Messages

1

PoKeys / Re: Beware Pokeys 57E is NOT a stand alone BOB

« on: June 21, 2016, 03:50:10 PM »

"if my Pokeys starts cooperating"

So, it has not been all smooth sailing for you either!  That's quite an undertaking.  I used to do stuff like that back when I was younger, but now that I'm 65 I hate giving up a single minute more than what is needed to get the job done.

I did get the axes all going this morning, and that was with the original optos on the motor controller boards.  It was just a matter of getting the internal LED correctly biased to limit the input current, which took a little more time than I would have liked.  I have to admit the potential of the 57E is phenomenal at the price, but my original topic heading holds true.  It is NOT a stand alone BOB.

Thanks for your encouragement.

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PoKeys / Re: Beware Pokeys 57E is NOT a stand alone BOB

« on: June 21, 2016, 09:18:30 AM »

Oh, I see I looked at the Absolute Maximum ratings when I got the 50 mA.  The graph in figure 12 does show that 4 mA will turn it on.  I'll get a few of them ordered.

That's quite a breakout board you turned the 57E into!  Can it be purchased somewhere or did you build it yourself?

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PoKeys / Re: Beware Pokeys 57E is NOT a stand alone BOB

« on: June 20, 2016, 11:26:55 PM »

I've gotten some help from support but I still don't have everything working yet.  The data sheet for the EL817 opto mentioned above says it has a 50 mA input current.  How can that work on the 4 mA output current from the 57E?

I ordered a few LDA111 and they worked on the enable and direction signals, but not on the speed pulses.  Turns out the turn off time is way too slow.  The 4 micro second turn on and off time of the EL817 should be fine, but the input current is way too high.  I'm searching now for something that will work for the speed signal.

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PoKeys / Re: Beware Pokeys 57E is NOT a stand alone BOB

« on: June 13, 2016, 01:26:16 AM »

I sent Matevz an email with several questions last Tuesday and have not received a response.

I have most of the 57E signals working correctly and verified with an oscilloscope, it's just that the pins won't drive the loads.  The only signal I have not gotten the 57E to output is the PWM speed signal.  I was thinking to use pin 17 if I could figure out which IO to assign to it.  What is the Mach3 PWM signal called?  One might not even need a PWM output from the 57E.  If Mach puts out a high/low of the correct duty cycle for the speed signal, it could simply be mapped to any output pin and that pin would put out the corresponding duty cycle.  The problem is, I can't identify the Mach speed variable.  I can find no documentation or posts that tell what it is called or what DRO number it is or whatever.

The other Mach variable I can't identify is the tach signal input (and probably the pulses per rev setting) that displays in the spindle motor RPM box.  Maybe it's simply not in the 57E list and the device is not programmed to accept a tach signal.

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PoKeys / Beware Pokeys 57E is NOT a stand alone BOB

« on: June 12, 2016, 09:01:04 PM »

I bought a simple Bridgeport BOSS4 CNC with an old CNC4 Centroid upgrade on it back in September, 2015.  I analyzed the Centroid control system and ordered a Xulifeng BOB from China.  The BOB works great and for $150 plus an old XP computer I had sitting in the closet, I was up and running with Mach3.  The only thing the Xulifeng wouldn't do was send the quadrature encoder signals to Mach3 for position readout.  I realize Mach3 is not closed loop, but it would be good to be able to compare the number of steps requested by Mach3 to that actual number of steps counted off by the encoders.

Enter Pokeys 57E.  Everything I read about it said it had an onboard 3 axis pulse generator and could handle all the Mach3 IO including MANY quadrature encoders.  Sounded like just what I wanted, so I ordered one.  What they DON'T tell you is that the 57E (without the compatible 8 channel CNC add on) won't drive much in the way of loads.  It won't even toggle the opto isolators on the stepper drive cards.  I've ordered opto isolators that will operate on a 1 milliamp input, so hopefully those drop in replacement optos will work.  I'll let folks know when I get them and get a set soldered onto one of the stepper cards.

