Problem- Mach 2 Headscratcher.....

[yohudi]

Have run into a bit of a weird problem with Mach 2 running below Win2k OS.. Tried everything I can think of to determine what the problem is.. I think it's with output from Mach 2... but I can't think of a reason to explain it or find a remedy....

I've been running a 4 axis configuration for a while.. without difficulty.. PC is an old 1.3Ghz AMD Athlon.. with just over 700MB Ram... Hard-Drive crash gave need to re-install OS and Mach 2 on a new drive.. Nothing else on the system. Copied in backed up xml files to re-establish tried and tested configuration...

4th axis is no longer functional.. DRO's move but no output from Mach 2 to BOB (cnc4pc C10 BOB).

Not a cable issue - is same cable as previously. Also exchanging A axis and Z axis pin outs shows correct response on BOB pin 14 and Pin 9 LED's for jogging and MDI motion. Voltage at pins is 4.85 volts when Z axis is using them. 0 volts when A Axis is configured to same pins.

Problem transfers with A Axis... i.e

normal Z setup is pin 3 = Step - pin 4 = Dir
normal A setup is pin14 = Step - pin 9 = Dir

Z axis/BOB led's are fine using either setting.. Problem with output occurs on pins 3 and 4 when A Axis is setup to use Z settings.

XYZ axes fully functional... just no output to BOB from Mach 2 using programmed, MDI or jogged motion on A Axis. A is active in ports and pins setup and shows as enabled (i.e value of 1) in .XML file. Is active in toolpath setup...

Motor/ Drive are OK ... Getting 'holding' current/voltage to A axis motor.. cant budge it when machine is on, no protest from or heating of motor. A Axis works fine when I run it on X,Y or Z output, just NOT getting any output to BOB to drive the axis from Mach2 for some unfathomable reason...

Anyone have any suggestions ?

Thanks in advance for any assistance..

Danny

[yohudi]

To anyone interested really...

Have made some progress on this today... I think it's a combined software / hardware problem....

For some reason the Mach 2 driver lost the ability to communicate with pins 14 and 9 on the breakout board.. this is definite at this point. I setup Mach 3 today... Mach 3 produces correct BOB response on all pins.. as indicated by LED's... Mach 2 still fails to send A axis motion to ANY of the BOB pins...

so problem solved then.... well not quite... Even though BOB seems to function correctly under Mach 3.. A Axis motor STILL will not move if driven by pins 14 and 9.. Swapping A Axis and X,Y or Z Axis motor drive inputs results in correct function of A. NONE of the other axes will drive from A Axis BOB output, even with motor settings adjusted to suit.

Voltage from all BOB outputs is 4.85 volts.. but there must be some difference with output on pins 14 and 9. Would probably need to examine BOB output using an oscilliscope to chase this further.. I don't have access to a 'scope' so this isn't going to happen. Will be easier to replace the cnc4pc BOB with something a bit more upmarket.. probably one of Bob Campbell's boards.

I originally bought 2 x cnc4pc BOB's, a charge pump and a couple of relays about 2 and 1/2 years ago.. So far 1 of the relays and both BOB's have failed. I'm not inclined to buy cnc4pc again.. Could be that I'm expecting a bit much from them for what they cost..

Can't see that BOB was damaged by harddrive crash. Controller was connected but not switched on at the time.. cnc4pc BOB was connected to printer port and would have been drawing power from USB as well... but would this have created the fault on the BOB ??? I can't say.. and to be honest I don't really care at this point.. as won't bring the BOB back to life anyway....



TTFN

Danny

[neilw20]

Have you tried various BIOS setting for the printer port.
I have noticed that regardless of the setting Mach3 seems to find the port and work. Maybe Mach2 can't find it because of BIOS setting. Just a thought.
Pin 9 is data line D7 and may have different output characteristics to pin 14 (auto feed).
I suggest a look at http://en.wikipedia.org/wiki/IEEE_1284
Many other links there will help you understand the operation in more detail.
There are many reasons and configurations that may not work as expected.
If it worked before you just haven't found the problem yet.
Try SPP EPP and ECP modes.
Try the zipped file. It will show the settings.
LPTST /? will show the options.
Works best if you run it from a DOS prompt otherwise the window disappears on exit.

[LeeWay]

I would try using a different pin if possible other than 14. I have had trouble with both pin 14 and 17 on various BOB's in the past when using them to run my spindle. No clue why. Why not use pin 8?

[yohudi]

Hi there,

Many thanks for taking the time to chip in some ideas...

neilw20

Thanks for the info and the link... Printer ports will be the subject of investigation today.. I have a 2nd port card I've always meant to install to get the machine to 6 axis setup.. so I'll check the existing and new port as you suggest.

LeeWay

It's difficult to adjust any of the pin out arrangements without impacting on one of the other axes or machine functions... I have 3 relays in the box as well.. but that might be a way round it which I'll check today... relays only need switching voltage.. and I am getting voltage...

I should have this sorted out today... even if I have to break out the other BOB that failed... this never really worked properly as I remember.. but I think there will be at least 6 pins on there that do work ok.. which should let me setup the existing BOB to drive the linear axes.. and the 2nd to drive rotaries.

To be honest I was going to setup this kind of arrangement anyway.. just not right now... which is part of the problem... I've invested that much time chasing down problems that I'm falling behind with other things.. so one way or another I'm resolving it.. today...

Edit: Should have said this before.. the original controller build is fully documented with photos etc in my build log at the link below..

http://www.cnczone.com/forums/showthread.php?t=20656

Thanks again for the suggestions and info

Danny

[yohudi]

Happy to say I have a solution in place...

Mach 2 is still not driving the 4th axis under any circumstances... probably something to do with the driver. Drivertest.exe reports everything ok and runs 3 axes no problemo... but 4th axis motion is not getting to the printer port(s). I don't know why Mach 2 now fails on the 4th axis.. I don't care.. I just want a functional machine...

LPTST reported LPT1 as being in 'Standard' mode.. which matched the BIOs setting.. address of 378.. as to be expected. Change to ECP or EPP made no difference to the problem...

"Repair" involved setup of Mach 3.. change of 2nd parallel adaptor... rewiring of BOB's to account for no output on pins 1, 9 and 14 on BOB1 ... thought only 9 and 14 were affected, but testing showed pin 1 was also defective... Had to change 2nd parallel adaptor as Mach 3 didn't like the existing port.. didn't know this... Previously all 4 axes had run from BOB1. Will upgrade to a Bob Campbell designs board in the near future I think... lost confidence in the cnc4pc product at this point.

Wasn't a difficult fix.. and should have arrived at it earlier... that's what you get for working the problem.. rather than working towards the fastest solution....

Thanks again for the contributions...

Danny