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Please help me
« on: September 08, 2007, 01:37:49 AM »
Hi Friends,

Please help me,

For my hobby CNC project i decided to use MACH3 & stepper motor setup.

Currently i have finished my mechanical framings of Hobby CNC.

Now its time to run Stepper motor on Mach3 but facing problem to it so.
I have design bipolar stepper motor drive using L298 but when i tries
to run using Mach3 & printer port then it fails to work nothing is
happen.

I have preconfigure printer port pins as MACH3 software uses but still
not working.

Can anybody please guide how to resolve this problem.

Regards
Manoj
manoj_sakpal2000@yahoo.co.in

Offline Whacko

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Re: Please help me
« Reply #1 on: September 08, 2007, 01:33:47 PM »
You have to elaborate. How are you sequencing the step pulses to rotate the motor?

Whacko
Nothing's impossible
Re: Please help me
« Reply #2 on: September 10, 2007, 04:40:41 AM »
Hi Whacko

Thanks for the reply.

i am using normal stepper drive ckt with L298 which accepts steps & direction signal
I am using printer port configuration as mention in Mach3.

Could you please advice me what exactly you want me to elaborate.

Regards
Manoj

Offline jimpinder

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Re: Please help me
« Reply #3 on: September 10, 2007, 09:13:53 AM »
I take it you are using a lead from the printer port. I used an old printer cable which I then cut in two. I identified all the pins with each wire and soldered the 25 wires in order 1 - 25 onto a small piece of copper clad strip board.

If you look in Config/Ports and Pins/Motor Output, you can then specify which pins you want the signal to come out of. These are usually 2 and 3, 4 and 5, 6 and 7 for the first three motors. Do not forget to specify Port 1 in the ports column.

You can test if there is any signal on the pins by connecting a TTL/Cmos logic probe to each pin and trying to jog ( without any cards or anything connected). Pins 2,3,4,5,6,7,8, and 9 are the eight outputs used in the stepper motor page. Pins 10,11,12,13 and 15 are inputs. Pins 1,14,16 and 17 are the other four outputs. Pins 18 to 25 are signal ground - and you will need to connect at least one of these to be able to read the port.

You should get a "pulse" reading on the logic probe if a signal is being output.

You can test your cards simply by tapping a positive or negative wire on the "step" input - the motor attached to the driver should react even if it is only a small movement.

If you are getting some signal out on your printer wire, and your cards are giving some signal to the motor, connect up the wired as you have specified in "ports and pins" and it should work.


Not me driving the engine - I'm better looking.

Offline Whacko

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Re: Please help me
« Reply #4 on: September 10, 2007, 02:13:15 PM »
I propose you download the "Customising Mach2" document in the download section of Art's website. It is very well explained. There is also video tutorials you can watch or download. You'd need a broadband connection to download, they are quite big. Also check out the Wiki.

If you still battle, let us know.

Whacko
Nothing's impossible
Re: Please help me
« Reply #5 on: September 11, 2007, 12:46:09 AM »
Hi
Thanks
I will reply you asap.

Regards
Manoj

I take it you are using a lead from the printer port. I used an old printer cable which I then cut in two. I identified all the pins with each wire and soldered the 25 wires in order 1 - 25 onto a small piece of copper clad strip board.

If you look in Config/Ports and Pins/Motor Output, you can then specify which pins you want the signal to come out of. These are usually 2 and 3, 4 and 5, 6 and 7 for the first three motors. Do not forget to specify Port 1 in the ports column.

You can test if there is any signal on the pins by connecting a TTL/Cmos logic probe to each pin and trying to jog ( without any cards or anything connected). Pins 2,3,4,5,6,7,8, and 9 are the eight outputs used in the stepper motor page. Pins 10,11,12,13 and 15 are inputs. Pins 1,14,16 and 17 are the other four outputs. Pins 18 to 25 are signal ground - and you will need to connect at least one of these to be able to read the port.

You should get a "pulse" reading on the logic probe if a signal is being output.

You can test your cards simply by tapping a positive or negative wire on the "step" input - the motor attached to the driver should react even if it is only a small movement.

If you are getting some signal out on your printer wire, and your cards are giving some signal to the motor, connect up the wired as you have specified in "ports and pins" and it should work.



Re: Please help me
« Reply #6 on: September 13, 2007, 12:18:12 AM »
Hi

When i checked supply voltage across printer port pins they are very small like 3.5v & some times 0.42v.

I am using computer of Intel P2 (2.4Ghz processor , 512 RAM DDR)

regards
manoj




I take it you are using a lead from the printer port. I used an old printer cable which I then cut in two. I identified all the pins with each wire and soldered the 25 wires in order 1 - 25 onto a small piece of copper clad strip board.

If you look in Config/Ports and Pins/Motor Output, you can then specify which pins you want the signal to come out of. These are usually 2 and 3, 4 and 5, 6 and 7 for the first three motors. Do not forget to specify Port 1 in the ports column.

You can test if there is any signal on the pins by connecting a TTL/Cmos logic probe to each pin and trying to jog ( without any cards or anything connected). Pins 2,3,4,5,6,7,8, and 9 are the eight outputs used in the stepper motor page. Pins 10,11,12,13 and 15 are inputs. Pins 1,14,16 and 17 are the other four outputs. Pins 18 to 25 are signal ground - and you will need to connect at least one of these to be able to read the port.

You should get a "pulse" reading on the logic probe if a signal is being output.

You can test your cards simply by tapping a positive or negative wire on the "step" input - the motor attached to the driver should react even if it is only a small movement.

If you are getting some signal out on your printer wire, and your cards are giving some signal to the motor, connect up the wired as you have specified in "ports and pins" and it should work.



Offline jimpinder

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Re: Please help me
« Reply #7 on: September 13, 2007, 06:29:52 AM »
It seems to me that you have a computer that uses 3.5v as plus.

Your problem might be that your driver cards cannot tell the difference between 0v (in your case 0.42v) and +v. In my case the outputs are 5v which my card can recognise.

You probably need an interface between the computer and the driver cards. I don't use one, but there are many "break out boards" on the market, usually with their own power supply, which, I would imagine will get over this problem.

You could, if you know what you are doing, put a pull up resistor between a positive supply and the input at your card. If you isolate this with a diode, then the resistor pulls the voltage up, and the 0.42v signal pulls the input down. You must be careful that the resistor is not too low a value as to overload the drivers of your LPT1 port.

You are, in effect building your own break out board, but I imagine this will be cheaper than buying one.
Not me driving the engine - I'm better looking.