Next, I tried to get the spindle motor going.  I'm running it with a TECO L150 VFD.  All I needed was a low output for FWD, another for REV and a 10 volt PWM for the speed command.  The Xulifeng had the PWM mapped to a dedicated output which works perfectly and a couple of output pins mapped to Mach2 Output #1 and Output #2 did the trick.  Well, the 57E can map Output #1 and Output #2 to the Fwd and Rev inputs on the VFD, but they won't drive it.  It turns out that whatever drives those pins has to provide a solid ground signal to turn the motor on but that signal must go to a high impedence to turn the motor off.  The 57E supplied enough low drive current to keep the motor on not only in the low state, but also in the high state, or even if you connect the VFD pins directly to the Pokeys 3.3V or 5V supplys!  Those voltages are much lower than the 22V the VFD pulls up to, so enough current flows, even from a 10 volt input, to keep the FWD or REV pins active.  Well great.  Now I'm going to have to build circuitry to make the 57E drive those two pins.

Now for the PWM speed signal.  The 57E has 6 PWM outputs, so surely it will be easy to map the Mach3 PWM speed signal to one of those, right?  I mean, I realize I'm going to have to build circuitry to boost the 3.3 volt PWM from the 57E to a 10V PWM, but hey, I'm used to that by now.  Well guess what?  You Know that big list of IO that comes up when you go to map a Mach3 IO to a 57E pin?  NOWHERE in the 57E manual or the Pulse Engine manual does it give descriptions of what all those choosable IO functions do or how to use them.  I can't find an output that I can identify as the Mach3 PWM output.  Nor can I find an input that looks like it might be a pulse input for my 4 pulses per revolution tachometer on my mill spindle (on the Xulifeng, that signal goes to a dedicated input and it displays the tach signal in the spindle motor RPM box in Mach, just like it is supposed to do).

Well, that is as far as I've gotten to date, but if the other signals I need to run the mill all have to have driver circuits built for them, it just isn't going to be worth it.  Is anyone else having a similar fun time with the 57E?

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PoKeys / Pokeys 57E mapping to Mach3 PWM

« on: June 11, 2016, 02:13:30 PM »

How do I send the PWM signal from Mach3 to Pokeys 57E?  I can scale one of the 57E PWM outputs to 10V easily enough, but I can't figure out how to get the Mach speed signal into the 57E.

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General Mach Discussion / Re: Can't generate G code for this simple dxf...

« on: March 20, 2016, 10:07:12 PM »

Is there a better converter that will do ellipses for a retired guy on a fixed income?

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General Mach Discussion / Re: Can't generate G code for this simple dxf...

« on: March 20, 2016, 09:49:14 PM »

It saves as an Autocad dxf.  I can save in Autocad 2010, 2007, 2004, 2000 or R12.  I think the problem is the ellipses.  I tried saving a dxf of just one of the three ellipses and couldn't get it to translate.  Probably too many points for the converters to handle.  I can approximate the ellipses pretty closely with circular arcs of the correct size chained together, but what a PITA of a way to do this.

Hmmmm.  You got me thinking.  I saved it out as an R12 dxf and it converted.  It looks like about 130 point straight line approximation of the ellipse, but that is close enough for my purposes.  I can get it from here.  Thanks.

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General Mach Discussion / Can't generate G code for this simple dxf...

« on: March 20, 2016, 07:11:29 PM »

When I first learned about Mach 3 I was excited.  It looked like I would be able to put my experience with computers and programming to use, so I put all this time and effort into converting this old Bridgeport CNC to Mach 3 and I can't manage to convert the simple attached dxf figure (which I drew and generated with Inventor in just a few minutes) to G code for engraving onto a surface.  LazyCam won't do it and the Ace Converter program I downloaded won't do it.  The whole idea behind becoming Mach 3 capable was so I wouldn't have to key in G code a line at a time.  What is the solution?

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General Mach Discussion / Xulifeng responds!

« on: November 28, 2015, 11:19:38 AM »

I emailed Xories at ebay (from whom I bought the Xulifeng BOB) and directly at EBAY@XORIES.COM and they responded.  After three exchanges I got them to understand my question.  They confirmed that their board does not support looking at the encoder inputs on the Settings screen in Mach3.  I understood from these forums that Mach3 does not support closed loop operation using encoders with steppers, but it would have been nice to be able to look at encoder position if there was a cutting error.

Ron