[Burn]

Hey Guys,

I will probably get my Taig mill within 3 months, and I was looking into these:
http://www.hightechsystemsllc.com/in...s/Page1220.htm

I understand what the limit switches do, what do the Home switches do?

Also, I am using the Xylotex 4-axis control board. How would I go about hooking these up to the board...Can I?

Thanks a bunch guys, I appreciate it.

Burn

[GlenBA]

Home switches tell the CNC controller where machine Zero is for the X, Y, and Z. I got the ones from Hightech, and they mount pretty easy. I used this diagram from Xylotex to hook them up. The one for the Y Axis has to be hooked up opposite to the X and Z, because the switch is always clicked until it is home.

[Burn]

Thanks

Okay, so if I wanted to do limit switches, are they hooked up in the same place, just configured differently in Mach3?

[GlenBA]

Thanks

Okay, so if I wanted to do limit switches, are they hooked up in the same place, just configured differently in Mach3?

Mach3 can share switches. So the Home switches can also be the limit switches, if they are positioned at the end of the travel.

The other 3 limit switches are usually hooked in series and closed when not tripped, that avoids having to have to use 3 inputs. Instead you use 1 pin, and any of the switches that break the circuit will cause Mach3 to register a limit.

Also, remember to always hook up limit switches so that when the trip it is an open circuit, that way if a wire breaks you will know it when it breaks, instead of when the switch trips and does not register in Mach3.

[Burn]

Mach3 can share switches. So the Home switches can also be the limit switches, if they are positioned at the end of the travel.

The other 3 limit switches are usually hooked in series and closed when not tripped, that avoids having to have to use 3 inputs. Instead you use 1 pin, and any of the switches that break the circuit will cause Mach3 to register a limit.

Also, remember to always hook up limit switches so that when the trip it is an open circuit, that way if a wire breaks you will know it when it breaks, instead of when the switch trips and does not register in Mach3.

Okay, so I would wire them up in series, that way if a wire breaks it sets off the limit?

Thanks again.

[GlenBA]

Okay, so I would wire them up in series, that way if a wire breaks it sets off the limit?

Thanks again.

Yes, here's the diagram from Xylotex on hooking homing switches up in series. You'd hook them up the same way, just use them as limit switches instead.

[Burn]

Okay, so would I need 2 sets of limit switches for both ends of travel? All the way left and all the way right, in the case of the X axis, and all the way in and out for the y, and up and down for the Z?

[GlenBA]

Okay, so would I need 2 sets of limit switches for both ends of travel? All the way left and all the way right, in the case of the X axis, and all the way in and out for the y, and up and down for the Z?

No limit switch for the Z, your tool will be cutting the table long before you've hit the end of the Z travel going down.

Home switches are very useful if your going to be using offsets like G54, G55, G56 and so on for job setups. Every time you start your machine you can zero it out using the home switches, then all your offsets are set up because you set their values from machine zero or home position. The limit switches are a little less useful as you can set up soft limits in Mach3, so the machine will stop if your code says to move beyond the machine envelope. Of course, this won't help if the the steppers go berserk.

[Burn]

Well, it looks like I may be going servo from IMservice. Thanks for the pointer on the Z limit.

[TMaster]

Im in the process of hooking up 3 home switches on my Taig.
Durring normal operation is the curcuit closed having the voltage/reistance though the wiring and when it gets to the home position the switch opens so there is no circuit?
Or is The other way around where The circuit is open durring normal operation, and when it gets to the home positions the switch make the circuit closed/powered?

VCC and GND terminals on the Xylotex board with the 10k ohm resitors? I have the newer 4 axis board with P pins labeled.

Im going to be using the X home, and Y home, Z home, selections in mach3. Do i activate the Active low buttons too?

This is confusing. I need a a total made diagram. lol

[GlenBA]

Im in the process of hooking up 3 home switches on my Taig.
Durring normal operation is the curcuit closed having the voltage/reistance though the wiring and when it gets to the home position the switch opens so there is no circuit?

Yes, that way if a wire breaks it will trip Mach3 and you'll know before the machine crashes into the end of the axis.

Or is The other way around where The circuit is open durring normal operation, and when it gets to the home positions the switch make the circuit closed/powered?

VCC and GND terminals on the Xylotex board with the 10k ohm resitors? I have the newer 4 axis board with P pins labeled.

Im going to be using the X home, and Y home, Z home, selections in mach3. Do i activate the Active low buttons too?

The terminal block with VCC and GND, not the one with VBB and GND.

According to the "Ports and Pins" configuration screen for "Input Signals", 10-13 and 15 are inputs. I believe it's active high, but you'll be able to see in the Diagnostics window for Mach when the switch is active.

This is confusing. I need a a total made diagram. lol

[TMaster]

wow, thanks for clearing those things up for me. I only see active lows in the mach3 inputs.



When i have the active lows checked, the diagnostics screen shows everything normal. But when they are unchecked the diagnostic screen shows 3 of the homes lit up. I dont have anything hooked up yet though. I'm sure ill figure it out when i get it all wired up. I already have the swtiches mounted so they click when they dial goes to 0.

[GlenBA]

Active low means when there is a logical false, or 0, or an electrical GND, and triggers if this is true. Active high is the opposite, logical true, or 1, or 5+ on the line, and trigger when this is true.

When you have nothing connected to the pin you will get an ambiguous, or floating value, it may be high or low, but mostly since it's below the logical true value it usually comes out as 0. Therefore when you switched the pin to active low, it looked at the value at that pin and said, It's a 0, must be one, and turned on the light.

I've connected my switches on the X and Z axis's to the "Normally Closed" or NC terminal of the switch, and for the Y axis, to the "Normally Open" or NO, terminal. The is because the X and Z trip when switch is pushed, opening the NC part of the switch circuit, but the Y axis trips when switch is released, opening the NO part of the circuit. Here's a picture of a switch circuit that might help explain my lame attempt to describe NO and NC in a switch.

[Ninhil]

I am curious as to what switches to use. Like a brand or product to use.

Also, where do you mount the homing switches?

I feel that I wont bother with limit switches since the software like mach and mastercam can have the limits proggramed into them.


Thank you,

Brandon

[TMaster]

Limit switches are the best thing I ever did to my taig!!!

I do run mach3 but the programed limits only work so well, they are crap if your mill gets off from breaking a tool, having the wrong offset and anything thats makes the stepper motors stall. Then it takes forever to find the exact home spot.

I dont even run software limits anymore because I have the real limit switches. The great thing about them is you can always go back to the exact home position no matter what happens with just a push of a button in mach3. This is a must have when your making a lot of the same parts that have to be all equal and also if your using fixture plates. You dont even have to jog the machine back to home after your done. You can turn off the PC whenever you want and when you want to get back to home, you just press the ref all home button!

The roller lever switches a real cheap from radioshack they only cost $2.69 each. Then the wiring and resistors is cheap too.

Heres a little video of the Y and X limit switches in action. I'll try and get some picks of the Z axis.

"save" please.
http://www.acceleratedrc.com/pictures/Taig_limit.wmv