Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: Jerrypower on March 24, 2018, 09:04:12 AM

Title: Low voltage on stepper port issues
Post by: Jerrypower on March 24, 2018, 09:04:12 AM
Hello,

I have some issues with a CnC machine.

The Z axis doesn't work at all.
When measuring the current going through the pins and comparing it to the other axis then the step pin has a permanent 0.21v and thus doesn't work.
I've swapped the cables from the other axis to this one and vice versa and could conclude that there is no issues with the motors and cables.

Measuring the cable it itself gives of 5v (Which all the other cables also does), but as soon as it is put in the step slot on the card it drops down to 0.21v.
No matter how much I try to move it in the mach3 software it doesn't work. It changes position in the mach3 program but refuses to work.

If I remove the cable from the card and then just touch it to the slot where it is supposed to be it does small jumps at first contact, as if the 5v tries to make it move, but then straight away drops down to 0.21v.

Does anyone have any idea how to further troubleshoot this?
Or is it possible to change the voltage at the step port from mach3 itself?

I've tried to start it from a clean profile, but also using the one provided as the software and machine were purchased.

I'm attaching the image of the card as well as the xml.

If you have any idea on how to fix it, or to further troubleshoot to figure out what it is then please tell me! :D
If you need any additional information, then please tell me asap and I'll provide it as fast as i can!



Regards
/Jerry

EDIT: I might have double posted a bit here as it didn't seem to accept it.
Title: Re: Low voltage on stepper port issues
Post by: Tweakie.CNC on March 24, 2018, 09:23:46 AM
Hi Jerry,

Can you confirm that the X an Y axis is working OK - it is just the Z axis which is not working ?

Tweakie.
Title: Re: Low voltage on stepper port issues
Post by: Jerrypower on March 24, 2018, 09:27:04 AM
X Y and A is working like a charm.
As I mentioned in the first post I moved the wires from Z to X just to test and see if there was any kind of issue with the motors, but they worked there.
And at the same time I also put the working X motors and wires to the Z slot and nothing happened, except the same low 0.21v.
Title: Re: Low voltage on stepper port issues
Post by: TPS on March 24, 2018, 09:39:14 AM
had a quick look to your XML.
everthing in there should be ok.

can you please post the Picture of your Card, something went wrong, when you tryed to post it.
Title: Re: Low voltage on stepper port issues
Post by: Jerrypower on March 24, 2018, 09:41:13 AM
Seems the pictures was too large so I put them here https://imgur.com/a/ITwEF
If it is Ok to post links to imgur.
Title: Re: Low voltage on stepper port issues
Post by: TPS on March 24, 2018, 09:53:43 AM
Looks like your Card/port is faulty on pin 6/7.

on the Picture i can see you have a 5th.

just for a test hook axis Z to the 5Th axis

and confiure your Z axis step to pin1 and dir to pin14 
Title: Re: Low voltage on stepper port issues
Post by: Jerrypower on March 24, 2018, 09:55:30 AM
The 5th slot for the B axis is also dead, no response at all in voltage. And din't work when we tried it.
Title: Re: Low voltage on stepper port issues
Post by: TPS on March 24, 2018, 10:04:22 AM
so it Looks lick you have a bad Card with no Options left, then to replace it.
Title: Re: Low voltage on stepper port issues
Post by: Jerrypower on March 24, 2018, 10:24:51 AM
But it worked about one or two years ago.
Is it common that these things breaks?
Title: Re: Low voltage on stepper port issues
Post by: TPS on March 24, 2018, 10:29:36 AM
so have swapped the Z wires on your BOB, and it worked fine.
-means Motor Controller and Motor and motro wiring is ok.

so what else is left as the bob ?

 
Title: Re: Low voltage on stepper port issues
Post by: Jerrypower on March 24, 2018, 10:32:53 AM
I'm bad with these terms, What doe BoB stand for?
Title: Re: Low voltage on stepper port issues
Post by: TPS on March 24, 2018, 10:33:41 AM
breakoutboard
Title: Re: Low voltage on stepper port issues
Post by: Jerrypower on March 24, 2018, 10:51:03 AM
There are no other ways to do the wires to get it to work that i know of.
But is there any way to control the output from the mach3 program, or something else we could do to troubleshoot it?
Title: Re: Low voltage on stepper port issues
Post by: TPS on March 24, 2018, 10:57:37 AM
you can check the direct signals from the parallel port (pin 6/7 from 25pole Sub D), with oszilloscope.

Title: Re: Low voltage on stepper port issues
Post by: Jerrypower on March 24, 2018, 11:00:05 AM
I'll keep that in mind and try it as soon as I can.
Thanks.

Though, could it be the parallel port that is doing this? To get lower voltage at the card.
Title: Re: Low voltage on stepper port issues
Post by: Tweakie.CNC on March 25, 2018, 02:00:20 AM
Quote
Though, could it be the parallel port that is doing this? To get lower voltage at the card.

You can check if it is the parallel port that has the problem...

Note the two pins that you are using for Z axis.
In Ports and Pins / Motor Outputs configuration swap X axis pins for Z axis pins.
If Z axis now works and X axis does not work then it is the LPT parallel port that needs replacing.
If Z axis still does not work but X axis does then it is your driver card that needs replacing.

Tweakie.
Title: Re: Low voltage on stepper port issues
Post by: TPS on March 25, 2018, 04:55:19 AM
not realy,

because for example pin 6/7 will stll be connected to the same optocouples of the board (physicaly).

to do this test you have to swap Pins at the 25pol. Sub D (LPT Card or board side does not matter).
Title: Re: Low voltage on stepper port issues
Post by: Tweakie.CNC on March 25, 2018, 05:15:22 AM
You're right TPS, the physical pin connections have to be changed, please ignore my earlier post.

Tweakie.
Title: Re: Low voltage on stepper port issues
Post by: Jerrypower on March 26, 2018, 09:20:54 AM
Measuring the ports on the PC gives this result.
This is directly at the PC no cables in between.

pin2  4,79v
pin3  4,79v
pin4  4,79v
pin5  4,79v
pin6  3,1v
pin7 -0,249v

pin 2 is step for X
pin 3 is dir for X
pin 4 is step for Y
pin 5 is dir for Y
pin 6 is step for Z
pin 7 is dir for Z
Title: Re: Low voltage on stepper port issues
Post by: Inferno on April 01, 2018, 02:46:22 AM
Check the pins at the computer first. If OK at the computer, check at the end of the cable.
I just went through the same thing and discovered it was a bad cable.