[vcatalasan]

Finally got my X2 converted and made up the electronics also have limit switches on all axis ends. For some insane reason I just cant grasp the Z axis. I have the Ymin at 0 and Ymax set at -6 inches. I have it home'd switch at the top and whenever I load a gcode and try to run it the head on the graph is below the part that need to be cut. I think maybe my limit switch is incorrect as I tied all Y++, X++ and Z++ to pin 13 and the others.

Here is what it looks like as the graph of the part to be cut is not resting at the bottom of the table.

Thanks for your help

[sabastion]

[Quote]For some insane reason I just cant grasp the Z axis. I have the Ymin at 0 and Ymax set at -6 inches. I have it home'd switch at the top and whenever I load a gcode and try to run it the head on the graph is below the part that need to be cut.[Quote]
I tak it you mean zmin at 0 and zmax at -6"


do you have z wired backwards maybe?
Try entering z min 6" and zmax 0" and see if you get it to go in the direction you want.

Keep in mind I'm a newbie and may not have a clue what I'm talking about

[jeremy0203]

not sure exactly what your saying.

your z limit is at the top of its travel?

if so are you basing your heights in the program off the height of the z at its limit or are you zeroing at the surface of the piece.

also are you using negative z values in what i am guessing is one of the wizards you are using?

have you tried to run the program to see what it actually does instead of going off the image?

[vcatalasan]

Thanks for responding and got it figured out. It was one of the value being -6 then 0. The Z was always showing at the bottom even though its actually at home. Also played with the 3 setting that changed location and direction Z-axis Dir Low setting, Home Neg and Reverse check marks. One or two of the setting made it work. I was able to finally do a test run.

On another note, I had 2 conductor wires going to all them limit switches, if I had to do again I would have ran all the switches in series and only need to use one pin on the G540 controller, less wire mess to deal with. I see no reason at all for having separate pin on the G540 as the Mach3 can deal with it using the pin and port assignment. Is there any advantage to using separate port for home and limits?

[BoxRec]

On another note, I had 2 conductor wires going to all them limit switches, if I had to do again I would have ran all the switches in series and only need to use one pin on the G540 controller, less wire mess to deal with. I see no reason at all for having separate pin on the G540 as the Mach3 can deal with it using the pin and port assignment. Is there any advantage to using separate port for home and limits?

I can see how it's possible to wire up two series of switches, one for when you reach end of positive travel and one for negative travel. But with only one series how would the system know which way to back off to identify which axis was tripped ?

[rpovey]

Home switches need independent pins, Limit switches just trigger EStop so it doesn't matter.

[hoss2006]

All home and limit switches can be wired in series (Normally Closed switches) and be connected to one pin. Thats how I do it.
Projects2
Your home switch is also a limit switch just depends on how Mach is moving at the time.
If you are homing, it knows to back off and reset, if it's just jogging or feeding any tigger
will stop all movement.
Hoss

[photomankc]

Do them all in series and you save a lot of I/O but it means also that if something trips it's not easy to identify what exactly did it (in theory) because any one or any combination could be tripped, or stuck, and you can't tell which. When the machine homes then it will have to do it one axis at a time. In parallel then you use more I/O but the system can see which limit tripped exactly and it can home all axises at the same time. In reality it's probably going to be rather apparent which one tripped it and the sequential home process is not THAT long anyway.

With EMC and soft limits there is little real need for a positive limit sw since the machine will check the program for any exceeded travel and the motion planner checks again before each move. The only way to run into a limit is to run without homing or get into trouble and stall the stepper motor and then it gets out of sync enough to run into the edges even though it thinks it still inside the limits. Even if you do, steppers tend to stall out and won't often break things on the machine unless you gear them down for slow speed but gobs of torque or rapiding around at warp speed.

I imagine Mach3 is similar.

[hoss2006]

Mach homes one axis at a time with the z first.
I wouldn't want them all going at the same time, you could snap off a tool before the z got
raised enough out of harms way.
If a limit trips it's pretty easy to see which one is at the end of it's travel.
Diagnosing a false trigger would benefit from separate pins per switch but why waste
valuable inputs on a rarity.
Hoss

[photomankc]

Mach homes one axis at a time with the z first.
I wouldn't want them all going at the same time, you could snap off a tool before the z got
raised enough out of harms way.
If a limit trips it's pretty easy to see which one is at the end of it's travel.
Diagnosing a false trigger would benefit from separate pins per switch but why waste
valuable inputs on a rarity.
Hoss

That's a good point on the Z... wasn't thinking of that. I agree that given the usual scarcity of I/O and the infrequency of a multiple trigger or false trigger that it usually makes sense to wire them in series and only burn up a single I/O for limits and home for all.

I was planning on doing them in parallel because my electronics setup will have ample I/O to handle that and more. I'm pretty sure in EMC you can customize the homing sequence to just what you want (I have not looked at in depth yet) but I'll keep that in mind on homing Z by itself first. A long drill and tall fixture would really suck.

[vcatalasan]

All home and limit switches can be wired in series (Normally Closed switches) and be connected to one pin. Thats how I do it.
Projects2
Your home switch is also a limit switch just depends on how Mach is moving at the time.
If you are homing, it knows to back off and reset, if it's just jogging or feeding any tigger
will stop all movement.
Hoss

I have realized that we don't need 6 switches either. 3 switches would have worked for all 3 axis limits. You would mount the switch on the center travel and mount screws at the end of each limit to engage the switch. Duh! I have just started so everything is really new to me and if I new any better I would have done it this way and its much easier, plus troubleshooting 3 switches with a single conductor cant be that hard.

[LUCKY13]

Also you want to use N/C switches. This way if a wires breaks or comes loose, or if the switch goes bad the circuit will go open and stop the machine. If its setup as N/O then the computor doesnt know if anything has lost connection.


Jess

[vcatalasan]

I decided to rewire the limit switch and use only one pin on the G540.

Here it is before and after. BTW there is no difference in operation other than all the switches light up on the diagnostic page.

[vcatalasan]

Here are some pics of the switches, some i could not take cus it a bit hidden.

[vcatalasan]

And my first run on a foam.

I still need some more things to complete the process, need one of them quick change tool. The belt conversion and replacement way covers, using cardboard for now and someone else's idea about using a front cover was nice to use.

[vcatalasan]

Okay $1700+ later I can now cut foam! which I could have probably done using a butter knife.

Well at least it is no longer a $600 drill press. Hope to make more things in the future!