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bfgstew

• 105
• DOH!!!!!!!
Re: Limit switch issues
« Reply #90 on: December 27, 2015, 11:06:06 AM »

MuskokaMike

• 64
Re: Limit switch issues
« Reply #91 on: December 27, 2015, 11:29:25 AM »
If you're interested, I can explain

a) Why, after a limit has been hit, there is good reason why Mach3 allows a careless user to jog or move further onto the tripped limit.
b) why, it is a perfectly reasonable option to have a machine set to home to back left rather than front left.
c) why you most likely don't need to re-wire anything or move any switches on your machine and yet still have it do whatever you like.

a) Mach3 was designed to be fully functional with just ONE parallel port. It therefore has just 5 inputs. With just ONE input you can have fully functional limit protection AND homing.

How many inputs do you suppose you'd have to sacrifice just in order for Mach3 to prevent a careless user from jogging the wrong way after a limit trip?

b) Using a 3 axis setup as an example, home does not have to be 0,0,0. It can be any coordinate you like. Having it at the back means on an X gantry machine the gantry is not obscuring the table.

c) Limits can be wired series where they use just one input or in parallel where they can use as many inputs as you have switches if you so choose. Is there any point in the latter? absolutely none. Functionality will be identical.

However you can also use some of those switches to double as homing switches. If you stick with series, all will work just fine but homing will be done sequentially. If you wire parallel then you can choose to set up so axes home concurrently.

1)that doesn't explain why a user would want to move one or more of their axis past the limit switch where by doing so, they will damage their machine.
2)but your "home" should be 0,0,0 on the table, not (in my case) 0,48,0. Once zero'd in, you can move the gantry anywhere you like.
3) funny, mine are wired in parallel and yet home consecutively.....if I understood why you write, they should all home at the same time.....

My reason for wanting my home at 0,0,0 is because during some 3D long program runs (I have some that take upwards of 12 hours) occasionally a problem will occur and I'll lose "home"....to start machining a 3D items from scratch to reestablish zero is crazy. Re-homing my machine manually (to locate the 3 axis on one spot) more likely than not will result in the 3D item being machined to have parts of it slightly offset than the rest....for eg: if I'm cutting a nose of an animal, if I'm .01 of an inch off, instead of being smooth, the nose bottom and top will be misaligned.

One of the things that occurs is, where I live, the electrical grid is as fragile as a robin's egg. Whenever it is raining, windy, snowing, (and sometimes) sunny, or just because it's thursday, the power will flicker...when it does, even for a millisecond, that causes the machine, and mach3 to become out of sync.....it's gotta so bad I have to check the weather report if I have to run a long highly detailed item...if it's windy? I don't run. If it's snowing? I don't run often times I HAVE to run it on that particular day (due to scheduling) so I'll wait and run it at 12 am after the storm or whatever has passed.....

Yes, I can re-zero manually and it's pretty simple if you're using a 30 deg v engraving bit...but if you're using a ball mill, or a 1/4" 2 flute roughing bit, it could take an hour of trial and error to get it back close, then after the program run is over, 9 times out of 10, alignment is off....

MuskokaMike

• 64
Re: Limit switch issues
« Reply #92 on: December 27, 2015, 11:39:29 AM »
You can't disable the Estop, or Mach3 will not run. Just set it to any unused input pin number, and toggle the active low setting if it doesn't let you reset.

Quote
btw: I just enabled my limit switches, and home switches...now my x axis tries to home to the right (+ side) instead of the home switch on the left (- side) and it doesn't trip the limit switch when it does, it just grinds into the rail.....

when I reverse the homing, then when I jog to the plus, (right) it goes left and vice versa....

I get the abnormal condition light flashing and on the DROs it says my "head" is at -51 inches on a 24" table

This is what happens when you change too many things at one time.

