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View Full Version : Uniport and limit switches.



D-man
13-02-2012, 10:00 AM
Hey guys, im having a problem with wiring my limit switches up to the uniport.

Do any of you good guys have a wiring diagram which i could go off or possibly give me a fool proof option :whistling:

D-man
13-02-2012, 10:02 AM
sorry maybe i should mention i would like the switches to act as home switches also. i had one test switch hooked up and homed the machine pressed the switch and it backed off but didnt stop until i let off the switch

Robin Hewitt
13-02-2012, 11:11 AM
I've been thinking about changing my limit switches, I'm very interested by RS pn: 171-3808, a slotted optical flag switch.

Here's a data sheet: http://docs-europe.electrocomponents.com/webdocs/0028/0900766b80028ba3.pdf

It switches with a max force of 1.5gms, they all agree with each other plus minus 3 degrees and it has a good overtravel (infinite if you get the actuator angles right).

What they don't tell you is the hysteresis and repeatability for an individual part. Even without the benefit of a Schmitt there is a distinct possibility it could be freakin' amazing as a positioning switch.

I will order some today and report back.

D-man
13-02-2012, 11:56 AM
so did you just run without the switches? im running mine without but just want that little bit extra from the machine


im using a uniport v2 i,ll have to fish out what came with it.

it was jonathan on here that wired mine but for some reason we could never get more than 3 switches to work when all were wired none would work.

D-man
13-02-2012, 11:56 AM
They do look interesting,!!


I've been thinking about changing my limit switches, I'm very interested by RS pn: 171-3808, a slotted optical flag switch.

Here's a data sheet: http://docs-europe.electrocomponents.com/webdocs/0028/0900766b80028ba3.pdf

It switches with a max force of 1.5gms, they all agree with each other plus minus 3 degrees and it has a good overtravel (infinite if you get the actuator angles right).

What they don't tell you is the hysteresis and repeatability for an individual part. Even without the benefit of a Schmitt there is a distinct possibility it could be freakin' amazing as a positioning switch.

I will order some today and report back.

D-man
13-02-2012, 12:49 PM
Double post

JAZZCNC
13-02-2012, 05:52 PM
i had one test switch hooked up and homed the machine pressed the switch and it backed off but didnt stop until i let off the switch

Thats how home switches are supposed to work.! They hit the switch which triggers the signal state then reverse until the switch releases's and signal changes back to it's original state. Depending how you have them wired IE Normally open (NO) or Normally closed(NC) the signal will go Hi or Low the control software(Mach etc) just watch's for this change.

Wire them NC for safe operation then if a wire breaks or comes lose then the signals lost and machine stops.

The wiring is easy just wire them in series IE + - + - + - + -

D-man
13-02-2012, 06:42 PM
cheers JAZZ, my switches only have 1,2,3 on them would 1 be the positive?

D-man
13-02-2012, 07:07 PM
Do i have the right idea with this?

m.marino
13-02-2012, 08:13 PM
Robin,

I got family not to far from there. Might see if they have counter service and get a group order together if they do as that looks like a very nice set up and with just a little bit of shielding from FOD would be a very dependable switch.

Michael

JAZZCNC
13-02-2012, 09:29 PM
Do i have the right idea with this?

Yes but you can if you want to save inputs put them all on the same input X,Y & Z Axis.

The switch's 3 terminals would go something like this:
Terminal 1 = input
Terminal 2= output normaly closed or Terminal 3= output normally open.
To check which is which just use a multimeter set to continuity then probe between pin 1 and any of the others, one should show continuity when switch is NOT pressed, this is the NC switch, the other will show no continiuty untill switch IS pressed. This the NC switch.

Personally I would wire all the limits in series X,Y & Z to 1 input and the home switch's to another.

D-man
13-02-2012, 10:08 PM
That's awesome jazz thanks for the reply. I will wire them to 2 separate imputs. I've been thinking about these Honeywell micro switches ps these little switches seem very flimsy

JAZZCNC
13-02-2012, 10:21 PM
That's awesome jazz thanks for the reply. I will wire them to 2 separate imputs. I've been thinking about these Honeywell micro switches ps these little switches seem very flimsy

If they are the little Micro switch type they work resonably ok and are fine for limit switch's because you hardly (Or should) ever use them. But for home switch's I suggest you use better quality switchs because they get a lot of use. The cheap micro switch one's tend to bend the lever so not very good for repeatabilty.
I have honeywell switch's on my homes and they are spot on and have never failed me plus give good repeatabilty. There are better switch's regards repeatabilty etc but I like the honeywells because they are very robust and just work giving good enough repeatabilty for my needs.

Robin Hewitt
13-02-2012, 10:26 PM
The only snag with using series switches comes when you switch on with either active and try to home it.

It doesn't have a clue which way to go :naughty:

JAZZCNC
13-02-2012, 10:37 PM
The only snag with using series switches comes when you switch on with either active and try to home it.

It doesn't have a clue which way to go :naughty:

Yep thats why it's good practice to always jog away before homing.!