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Home switches
« on: March 21, 2008, 12:04:11 AM »
I am going to wire my home switches  normally closed in seares , 3 switches , pin 12, lpt ground. Will this work or should I go another way? I do not have +5v on my board. Is it best to us shielded 22ga wire for wiring home switches? Sure could use some advise here, I have burnt one board, Stepmasternc screwed me out of one, Paid and did not receive !! >:( If this wire is what I should be using, where is the best place to buy??

Offline jimpinder

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Re: Home switches
« Reply #1 on: March 21, 2008, 05:18:09 AM »
You can wire home and limit switches either way.

You do not need a 5 volt supply. Inputs to your computer are pulled to 5 volts by internal resistors in any case.
You may start at one of the ground pins - 18 - 25, go to the first switch, go to the second switch, then the third switch and then to the computer input which you seem to say will be pin 12. (why 12 - what have you got on the others ?? - you may use 10,11,12,13 or 15).

If you wire the switches normally closed, then this will put a 0v on the input - which will be pulled to 5v when a switch is opened by the carriage. This method is preferred by some, because it means that if any wires come loose, then a fault will occur before your carriage hits the end of travel - but to Mach3 it does not matter,it will work either way.

In you Config/Ports and Pins - show all the homes (if you are doing them all) as Port 1, Pin12.  Do NOT tick "active low"

There is very little current in the circuit, so any thin wire will do - I use wire taken out of a an old 25 wire printer cable. It does not need to be shielded - but do not run it NEXT to stepper motor wires etc that have a lot of changing current. 


Not me driving the engine - I'm better looking.
Re: Home switches
« Reply #2 on: March 21, 2008, 01:27:55 PM »
Thanks Jimpinder...for your reply, I will wire my home switches in this way as you say. just to confirm,

 Ground from 18to25 to Z switch jump to Y switch , jump to X switch, then +5v back to pin 12 or any Input pin, correct?

The reason for wiring switches normally closed , I read it on one of the threads, an it sounded like the safest ! At this point I haven't wired them yet so I can go eather way?

I am only doing XYZ Home, should I enable X++ X-- and so on?

I will use printer cable wire for the home switches, just wandering if you can use solid copper wire very small, or would it brake with the movement?

At this point I haven't used any of my inputs, just picked 12 at random . I need to hook up my charge pump , e-stop , and the spindle inputs, will need the rest for these? Thanks again for yory HELP.

Offline Hood

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Re: Home switches
« Reply #3 on: March 21, 2008, 03:21:11 PM »
Yes you want to have all of the X, Y and Z options in Mach on Pin 12 including the Home switches, that way you dont need seperate homes.
 Personally I use shielded cables on anything that has 5V in it, the difference between Hi/Lo with 5v is small and any noise picked up can easily trigger them.
Hood

Offline jimpinder

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Re: Home switches
« Reply #4 on: March 21, 2008, 04:44:17 PM »
You have the idea - but not quite right.

You do not need any 5v supply - this is provided internally by the computer on pin 12

A quick diagram is provided.

As Hood says - you can shield the cable if you require - you can use solid copper if you wish - there should not be any movement - fasten the switch to the frame of the  mill and let the carriage operate it.

Hood also says you can , when you configure the switches, have them act as limit switches as well. This would be a good idea, you dont want the carriage to go beyond the switches or they will be damaged.
Not me driving the engine - I'm better looking.
Re: Home switches
« Reply #5 on: March 21, 2008, 07:11:28 PM »
I have the switches wired as you said, except i have them wired Z, X, Y, only ground wire to the end of the last one, and hot wire from there to pin 12. I am not getting 5v out of pin 12. I have checked pins 10,11,13,15, they have 5v.  Could I have blown pin 12 some how. As for the switches being solid to bed, they are loose on the screws. I will take care of that. When I shut down my machine I am getting ticking sound out of the charge pump, and it's not wired to the board yet. It sounds like a current pop maby. It also was tripping the switches with out hitting and said limit switch hit, maby  because there loose?  I'm trying guys stick with me!! :)
Re: Home switches
« Reply #6 on: March 21, 2008, 09:31:42 PM »
OK...the no +5v on pin12 in fixed, when I tested the port  for 5v i forgot to push the normally closed home switch, for -0v.  I now have shielded wire to put on the home switches tomorrow.

Next will be the spindle wiring on the board, would that be input 10,11,15,??  ground com. on board??  Does this sound right?

Offline jimpinder

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Re: Home switches
« Reply #7 on: March 22, 2008, 04:32:35 AM »
Get the home switches done and configured.

What are you wanting to do with the spindle - do you mean an index counter to check the RPM - if so that can use any input wire and be configured the same way as the home switches.
Not me driving the engine - I'm better looking.
Re: Home switches
« Reply #8 on: March 22, 2008, 01:38:52 PM »
Yes you are right..Getting a head of my self !!  Will make sure the switches all work before moving on. That's what i want , slap my hand if I get ahead of my self. ;)

I was going to transfer the rest of the wires from the old board , and just had 3 wires left from the Charge pump, one spindle wire input on old board and one wire charge pump on input pin, and a ground from charge pump on old board ? I will worry about these later !!
Re: Home switches
« Reply #9 on: March 22, 2008, 09:09:31 PM »
Have all 3 switches wired in series X-Y-Z , Gd to X switch then to Y switch then to Z switch and +5v to pin 12... enabled all limits and homes port 1, pin 12, Active low setting is RED Check... it says triped limit switch...All led's in Diagnostics are lit....I do not know what to do???  I used shielded wire grounded the shielding copper wire to the bed and have all switchees fastened solid to the bed...any ideas??