[mhiggins]

I don't think it matters if Mach knows which one as long as it stops motion so it can't crash. The opertator will be able to tell which one by looking at the machine.

[Mr.Chips]

I don't think it matters if Mach knows which one as long as it stops motion so it can't crash. The opertator will be able to tell which one by looking at the machine.

Yes I underst andstopping isn't a problem, as any sw it hits it stops and backs up off the switch, but how does it know which direction home is?

[mhiggins]

I don't have mine all set up yet so I don't have a good answer for that. I suspect that unless it has completely lost its bearings, it should have some idea of where it is in absolute coordinates. If not, you might just have to manually move it off of the switch.

[Mr.Chips]

Rob, I sent a copy of this drawing to Dave to get his take on it. If I understand the Mach3 manual, we can use a single parport pin to run both limit switches on one axis. One of the limit switches can also act as a home switch. So all limit and home switches can be wired using three pins plus one ground. As I said before "If I understand the Mach3 manual". I will let you know when I hear back from Dave.

Any thoughts from those who have already done this would be welcome.

This method is correct. I can use it and just use three connnections rather than the four I thought I needed. I will go with this method and have one connector left over. Good thing I havent wired my switches yet. Thanks for the clarification.

Reference: “Using Mach3 Mill, Rev 1.84-A2 Page 4-10 section 4.6.4

In the second paragraph it explains using two switches in series and having one a limit and the other a limit/home. “You define, to Mach 3, a direction as the direction to travel to move when looking for a reference switch. The limit switch (vane or ramp) at that end of the axis is also the home switch.”

The term reference is interchangeable with home.

Hager

[mhiggins]

I'm glad it helped.

You probably shouldn't use my wiring diagram as a reference since I haven't actually tried it yet and don't know if the pinouts I have selected are correct. It was intended to help me better understand the wiring and to solicit input from others with more experience.

Mike

[Mr.Chips]

I'm glad it helped.

You probably shouldn't use my wiring diagram as a reference since I haven't actually tried it yet and don't know if the pinouts I have selected are correct. It was intended to help me better understand the wiring and to solicit input from others with more experience.

Mike

It is a very good drawing. I will simply change the pin out to fit my maching.
And the 4th connection which has now been freed up will be used for E-Stop.
My E-Stop switch has two lines one for the 4th connection and the other for the Transformer.

Your drawing has answered questions I hadn't asked yet.

Every Newbie needs this drawing.

Hager

[mhiggins]

It is a very good drawing. I will simply change the pin out to fit my maching.
And the 4th connection which has now been freed up will be used for E-Stop.
My E-Stop switch has two lines one for the 4th connection and the other for the Transformer.

Your drawing has answered questions I hadn't asked yet.

Every Newbie needs this drawing.

Hager

I'm glad you found it helpful.

If you are talking about using the e-stop for the transformer that powers the steppers as I show it in the drawing, you may want to hold off on that. Again, I am not certain, but cutting power to the steppers may cause the Z-axis to crash into the table since the motor would probably lose its holding torque when it loses power. In fact, I think I should probably change that on the drawing until I have tested this. I wouldn't want anyone to find out the hard way that I was wrong.

Mike

[mhiggins]

As far as my fear of cutting off power to the steppers and having the Z-axis fall to the table, I am over it. I think that it is possible with a very heavy machine with a ball screw or at least a screw with a fast pitch and little rolling resistance. A 10-pitch acme screw should support the axis without power to the motors. With that said, I will probably go ahead and wire my e-stop to cut power to the steppers.

Rob,

I have been in contact with Dave and it looks like my wiring diagram will work. He told me that he wires all of his limit switches in one big loop on one parallel port pin with normally closed switches. This way any break in the circuit will stop the machine. He wires the home switch for each axis to its own pin. This is a little different than my idea and uses four pins total. He recommends using shielded twisted pair cable for as much of the wiring as possible. If you would like to send me an email I will forward my questions and his responses to you.
[email protected]

[Mr.Chips]

As far as my fear of cutting off power to the steppers and having the Z-axis fall to the table, I am over it. I think that it is possible with a very heavy machine with a ball screw or at least a screw with a fast pitch and little rolling resistance. A 10-pitch acme screw should support the axis without power to the motors. With that said, I will probably go ahead and wire my e-stop to cut power to the steppers.

Rob,

I have been in contact with Dave and it looks like my wiring diagram will work. He told me that he wires all of his limit switches in one big loop on one parallel port pin with normally closed switches. This way any break in the circuit will stop the machine. He wires the home switch for each axis to its own pin. This is a little different than my idea and uses four pins total. He recommends using shielded twisted pair cable for as much of the wiring as possible. If you would like to send me an email I will forward my questions and his responses to you.
[email protected]

Thanks,

His way was like my last layout, but I'm using your layout. Both ways will work now that I understand how they work work with Mach3.

I started wiring my switches in today. Had to remake a couple of brackets because of interfearence.
I anm using 1/2" acme and delrin on this machine, so there is lots of friction, have had my router on it and it will not fall with the power off.
Good news about the E-Stop switch I'll use the drawing as my guide.

I'm using shielded wire and it looks twisted too, I didn't specify that when I baught it. Used shielded wire from controller to steppers too. Heard lots of stories about non shielded wire, sometime there is interference.

Thanks for the offer of email, I'll keep that in mind.

Thanks
Hager

[truman]

well here is another sign. And I also ordered my limit switches hopefully be here this week or first of next week.

[truman]

well here is the first alluminum part I cut on my machine I was very happy with it it was only out about 2thou. I screwed up when I made the toolpath by selecting inside instead of outside edge for the path to cut it out. I cut it at 30ipm and took 0.030" passes very light but well worth the wait if you are wondering what it is it is a bearing block hope to upgrade all of the hdpe. oh ya I used a two flute upcut carbide endmill at 16000 rpm.

[mhiggins]

Wow, that looks great. Have you already replaced your MDF gantry with aluminum? If so how about some pictures?

[truman]

no I havn't replaced it yet I am working on the small pieces right now that was all I cut so far but I will be cutting more soon and I will post everything as I go

Rob

[truman]

well I made some modifications and cut my bearing blocks in mdf they turned out perfect

Rob

[mhiggins]

well here is the first alluminum part I cut on my machine I was very happy with it it was only out about 2thou. I screwed up when I made the toolpath by selecting inside instead of outside edge for the path to cut it out. I cut it at 30ipm and took 0.030" passes very light but well worth the wait if you are wondering what it is it is a bearing block hope to upgrade all of the hdpe. oh ya I used a two flute upcut carbide endmill at 16000 rpm.

Did you use any kind of cutting fluid when you machined these?

[truman]

those ones are just mdf but for the alluminum I squirted a little wd40 as it cut works well.

Rob