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MACH3 MachTurn not picking up "Index" on mini lathe
« on: June 12, 2022, 09:03:58 PM »
I recently purchased a Harbor Freight Mini Lathe that someone converted and I am wanting to get a spindle index/tach set up to cut threads, etc.
It is using Mach3 with a Gecko 540 running through a UC100.   
I wired in a C3 Index pulse card and wired it in according to the diagram in the description. Only to find that the UC100 doesn't support the Index function in Mach3 Turn.   
Is there a possible work around?  The computer that I am running doesn't have a DB25/parallel port to plug into directly with a cable. 
Any suggestions would be appreciated.  Thank you in advance.
Re: MACH3 MachTurn not picking up "Index" on mini lathe
« Reply #1 on: June 12, 2022, 11:25:26 PM »
Hi,
if I'm not mistaken none of the CNCDrive motion control boards (UC100, UC300,UC400) support single point lathe threading.
In order to synchronise the start of the thread the motion controller must do it. The communication delays (controller to Mach, Mach makes up it mind, Mach to controller plus buffer delay)
are such that Mach is not fast enough to synchronise the start of a thread, whereas the motion controller is.

Mach's parallel port can do it, if somewhat less precise. An Ethernet Smoothstepper, a PoKeys 57CNC, a Vital Systems Hicon or a CSMIO can all do lathe threading. Of them I use
an Ethernet SmoothStepper, although not for lathe threading.

Craig
'I enjoy sex at 73.....I live at 71 so its not too far to walk.'
Re: MACH3 MachTurn not picking up "Index" on mini lathe
« Reply #2 on: June 13, 2022, 01:40:39 AM »
When I upgraded my shop with a new PC I chose the UC100 for both lathe and mill (separate units).  I asked a lot of questions of CNCdrive including about UC100 threading support and got this reply.

"3.) The UC100 works with the UCCNC, Mach3 and Mach4. The UC100 does
> not support thread cutting with Mach4. It supports thread cutting with
> index sensor with Mach3 and it supports syncronous thread cutting with
> encoder feedback with the UCCNC."

I haven't yet tried threading but every other function operates and it certainly picks up the index pulse from the opto on my spindle as it correctly displays spindle speed.  Does yours display speed?  If not there is probably an issue with the pulse signal.   It could be that the polarity is set wrong or the debounce setting is wrong (too large).  If you have an opto sensor debounce shouldn't be needed.  Have you looked at the signal on the diagnostics screen to check you can see the state of the input change when you slowly rotate the spindle by hand?
« Last Edit: June 13, 2022, 01:46:06 AM by JohnHaine »
Re: MACH3 MachTurn not picking up "Index" on mini lathe
« Reply #3 on: June 13, 2022, 02:11:02 AM »
Hi,

Quote
"3.) The UC100 works with the UCCNC, Mach3 and Mach4. The UC100 does
> not support thread cutting with Mach4. It supports thread cutting with
> index sensor with Mach3 and it supports syncronous thread cutting with
> encoder feedback with the UCCNC."

Kool, there was a period of some years where CNCDrive products did not support lathe threading at all (Mach3/4 or UCCCNC).
Clearly this situation has improved somewhat.

Given that the UC100 does support threading then John's guess about the UC100/BoB not recognising the pulse input is very likely correct.
If you can get the UC100 to signal Mach the exact spindle speed then lathe threading probably follows easily.

Craig
'I enjoy sex at 73.....I live at 71 so its not too far to walk.'
Re: MACH3 MachTurn not picking up "Index" on mini lathe
« Reply #4 on: June 13, 2022, 08:32:26 AM »
When I upgraded my shop with a new PC I chose the UC100 for both lathe and mill (separate units).  I asked a lot of questions of CNCdrive including about UC100 threading support and got this reply.

"3.) The UC100 works with the UCCNC, Mach3 and Mach4. The UC100 does
> not support thread cutting with Mach4. It supports thread cutting with
> index sensor with Mach3 and it supports syncronous thread cutting with
> encoder feedback with the UCCNC."

I haven't yet tried threading but every other function operates and it certainly picks up the index pulse from the opto on my spindle as it correctly displays spindle speed.  Does yours display speed?  If not there is probably an issue with the pulse signal.   It could be that the polarity is set wrong or the debounce setting is wrong (too large).  If you have an opto sensor debounce shouldn't be needed.  Have you looked at the signal on the diagnostics screen to check you can see the state of the input change when you slowly rotate the spindle by hand?

