Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: kak on June 27, 2014, 06:14:49 PM

Title: LPT Led´s
Post by: kak on June 27, 2014, 06:14:49 PM

Hello

I have my old cnc computer (which works great, but recently is freezing a lot)  so I just got a little younger Dell Optiplex 780 and have some problems with it.

The touch off plate which is connected to pin 15 is not working.  Probe Led is On all the time and when I change active high/low its off all the time.

There are the same settings on both computers, but the 2 rows of led´s, showing LPT pins in Diagnostics are showing different connections. Not the same led´s are On, on the 2 computers.

Someone told me it could be a driver, but what can I do about it?
Maybe thats the reason my touch off plate is not working.

X,Y,Z axis are running fine.


 

Title: Re: LPT Led´s
Post by: Tweakie.CNC on June 28, 2014, 02:03:25 AM

Hi Kak,

The Port 1 Pins current State LED's may not be working correctly. This is a long standing problem and not a fault of your PC so do not rely on them for information about your system setup.

Regarding your touch plate problem, have you changed anything else apart from the PC ?

Tweakie.

Title: Re: LPT Led´s
Post by: kak on June 28, 2014, 09:28:58 AM

Thanks Tweakie.

One more observation. When I start Mach3,  the Digitize led in Diagnostics is Off.   When I just touch the touch off plate once, the Digitize led turns On and stays On. Like there was some kind of Hold fixture.

I can only turn it off pushing Reset.

Title: Re: LPT Led´s
Post by: ger21 on June 28, 2014, 09:47:15 AM

Sounds like you have an issue with your breakout board or wiring.

Title: Re: LPT Led´s
Post by: kak on June 28, 2014, 09:59:59 AM

Thanks, but It works fine on my older PC with the same settings. I just move LPT cable from one PC to another. 

Is it possible to find some older LPT drivers for Mach3? I would like to try that.  Do I have to reinstall all Mach3 if I do that?

Title: Re: LPT Led´s
Post by: ger21 on June 28, 2014, 10:21:42 AM

Then it may be an issue with the PC's parallel port, or it's bios settings. What mode is the port set to in the bios?

Title: Re: LPT Led´s
Post by: kak on June 28, 2014, 10:43:29 AM

There is no EPP/ECP option in the Bios.

There is:
Disable
AT
PS2
EPP
ECP NO DMA
ECP DMA1
ECP DMA3

I have try to messure Voltage on LPT Dir pins of all the options - there is 0.2V  to  3,35V.  But in ECP DMA1 mode - Y and Z axis Dir pins are not working ( thats pin 5 and 7).
There should be about 5V I think.

There is 4.32V on pin 15 - where my touch off plate is connected.
There is also 4.32V on the other pins 10 -13. I use pin 10 for limit switches and they are working fine.  

Title: Re: LPT Led´s
Post by: ger21 on June 28, 2014, 11:02:55 AM

What breakout board are you using?
Have you tried AT or PS2 modes?

Title: Re: LPT Led´s
Post by: kak on June 28, 2014, 11:48:07 AM

I don´t think the breakout board has a name :-)  But motor drivers are 3x M542. I´ve bought it all Ready to go in a case, with PSU, softstart, BOB, drivers from a guy who sells a lot of them, or did 4 years ago.

Yes, AT and PS2 are doing the same.

When I actualy try to Zero with the machine running and push the zero button, Z axis i moving few steps down and Zero the Z DRO - noise in Dell PC?
But I can do it only once, bacause the Digitize led stays On.

Title: Re: LPT Led´s
Post by: Tweakie.CNC on June 28, 2014, 12:29:22 PM

Kak,

May I suggest you try connecting a 'pull-up' resistor of say 10,000 ohms (10k) between the touch plate pin (pin 15 ?) and +5 volts and see if this cures the problem.

Tweakie.

Title: Re: LPT Led´s
Post by: kak on June 29, 2014, 05:46:56 PM

Thanks for all the answers.

I solved the problem, and I hope it will stay that way :-)

I installed PCI LPT card and disabled the one on motherboard and my touch off plate is working.
So there must be something wrong with LPT on motherboard.

Title: Re: LPT Led´s
Post by: Tweakie.CNC on June 30, 2014, 01:28:03 AM

Great news Kak, I am pleased you have solved the problem.  ;)

Tweakie.