spindle speed is controlled by hand directly at the VFD, and spindle speed is not controlled through Mach3.  I am just trying to get an RPM readout into Mach3, not to control spindle speed.

Hope this helps.

Mach3 is version R3.043.066

Offline mc

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Re: Threading reboot
« Reply #6 on: March 25, 2016, 07:43:02 PM »
Are you using a parallel port, or an external motion controller?
Re: Threading reboot
« Reply #7 on: March 25, 2016, 07:51:43 PM »
My system is a parallel port from my computer to a Camtronics controller which is based on a Gecko board.  The spindle sensor signal goes into the Camtronics unit.

http://camtronics-cnc.com/stepper-components.asp

Offline RICH

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Re: Threading reboot
« Reply #8 on: March 25, 2016, 07:58:57 PM »
- I can't speak / have not used Ver.066 but it is known to be problematic.
  V 062 is in use here.
 
- For threading one would use the index, but if you have a VFD then you set the rpm manualy
  but MAch will need to read the rpm based on the index input. It needs that input to know when   to start the next threadng pass. Just thought to mention this.

- Are you using an otpical sensor along with a slotted disc? A cd rom painted black with a
  slot work fine. Can just put black tape on it to adjust the slot width if so desired.
  no harm on the slaot being wider than calculated.

- I use a small ( 1/8" diamater ) rare earth magnet along with my Hall sensor. Works like a   charm!. Radio Shack used to carry them.

RICH

Offline RICH

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Re: Threading reboot
« Reply #9 on: March 25, 2016, 08:04:06 PM »
Where does the wire from the spindle sensor go to inside the Camtronics  box. I would think that it would then go to an input pin of the PP cable connector.

RICH
« Last Edit: March 25, 2016, 08:18:05 PM by RICH »