The machine didn't come with a pulse card or pick up so I purchased a C3 Index Pulse card with pick up from CNC4PC.  The card has an LED that blinks when the slot passes through the pick up as it is supposed to.  My slot is a little wider than the Mach manual instructed.  I have the card switched for active low and OC pick up.  I have the index active in my config and set for active low.  I don't recall what my debounce is set at will have to look at that later (any suggestions for a range?)  I have checked the diagnostic screen and my index light doesn't "light" but the card still does. 

I have had a few people tell me the UC100 doesn't support index in MachTurn but I want to make sure that I am not giving up too soon.  I am trying to avoid switching to a PC that has a parallel port.  Not that I have a problem with that, I have my desktop mill running that with no problems but the idea of the time to do the swap.

All input is appreciated, Thanks for the help.
Re: MACH3 MachTurn not picking up "Index" on mini lathe
« Reply #5 on: June 13, 2022, 12:05:44 PM »
Well, I can confirm that the UC100 should see the index pulse because that is how the spindle speed is measured, and my Mach3 Turn instance does show the correct spindle speed!

Clearly the sensor is picking up the slot which is good.  (There is just one slot, right?)  However Mach3 isn't seeing it.  You have set the card for Open Collector output, does it have a pull-up?  You could select TTL output if it doesn't.  Try active high, as the effective pulse length can be short or long depending on how the pulse is interpreted.  For debounce, as I said you shouldn't really need it with an opto so set very low.
Re: MACH3 MachTurn not picking up "Index" on mini lathe
« Reply #6 on: June 13, 2022, 12:31:55 PM »
By the way there is a very good support forum for CNCDrive (who make the UC100) here:

http://www.forum.cncdrive.com/index.php

Re: MACH3 MachTurn not picking up "Index" on mini lathe
« Reply #7 on: June 13, 2022, 01:48:01 PM »
Well, I can confirm that the UC100 should see the index pulse because that is how the spindle speed is measured, and my Mach3 Turn instance does show the correct spindle speed!

Clearly the sensor is picking up the slot which is good.  (There is just one slot, right?)  However Mach3 isn't seeing it.  You have set the card for Open Collector output, does it have a pull-up?  You could select TTL output if it doesn't.  Try active high, as the effective pulse length can be short or long depending on how the pulse is interpreted.  For debounce, as I said you shouldn't really need it with an opto so set very low.

Thank you for the input.  Yes, there is just one slot.  I will try the other settings to see if anything bares fruit.  Thank you for the link to the forum.  I will look into that. 
Re: MACH3 MachTurn not picking up "Index" on mini lathe
« Reply #8 on: June 18, 2022, 12:09:20 PM »
Another data point.  I just for the first time tried Mach3 threading using the standard wizard on my lathe and the UC100 motion controller.  Not actually cutting metal but just checking it behaved as expected - it did!  So as expected the UC100 does support Mach3 threading using a single index pulse.
Re: MACH3 MachTurn not picking up "Index" on mini lathe
« Reply #9 on: June 19, 2022, 04:05:34 PM »
I was "playing" with the lathe this morning and didn't get anywhere.  I attempted Active Low and didn't get anything in the Diagnostic Screen but if I "de-activated" Active Low the Index light would stay on permanently in the diagnostic screen.

I don't have a pull up in any connection.  Where would I need to install the resistor?   

I tried all combinations of active low/high and OC/TTL on the card and via Mach 3.  I moved the input from the card from input 1 on the Gecko (DB25 PIN 10) to input 4 (DB25 PIN 13) and made the adjustments in the configuration and didn't get anywhere.  I even connected a computer via parallel port and and clone of my Mach3 and got the same results.

I have multiple paths to pursue but not sure where to start.  1) In the wiring diagram from CNC4PC for the C3 to the Gecko, it doesn't show the ground terminal in the output block connected.  I assumed that it grounded through the power supply in the other connections.  Should I connect that ground to the Gecko or 5V power supply or ???? 2) The same diagram does not show a pull up resistor, would I put that into the pick up input between the card and the Gecko? What sized and type of resistor am I looking for?  3) What kind of signal should I be looking for out of the card?  Should I be looking for a 5V "spike" when the slot crosses the pick up? 4) I don't know when the software for the UC100 was installed.  It came with the machine when I bought it.  Should I download the most recent?

I greatly appreciate all of your input.  I am beginning to think that the core of my issue is stemming from the way I have the card wired.  Any diagrams or suggestions, would be welcomed and appreciated.

Thanks in advance.