First, you get the machine to move in the correct direction. If you jog to the right, do the DRO's count up (increase). If so, then Mach3 is correct. But if the machine is moving left, go to Config > Homing/Limits and check the reverse box to change direction.
Once it moves in the correct direction, then home the X axis. If it moves the wrong way, toggle the "Home Neg" setting.

Disregard the Abnormal Condition. It's the absolutely worst feature in Mach3.  When everything is working the way you want it to, go to the Operator menu, and click "Set Normal Condition". Even better is to remove it from the screen with a screen editor.

There's nothing wrong with the X home switch at the positive end of travel. I have mine setup that way, so that when the machine homes, the gantry is clear of the table so I can setup my parts.
What you want to do, though, is go to Config > Homing/Limits and enter the actual switch position in the Home Offset box. This value is what mach3 sets the DRO's to when you home. So, if you set it to 45, your X zero will be at the left end of the table. When you home, the X DRO will be set to 45.

So just to confirm, Mach3, in all it's glory, doesn't allow you to have your home at ACTUALLY 0? That it is factory set at +24 (in my case) which is the far right of the table? that I have to trick it to think that X0 by putting in a positive number to get it to go to zero? You see, this is counterintuitive to me....if I want my x axis to move to zero, I should be able to put zero in my home position and to get it to be there, I feel I should have to put in a NEGATIVE number (if mach is saying dammit jim, 0 is at +24....).....to get it to be 0....

bfgstew

• 105
• DOH!!!!!!!
Re: Limit switch issues
« Reply #93 on: December 27, 2015, 11:57:09 AM »
You can have home werever you want it, if you want it mid travel, that's fine, you just need to tell Mach3 were your zero is, not Mach3 telling you were it should be. You define your parameters how you want them, how you want your machine to behave, you just need to give Mach3 all the details and it will work how you want it.
Have you thought about a little generator set to power the workshop if your supply is as fragile as that, for a few hundred \$ it should pay for itself very quickly....................just a thought.

bfgstew

• 105
• DOH!!!!!!!
Re: Limit switch issues
« Reply #94 on: December 27, 2015, 12:08:41 PM »
If I snap a tool during a run, I simply stop the program, note what line Gcode the break happened, press ref home all, fit a new tool, re zero the tool height, set Gcode to the line of Gcode needed and press run from here, takes about 5 minutes and am back up and running with no problem. As long as Mach3 has all the info it will do want you want it to.

MuskokaMike

• 64
Re: Limit switch issues
« Reply #95 on: December 27, 2015, 12:11:28 PM »
You can have home werever you want it, if you want it mid travel, that's fine, you just need to tell Mach3 were your zero is, not Mach3 telling you were it should be. You define your parameters how you want them, how you want your machine to behave, you just need to give Mach3 all the details and it will work how you want it.
Have you thought about a little generator set to power the workshop if your supply is as fragile as that, for a few hundred \$ it should pay for itself very quickly....................just a thought.

I had one when I lived off the beaten path out of town but since I had to move into town, I'd get noise complaints in about 10 minutes....plus gennie produced electricity isn't the best for computers etc....you'd need an inverter gennie and those are quite pricey....(this is another area I'm not 100% clear on but from what I've read, and gathered from "pros" that gennie electricity is quite noisy and can cause major issues with electronics)....

You're not the first person to say this...in fact, many residents continually ask our politicians about why doesn't the town get our own source of electricity since being on the grid is VERY expensive and HIGHLY unstable.....we're constantly poo pooed. You see, where we are, we get a "delivery charge" tacked on our bill which is equal to, or often higher than the electricity we use.....

MuskokaMike

• 64
Re: Limit switch issues
« Reply #96 on: December 27, 2015, 12:18:52 PM »
If I snap a tool during a run, I simply stop the program, note what line Gcode the break happened, press ref home all, fit a new tool, re zero the tool height, set Gcode to the line of Gcode needed and press run from here, takes about 5 minutes and am back up and running with no problem. As long as Mach3 has all the info it will do want you want it to.

yeah, that is exactly what I want to be able to do, and it is only logical to be able to do that...

