Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: MachBruce on March 28, 2009, 08:04:58 AM

Title: Parallel port woes
Post by: MachBruce on March 28, 2009, 08:04:58 AM

Something to share,


My Machine has been working beautifully for some time until recently when a couple of intermittent glitches have appeared. False limits, lost steps appeared from nowwhere. I have spent a whole day trying to track own the problem. I tracked it down to the parallel ports in my PC.  What was the cause? I reloaded Mach3 and did more check - the machine doesn't even move now.  More investigation revealed that the motion controller I purchased as a "plug and play" had a pull up voltage of 12v applied to the limit switch input of parallel port.  I have learnt a lesson from this. Check the stuff that we buy and make sure its OK and not just plug it in.

Moving along now - beckons this points.

What should have been in the controller to prevent this?  

I believe that any voltage over 5v applied applied to the parallel port can cause damage to the port and thus the mother board.

Should we always use a buffer board before the parallel port input?

Do the parallel port inputs require an extra pull up of 5v or can we rely on the pull up from the PC parallel port?


All I know is that I have  get another PC and I also need to modify the controller I am using.

Lesson learned.  I hope this will prevent some one else experiencing similar problems.

Bruce

Title: Re: Parallel port woes
Post by: Hood on March 28, 2009, 08:20:15 AM

What is the motion control device you are using?
Hood

Title: Re: Parallel port woes
Post by: MachBruce on March 28, 2009, 04:51:45 PM

Im am not sure if i should mention brand names here?

Title: Re: Parallel port woes
Post by: Hood on March 28, 2009, 05:36:12 PM

No problem, was just curious thats all :)
Hood

Title: Re: Parallel port woes
Post by: MachBruce on March 28, 2009, 07:08:29 PM

Seeng that I have to repair / upgrade, I am considering buying a "warp9 smooth stepper" and a CNC4PC C23 - Dual Port Multifunction CNC Board

Is this a good choice for a robust system?

Bruce

Title: Re: Parallel port woes
Post by: Hood on March 28, 2009, 07:13:12 PM

SmoothStepper is a good choice in my opinion, have 4 of them, three on working machines and another waiting for me to get my arse in gear and get the Beaver Mill finished.
As for the CNC4PC cant say, never had any of their boards.
Hood

Title: Re: Parallel port woes
Post by: MachBruce on March 28, 2009, 07:21:04 PM

the C23 board seem to offer allot of features in addition to being a compatible breakout for the smooth stepper

http://www.cnc4pc.com/Store/osc/product_info.php?cPath=33&products_id=182

Bruce

Title: Re: Parallel port woes
Post by: Hood on March 28, 2009, 07:23:00 PM

Yes, seems to, personally I dont like all these multifunction boards, as I said no personal experience just think there is too much going on with them.
Hood

Title: Re: Parallel port woes
Post by: MachBruce on March 28, 2009, 07:45:41 PM

do you use a break out with the smooth stepper , if so what type?

thanks,

Bruce

Title: Re: Parallel port woes
Post by: Hood on March 28, 2009, 08:02:17 PM

I use PMDX122 on all machines and also have CNC Building Blocks Acustep on the lathe and Beaver Mill. The reason I had the Acustep was for Index homing but they are no longer available, however  I now do that in my servo drives so if I do another machine it will be two PMDX.
 I am not saying you shouldnt get the multifunction boards, just I prefer the simpler aproach of seperate components, one reason is if a part goes wrong you dont have to replace the whole thing.
Hood

Title: Re: Parallel port woes
Post by: MachBruce on March 29, 2009, 07:36:20 AM

thanks for the advice,

Bruce