Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: edkathy1 on August 10, 2018, 03:12:58 PM
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Need help – I was given a home made CNC that has not been used in a few years. The configuration is not available for Mach3. Using Gecko model 251X drivers and a 30 V power supply. When connected I get the steppers to energize but can’t get any movement on X Y or Z. I have tried changing configuration no help, the only thing I did notice if you hold the stepper shaft and try to Jog the stepper you can feel like 1 pulse but no movement. I do not have a scope to check input signals. I am at a loss as to what to do next.
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Hi,
its not clear...are you using Mach3 or Mach4?
What sort of PC are you using? What version of Windows and is it 32 or 64 bit?
Are you using a parallel port or an external motion controller?
Craig
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Mach 3
parallel port
windows XP
32 bit
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Hi,
this board is about Mach4, you'll get more help if you post in the Mach3 General Discussion board.
If you run DriverTest.exe what results do you get, not just an 'excellent' report, the numbers please or
a screenshot.
Craig
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One pulse for each jog attempt sounds like you may have the step and directions signals interchanged with each other.
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I have 2 CNC machines my old one and the one I am trying to get to work. The one with the problem has been in storage for 2-3 years. After all the testing I have done I think the drivers are defective. This is hard for me to accept, all 3 bad. I did take the parallel cable and moved it to my CNC and it worked fine ( both CNC’s have gecko drivers 250/250X ) This is why I think the configuration is correct. Not having a scope I looked at the speed and directions pins of the Gecko drive with a VOM, I can see some change as I jog the steppers.I have been waiting for Gecko to get back to me as how to check the drivers for proper operation.
I did check the input and direction wiring
Below is the results from the driver test
Driver Test
Interrupt 00
Pulse/sec 23690
CPU Speed 2999
Apic Timing Constant 8442
Short time 41 4878
Longest 43 90 ( Numbers keep changing )
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Hi,
it sounds like the DriverTest.exe numbers are good.
You say you took the parallel cable and plugged it into your CNC. I'm guessing you mean taking the parallel port cable from the PC
running the potentially faulty setup and plugged it into the BoB of your working machine. Is this correct?
If it is it rather proves the PC and Machs parallel port driver and the parallel port itself are OK. That rather points to the BoB and/or
your drivers, the same conclusion you have reached. I agree it seems strange that all three Geckos should fail, they are pretty reliable.
I would suspect then the BoB.
Does the BoB have a charge pump or other signal to enable the whole board?
Does the BoB have any LEDs on the motor outputs that would indicate that signal are progressing to the output of the BoB?
Do you have an Estop hooked up? If you do does activating the Estop disable Mach? I use this test as a means of establishing
whether an input to the BoB is progressing through the BoB to the parallel port and then to Mach.
Do you have a motor enable signal? If you do can you use either Machs output active high/active low setting to toggle the enable output
of the BoB that you could measure with a multimeter? Note you could do the same thing by setting Machs enable output to be active and then
enable/disable Mach which should toggle the BoB output.
Craig
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In answer to the question I just move the parallel cable from one CNC to the other.
The E-Stop does activate the software
There are no electronics on the Break out Board ( BoB ) I am posting pictures of the Bob and drivers.
This CNC worked with the wiring as you see in the pictures. The cut wires on pin 11 & 21 was for a probe we were trying when we built the CNC.
Will call Gecko tomorrow see what help they can give to test the drivers stand alone.
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Hi,
could it be that the PC you are using is producing 3.3V signals whereas the Geckos require 5V.
Do you have a multimeter?
Craig
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Actually 3.3 volts does meet the specifications of the G251X drivers.
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I used the same computer 6 months ago and now when I try open MACH3 it shuts the computer down, I have uninstalled and reinstalled MACH 3 and still shuts down. All my other applications work on the computer just MACH 3 is the issue. I was told to uninstall some new updates and still having the same issues, any suggestions?
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Hi,
there are still one or more updates on your PC which are causing that. If you cant remove them you may have to do
a Restore to a point where it still worked. Thereafter you will have to disable Windows updates or keep the PC off the net.
This problem affects the parallel port. You might want to consider an external motion controller like a SmoothStepper which
are unaffected.
Craig
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Yes i have a mulit meter
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Hi,
then measure the voltage between the X Dir pin, looks to be pin 2 or 3 and earth with an X move in one direction and then
again but with the X axis moving in the other direction.
It might be 0, or thereabout one way and 5V , or thereabout the other way.
Craig
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The direction goes from 56.5 mv in one direction to 3.31 v in the other.
The spec on the 251X says the direction and step can be driven with 3.3V or 5V logic inly input current will change from -1ma to -.67ma for login "O"
I really want to thank you for help on this problem.
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Hi,
OK it sounds increasingly like the drivers. Do they have an enable input? If they do it it active?
Craig
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Craig -- I got it - it works your suggestion to check the level of the direction pin Got me in the ballpark to find the problem. To make a long story short the step and direction pins in the configuration did not match the wiring. This is why if I plugged the parallel cable from one CNC to the other one worked and one did not, gave you the impression that the config and software were correct. The fact that we did not have the correct files that went with the machine when it was built caused all the problems.
MANY THANKS FOR YOUR HELP
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Hi,
kool, glad you got it sorted. Of course that means that Steve Stallings called it right a while back!
Craig
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I had my head in a very dark place