MACH3 and MPG Pendant

This forum is dedicated to those Hobbyists Interested in CNC machining in their home shops. (Digital Read Outs are also topical, as is CAD/CAM as it relates to CNC)

Moderator: Harold_V

User avatar
ctwo
Posts: 2797
Joined: Tue Mar 27, 2012 12:37 pm
Location: Silly Cone Valley

Re: MACH3 and MPG Pendant

Post by ctwo » Wed Jul 15, 2020 3:08 pm

There would have to be something to sink that current on the parallel port IC. There are current limiting resistors between the logic transceiver and the port, which should limit to ~100mA. The transceiver chips are rated to 50mA max output current, and I believe there are also resistors inline on the parallel port IC inputs, and a diode on the supply input to the BoB. I'd think 100mA would take out the transceiver and parallel IC. 100mA would explain the toasty resistors though, but why?
Standards are so important that everyone must have their own...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...

User avatar
ctwo
Posts: 2797
Joined: Tue Mar 27, 2012 12:37 pm
Location: Silly Cone Valley

Re: MACH3 and MPG Pendant

Post by ctwo » Wed Jul 15, 2020 5:47 pm

Well, now I've ordered a MP9715P-2 card with the nv9805cv chip and when looking for drivers, Google found the same driver that I installed for the card that I already have. It's not the same card, but now I'll have to check the chip. Might be bummed if it's the same... Maybe I can just bump up the IO resistor values on the BoB...
Standards are so important that everyone must have their own...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...

hanermo
Posts: 49
Joined: Tue Oct 01, 2013 5:47 am

Re: MACH3 and MPG Pendant

Post by hanermo » Wed Jul 15, 2020 8:09 pm

My €0.03..
1.
the pp pendants are basically a waste of time.

Because the signals are polled at low speed, 25 kHz, rely on catching state changes, and often have hw issues as you have seen, they have nothing to do in terms of functionality with real pendants.

Ex.
A PP MPG wheel, will have high and variable latency, for each pulse.
So it sometimes works ok, sometimes weak, and you have a "mushy" slow control path.

2.
GOOD hw controllers can deliver exceptional MPG control.
Sometimes for little money.
Pokeys (e) is one such piece of kit.
It delivers exceptional hw-based mpg and jogging functions, (+probe, homing, encodders etc).
Excellent value for money.
I use it on my 100k€ VMC, scratch built.
For less than 200€, very good value.

User avatar
ctwo
Posts: 2797
Joined: Tue Mar 27, 2012 12:37 pm
Location: Silly Cone Valley

Re: MACH3 and MPG Pendant

Post by ctwo » Wed Jul 15, 2020 10:07 pm

So you're saying the $100 wireless MPGs on ebay would be ng either?

Pokey has the same pendant that I have, without the extra E-stop and other button. PP would seem to be a hardware interface whereas Ethernet and USB would be software.

Is the MPG inputs handled in the controller directly and then passed to the control SW? (MPG->controller->step drivers and MACH3) or (MPG->controller->MACH3->step drivers) i.e., can drive the machine without the PC on.

I guess PoKeys57CNC would be all I needed. I think my pendant is good, feels good and all I really need. I can add buttons if I need, looks like there are extra wires in the cord.
Hey, does that mean I could use the PC in my house from a network connection to the controller?

There is a US supplier. Hmmm... more money is always the solution.
Standards are so important that everyone must have their own...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...

User avatar
ctwo
Posts: 2797
Joined: Tue Mar 27, 2012 12:37 pm
Location: Silly Cone Valley

Re: MACH3 and MPG Pendant

Post by ctwo » Mon Jul 20, 2020 7:48 pm

A different PCI to Parallel port card did not change the behavior, which I am getting that in order for pins 2-9 to be used as input pins, you need an EPP compatible card, which both cards should be. Remember, my original card worked a couple times.

This isn't an issue with the BoB as setting MACH3 to use pins 2-9 as inputs sets the pins high, and I can see the LED indicators in MACH3 all light up, and shorting the port pins with a resistor does not make them go off like they should. Pins 10-13 + 15 do go off so the card is configured correctly. It may be a driver issue or software issue. I tried finding another driver and none will install.

That's all I got for this.
Standards are so important that everyone must have their own...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...

User avatar
ctwo
Posts: 2797
Joined: Tue Mar 27, 2012 12:37 pm
Location: Silly Cone Valley

Re: MACH3 and MPG Pendant

Post by ctwo » Mon Jul 20, 2020 10:54 pm

well, one more. I swapped ports and tested the MB port inputs in both ECP and EPP mode. ECP will light up the pins correctly, but it still does not toggle off when grounded.

I've been reading about some issues with the Pokey's interface. Of course you're going to have that. Looking at UCCNC or Pokeys, or even LinuxCNC with parallel ports.
Standards are so important that everyone must have their own...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...

User avatar
ctwo
Posts: 2797
Joined: Tue Mar 27, 2012 12:37 pm
Location: Silly Cone Valley

Re: MACH3 and MPG Pendant

Post by ctwo » Sun Aug 02, 2020 11:05 am

I stumbled on a new open box PoKeys57CNC on ebay, so that is on it's way. I don't like the way the pendant is wired because I will have make my own interface cable to swap some of the wires.

Does anyone know what kind of plug is for the e-stop? 4-pin header with adjacent pins offset; or maybe it's an 8-pin dual row header with 4 pins removed?
Standards are so important that everyone must have their own...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...

Post Reply