[Crevice Reamer]

Congratulations John!!

CR.

[John V]

Congratulations John!!

CR.

Thank you much! I also thank you for your site. If I wouldn't have found that I'm not sure if I would have jumped into this project.

I do have a question regarding the home switches. You said to run them in series, but recommended that I use shielded wire. Why is this?

I am planning on doing the x,y,z in series and then grounding the drain wire to the psu ground. Would this be the correct setup? I thought I would have to do them separately in order for mach3 to recognize it.

Any help would be great!

[Crevice Reamer]

Thank you much! I also thank you for your site. If I wouldn't have found that I'm not sure if I would have jumped into this project.

I do have a question regarding the home switches. You said to run them in series, but recommended that I use shielded wire. Why is this?

I am planning on doing the x,y,z in series and then grounding the drain wire to the psu ground. Would this be the correct setup? I thought I would have to do them separately in order for mach3 to recognize it.

Any help would be great!

Mach3 knows where all the switches are. During a cutting operation, if it encounters a switch, it assumes it to be a limit and shuts down. During homing, it first moves the Z until encountering a switch, recognizes home, and backs off a trifle to close the switch. Then it will home the X, and then the Y. Because limits and homes are used in two completely separate operations, it has no trouble doing this.

CR.

[John V]

Mach3 knows where all the switches are. During a cutting operation, if it encounters a switch, it assumes it to be a limit and shuts down. During homing, it first moves the Z until encountering a switch, recognizes home, and backs off a trifle to close the switch. Then it will home the X, and then the Y. Because limits and homes are used in two completely separate operations, it has no trouble doing this.

CR.

Ok. Would you recommend having limit switches as well? Or would I be ok with just using soft limits within mach3?

What CAM software do you use?

Thanks!

[Crevice Reamer]

It's a personal choice. I don't use limits with steppers and rely on soft limits. Others feel safer with limits. Home switches are mandatory though, (as are limits with servos) and you might as well use them for limits also.

BTW: Even if you go for limits, it's almost impossible to limit the bottom travel of Z. Too many different tool heights.

CR.

[rkovvur]

So I restarted the computer and re attached the 25pin cable and moved some of the wires around and now everything works....

I am glad everything works.. but still a little confused at what actually made it work.
--

I think they key was your restarting the PC. If you have XP and if you used Mach3, then the initial control of the parallel port driver is held by XP. Most stepper drivers have a stop input pin that shuts down the stepper (holds them in place). Possibly this pin was driven actively by XP until you restarted when the Mach3 driver took over.

[Crevice Reamer]

I do have a question regarding the home switches. You said to run them in series, but recommended that I use shielded wire. Why is this?

Small Voltages and tiny currents in these circuits are subject to influence of "cross talk" from neighboring wires. This can cause frustrating false limit or Estop signals which stop your program in the middle.

Proper shielded twisted pair wire virtually prevents this.

CR.