G540 and NPN Prox. Switch

[john-100]

Hi Nicolas

just looked at the video and its a capacitive sensor with an operating range of 1 to 25 mm

the n/c hall proximity switch that came with my tachometer module switches when the magnet is about 10 mm away
I expect your switches will be very similar but when you take for the gantry to stop as you say the gap has closed to 3mm or 1/8"

how about turning the proximity switch by 90 degrees so the magnet passes by end of the switch

John

[kolias]

Yes I could turn the switch 90 deg. but then it will be sticking to the side of the machine and prone to damage (that’s where the enclosures you suggested earlier comes handy).

I thought it was possible to add some electronics and make it adjustable. I remember I was reading about these prox switches and I saw something about adjustable but when I ordered them I forgot about the adjustable feature.

No problem, I will manage somehow but now I think the micro limit switches with the lever are much better and easier to install

[john-100]

Hi Nicolas

just found this-

LJ12A3-4-Z/BX DC 6-36V 200mA 3 Wire NPN NO 4mm Inductive Proximity Sensore Pulsante

it gives the detection distance of your switches as 4mm !!

how about putting the magnet on a spring mount and adjusting the switch position more to the right as seen in your photo - so the axis should stop sooner

now if the gantry does not stop in time , the magnet can be pushed back against the spring when the switch and magnet make contact

John

[kolias]

When you say “putting the magnet on a spring mount” which magnet are you referring John?

[john-100]

Hi Nicolas

existing magnet that operates the proximity switch

I can't make out from the photo how its mounted I guess its glued to the reverse side of the vertical part in the photo

John

[kolias]

Sorry John but as you know this is the first time I get involved with prox. switches

I have no magnet installed on my machine, I thought you are refering to the blue part at the front of the switch itself

[john-100]

Hi Nicolas

Sorry for the confusion
at 1:30 this morning I confused my self and forgot your proximity switches are inductive the type and not Hall switches like I have with the tachometer module that needs a magnet !!

if arranging the proximity switch for a metal flag to pass over the end of the switch
then a spring loaded plunger ( without the magnet !) could still be used to protect the switch from the occasional over travel

the data sheet I found -


does not indicate if its more sensitive to some metals than others
it may be worth testing it with pieces of steel , aluminium and brass

John

[kolias]

No problem at all John

I found an alternate way for the installation which will not damage the sensor if I have an overtravel and I will send you a picture when I’m done.

However I foreseen a problem with the Z axis due to the limited space available.

On the G540 is it possible to combine NPN sensors with micro switches (the ones with the lever)? These micro switches have 3 terminals (NO, NC, COM) and if it’s possible how do I wire them to the G540?

[john-100]

Hi Nocolas

you can wire the microswitch across the blue and black wire that the proximity sensors are connected to



John

[kolias]

That's very good news John, thanks

[kolias]

Hello John

I tried a setup as per post #32, method #1 but still the sensor must be a few millimetres away from my gantry to be activated which is too close for comfort. Looks like I will not use these prox. switches and that I will go back to micro switches. Luckily I have enough micro switches to finish my job

But for future projects are all NPN (NO) proximity switches similar? Perhaps there are other types which you have an adjustment on them to increase the sensing distance?

[Sadmeatball]

Hi Nicholas

im wondering did your method work by connecting

X + / X- / X Home / Z + / Z- to Pin 1
Y + / Y- / Y Home to Pin 2
A Home to Pin 3
Probe to Pin 4

I am currently building a CNC machine using Gecko G540 drive and stuck with the Wiring Proxymity switch problem ...

I hope you can help me ..

Thank you very much

Regards ...

Cakra Beddu

[kolias]

Sorry mate, I never used those prox switches as I found the distance to trigger the switch was very small, don’t remember but I think it was a few millimeters, and so I went to what I used before, the lever type. Simple and effective