Now, here is another design flaw in my CNC....the builder, in his infinite wisdom, designed it so that under NO circumstances would you break a tool. He has built into the machine flexibility so that the machine will kick off axis etc instead of damaging a tool...even though I pay \$2.00 for my ball ends and \$3.00 for my straight cutters...it is so bad that when cutting pine, with an 1/8" straight bit, with 1/8" DOC the z axis is thrown off 90 degrees and results in patterning in the piece.....ludicrous (which is why I'm going to be replacing all these parts with something, I dunno, that stays straight plumb and true.....I mean, he even used an aluminum rod to transfer the x axis power to the other side of the table. It flexes under load and causes both sides to be out of alignment slightly....took me quite a while to figure out why I can't cut perfect circles....it's because it is mis-shapened dramatically as the axis rotate around the circle....DOH

edit: and the kicker is, I still break tools.....and the bigger kicker is: the use of plastic isn't that big of a cost saver....aluminum would cost maybe \$50 more for the entire machine. Hell, I've recently learned how to make aluminum castings and I could cast all the parts for under \$20.00....
« Last Edit: December 27, 2015, 12:28:00 PM by MuskokaMike »

Tweakie.CNC

• 8,705
• Super Kitty
Re: Limit switch issues
« Reply #97 on: December 27, 2015, 12:27:03 PM »
Hi Mike,

You say your switches are wired in parallel and your .xml shows the switches (including EStop) configured as active High. This being the case your switches will be connected as normally open (N.O.) – check your EStop switch to make sure it is open circuit in the run position (they are normally closed circuit in the run position) otherwise it will not work with this configuration (which may explain why it has not been working and no port# had been allocated to it).

Tweakie.
KEEP SAFE !

ger21

• 6,289
Re: Limit switch issues
« Reply #98 on: December 27, 2015, 12:27:35 PM »
Quote
1)that doesn't explain why a user would want to move one or more of their axis past the limit switch where by doing so, they will damage their machine.

The answer is it would require a system with a lot more inputs than Mach3 was designed with. If Mach3 was designed to do what you're asking for, it's price would put it out of reach of many of it's users.
It is what it is, let it go.

Quote
2)but your "home" should be 0,0,0 on the table, not (in my case) 0,48,0. Once zero'd in, you can move the gantry anywhere you like.

No, Home is where your home switches are. 0,0,0 is your origin. Two different things.
Quote
So just to confirm, Mach3, in all it's glory, doesn't allow you to have your home at ACTUALLY 0? That it is factory set at +24 (in my case) which is the far right of the table?

No, Mach3 isn't "Factory set" for anything. The person that sold you the machine configured it that way.
As was already mentioned, Mach3 let's you call "Home" anywhere you want.

Quote
My reason for wanting my home at 0,0,0 is because during some 3D long program runs (I have some that take upwards of 12 hours) occasionally a problem will occur and I'll lose "home"....to start machining a 3D items from scratch to reestablish zero is crazy. Re-homing my machine manually (to locate the 3 axis on one spot) more likely than not will result in the 3D item being machined to have parts of it slightly offset than the rest....for eg: if I'm cutting a nose of an animal, if I'm .01 of an inch off, instead of being smooth, the nose bottom and top will be misaligned.

After you set your 0,0,0 position, go to the Offsets screen and Save the offsets.
If your power goes out, home the machine, and your 0,0,0 position should be right where it was before.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html

ger21

• 6,289
Re: Limit switch issues
« Reply #99 on: December 27, 2015, 12:29:17 PM »
Quote
Now, here is another design flaw in my CNC....the builder, in his infinite wisdom, designed it so that under NO circumstances would you break a tool. He has built into the machine flexibility so that the machine will kick off axis etc instead of damaging a tool

A more flexible machine can break tools easier than a rigid machine, by allowing a tool to pull itself into the workpiece until it snaps.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html