Messages

51

FAQs / Re: Losing steps or something?

« on: October 04, 2010, 04:46:07 PM »

Ah, I will try that, too.  See the following post for some interesting results prior to getting your most recent suggestion, though.
Thanks, Don

52

FAQs / Re: Losing steps or something?

« on: October 04, 2010, 01:49:18 AM »

Hi, rcaffin.  I have tried 0V common and it runs terribly jerky with the breakout board.  Gecko suggested some years ago to use the +5V com. setting as it is supposed to reject noise better.  I'd like to know where the "noise" is coming from.  When I originally was having this problem I was using a move of 1.00 inches.  50 iterations of that took a long time, so I shortened up the distance.  I can see that if this was allowed to go on, a large part run might get ugly real fast.  Aren't computers supposed to do what they are told?  Don 
I'll try changing the program though to see if it has any effect.  Thanks for the suggestion.

53

FAQs / Re: Losing steps or something?

« on: October 04, 2010, 01:38:25 AM »

Hi dan.  I will have to try that tomorrow.  Its getting toward 10:40 PM here in the Seattle ares and the kids bedrooms are right over the garage shop.  I don't want to wake them.   Are you suggesting that I swap the cheater cables from the parallel port to the drives?  I'll try that and report back.  Thanks for the suggestion.
Don

54

FAQs / Re: Losing steps or something?

« on: October 04, 2010, 01:13:45 AM »

Hi everybody.  I installed the NetMos PCI parallel port card in the new Intel computer.  Installation went well.  Whew!  I'm not really a great computer geek, so these things sometimes worry me.

Voltage from the NetMos is +5 volts.  Duh!  A clue here.  My Geckos are set for +5V common!  No wonder they wouldn't run. 
I switched them over to 0V common, and hooked up my D-sub 25 cheater cable.  Now the machine runs.  But...
     Backwards.  Makes sense because of the direction polarity.  I switched it over in the motor outputs to get it right. 
      Errors...  The machine ran better than it had when running from the B.O.B. In 0v common mode.  However,  Both axes offset.  X axis +.005” and Y axis +.007 or so...Hmm.  I changed line 5 of the program to X-.1Y-.1 and ran the program.  Now X-axis returns to zero, but the Y axis is offsetting about .0025” each run of the program!
   Using 0V common, and no B.O.B. Changes the direction of the offsetting behavior, and introduces an apparent +.0025” offset per run of the program.

   I set everything back over to the LPT1 3.3V parallel port.  Geckos run...  with motor outputs page set for direction active low, the machine runs in the correct directions, but running the G1X+.1Y+.1 program, X axis offsets -.005” every time, but the Y axis offset has been irregular.  It seems to range from +.0075” to as much as +.0125 in the 50 iterations of the program!  Hmm.
   My brain is straining.  I realize that the irregularity may be coming from the same source that caused the machine to run jerky with the BOB set to 0v common, but I don't get why now with the machine going positive in both axes, the X axis consistently offsets -.005”  and the Y axis is offsetting + some amount more each run of the program.  I'm wondering if this is a noise issue as well as a program execution error.  Help would be appreciated.  Thanks for your continued support. 
Don

55

FAQs / Re: Losing steps or something?

« on: October 01, 2010, 03:28:07 PM »

Hi,again.  I was typing while you were posting.  Looks like insufficient current isn't the problem. But what could it be?
Don

56

FAQs / Re: Losing steps or something?

« on: October 01, 2010, 03:25:11 PM »

Hi, Again Dan.  I still had the d-sub cheater cable hooked up from yesterday so I checked voltages at the Gecko terminals.
Voltage on Dir pin at computer startup goes to 4.8 V and stays there even after turning on the Gecko Power supply.  I started Mach3 and loaded the diagonal program.  While running, the voltage fluctuates between 4.3 and 4.8 volts on my meter.  I suspect slow meter response time...  I slowed the feedrate to F5 in the program, and now the fluctuation is from 4.6V to 4.9V on the direction pin of the gecko.  This being referenced from the com terminal.  I hope this is helpful in some way. 

57

FAQs / Re: Losing steps or something?

« on: October 01, 2010, 02:51:29 PM »

Hi, Dan
Nothing was connected to the D-sub 25 pin cable.  Just the voltmeter.  The plug is a male plug and plugs right into the parallel port.  I'll try measuring the voltage at the gecko terminal block while it is attempting to run...  Why would it work with the B.O.B. but not the Gecko?  Don

58

FAQs / Re: Losing steps or something?

« on: October 01, 2010, 05:26:11 AM »

Hi, again.  I hooked up a digital volt meter to the direction pin of X axis of the parallel port on the Intel based computer.  When I powered up the computer, the pin went to 3.3V.  As soon as I start Mach3, the pin goes to zero volts.  I expected it to toggle back and forth when the program runs, but it stays reading 0V the whole time...   Pins used are pin 3 is Direction and pin 18 is common. 
   My setup is configured so that pin 2 is X-axis step, Pin 3 is X-axis Dir., pin4 is Y-axis step, pin 5 is Y-axis direction, etc.  Since I twisted the one pair of X-axis motor leads, all three axes are direction active “hi”.  All step pins are set active low.
   The old PC Chips computer has a NetMos PCI parallel port card on it that I used with an MPG.  I decided to check it out.  When firing up that computer, the NetMos reads 5.0V on pin 3 until I start Mach3.  Then it too goes to 0V.  I set all the motor outputs to port 2 and plugged it into the PMDX breakout board.  Running the diagonal program X+ Y+ resulted in both axes offsetting -.005”.  Running the program with X- and Y- yields perfect return to zero.  Yada, yada.  It seems that with this parallel port card the polarity of the direction of commanded movement under which the error occurs is reversed from the other computer.  The error is still offset to the negative direction as with the other computer, but now it only occurs when the affected axis is starting out in the positive direction.  Strange.
   I then tried to take the breakout board out of the equation.  I have a D-sub 25 male connector that I have used that has 3 separate shielded cables with 4 conductors each.  Each cable is wired for an axis so that I can hook it up to a gecko drive directly.  Shield goes to earth ground.  One wire to com., one to step, and one to direction.  As the Geckos are set to +5 volt logic, it should work.  Right?  Result is no movement at all.  I checked everything but for some reason, even the NetMos 5V card doesn't drive the Geckos.  Huh?  I'm not sure how this TTL stuff works.  And yes, I tried reversing the Step and direction settings.  No dice.
   I plan to hook up the NetMos PP card in the new computer soon, installing the drivers was a pain last time, and then see what effect that has on the symptoms...

Thanks for your help,
Don

59

FAQs / Re: Losing steps or something?

« on: September 29, 2010, 05:26:37 PM »

I have substituted a CNC4PC model C10 B.O.B.  and it had no difference in behavior.  I'm trying to cobble together a pc with an Asus A-7N8X-E delux motherboard,  It is about 6 years old.  It would be nice to bypass the P.P. completely, but I'll have to see...   I've been wondering if the SmoothStepper would work.  It is a possibility if it doesn't create another can of worms.
Don

60

FAQs / Re: Losing steps or something?

« on: September 29, 2010, 05:00:44 AM »

   

I'll try to un-install the Mach program and delete the folders and reinstall when I can to see if that changes anything.  I doubt it as the problem has occurred with 2 computers and 2 versions of mach3. 
I am curious as to what Enhanced pulsing doed in General Config. It is checked in my setup, and seems to be the default setting. 
 Don