[riche543]

Sorry meant this photo


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[john-100]

Hi riche543 ,

what supply voltage are you using for the hall switches , 5 or 12V?
and how many switches are you connecting to one G540 input

as the G540 input is connected to +12V via a resistor and the optoisolators
LED
I'd use a 12V supply and increase the value of the resistor in series with your
LED indicator to 1800 or 2200 ohms (1K8 or 2K2 )

with a 5V supply
when the hall switch is off ,the voltage across the LED indicator will be reversed
as the anode is connected to +5v but the cathode will be about +10V as measured at the G540's input terminal
(+12V from the G540 less the 2V or so dropped across the optoisolator's LED)

depending on the reverse breakdown voltage of your LED's
you may need to connect a diode in series with the LED

to connect two more switches , with individual LED indicators , to one G540 input
connect the output of each switch via a separate diode as in the 2nd diagram

John

[riche543]

Hi John
Thanks for reply
Yes I was using +5v from a pc power supply. My switches are wired in parallel , I would only like too use one input on g540, as I will have touch probe & superpid connecting later. I'm a bit of a noob when trying too work out these things, is there anyway to salvage the switches that are already epoxyed in the cases. All LEDs would also come on at the same time which I guess is it due to parallel wiring , that's not really a problem . If I need the 1n4148 diode I can easily get them from jaycar electronics store here in aus & redo some new switches , just need dummy's guide too wiring , if someone stood next too me & showed me how to do most things I would be able to understand better. Thanks again John.
Cheers
Riche.


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[riche543]

If I were to use this diagram with led would I use +12v or +5v. & just to be sure the - from switch would go to ground on g540 & out would go to say pin 1 on g540 ?
Cheers
Riche.



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[john-100]

Hi Riche ,

diodes to isolate the switch outputs from each other can be added to your
switch output wires

you may find this all you need to do

it depends on the current that will flow from the G540 input terminal to the
+5V supply when all the switches are off

I think the 560ohm LED current limiting resistor is too small a resistance the use a +12V supply
for your hall switches

you could add a transistor and a resistor to the diode "OR" gate


John

PS yes the diagram in post 664 is for use with a 12V supply
the resistor to limit the LED current has been increased from 560 ohms to 2K2
the -12V supply is connected to the G540 terminal 12

[riche543]

Thanks again john for your reply,
so went & got a pack of diodes the same as you mentioned & some 2k2 resistors. So should i use +12v instead of +5v this wont be a problem to do so. Also had to order some more SS441A sensors from farnell/element14.
What a game getting these, they told me that they have to come from USA but there waiting on stock so i wouldnt recive them till end of june.
on the site they have 2 types of SS441A sensors could someone tell me if i can use the ones they have in stock heres the link. Search Results | element14 Australia

Cheers
Riche.

[john-100]

Hi Riche ,

I don't think the limit switches you have made will be OK run from a 12V supply
the LED current will be near to the limit for the SS441

while the diodes connecting the output will solve the problem of all LEDs
switching on together
I expect you will need the NPN transistor to ensure the optoisolator in the
G540 switches off

a 12V version of Romans circuit with the added diode will be simpler

John

[riche543]

Thanks John
Please just confirm I can use this diagram
With +12v & is there anything I need to do at g540 end what is the npn transistor.
Thank you.
Riche.


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[john-100]

Hi Riche ,

either version of the limit switch in your last post will be OK
when used with a 12V supply


the NPN transistor is the 2N2222 in the circuit diagram ,in post 655
( it can be virtually any small NPN transistor - eg BC107)
its only needed to connect the original limit switches you have built to the G540 input
if the optoisolator in the G540 proves to be too sensitive
and is turned on by the current that will flow from the G540's +12v
to your limit switch +5v supply when all the limit switches are off

John

[riche543]

Thanks John
Really appreciated cheers.
New halls arrived this morning so guess I will have soldering iron out tonight.
Cheers.


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[john-100]

Hi Riche ,

thats quick , I thought they would only arrive next month
now you don't have to adapt the switches you have all ready made
before you can finish testing your machine

I expect you will test the new limit switches before they are set in epoxy


John

[riche543]

Yep will check before epoxy long story rgd the halls & ordering that's why I asked the difference between the 2 types . In the end I phoned & said looks like they have stock of ss441 in uk can't you get them from there. It seems same product has different part number from uk site to au site. Crazy so I placed order over phone & girl said no problem you will see them tomorrow ?.
So don't no why they have 2 types of ss411 looks like typo on there site , & think they have corrected it .



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[john-100]

Hi Riche ,

I've just had another look at the two Hall switches
the only difference I can see is one is RoHS compliant


John

[riche543]

Hi John
So when I went to order second time round I just went too my previous order which weren't in stock , wish I would have known that they are basically the same , would have saved loads of 1300 numbers, never mind got them now , just cut out some new cases for switches & magnets,


Cheers
Riche.


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[john-100]

Hi Riche ,

they look great , made to measure for each axis

John

[riche543]

Hi all
Heres a few pics & link to video showing the hall sensors mounted & working great on my new cnc, Thanks to Roman for starting this topic off john for making things alot clearer for me, & everyone else who helped me with my nooby questions
Heres Link for video : [ame=http://www.youtube.com/watch?v=IMpSQMQ3U00]CNC Hall Sensor Limit/Home Switches - YouTube[/ame]

Cheers all
Riche :cheers:

[CptanPanic]

I am thinking of going with just the Hamlin sensors, but what was the consensus on best magnet to use?

[Al_The_Man]

My experience with Hamlin (reed type) is you can use either the small bar magnet they supply, or will operate with a small powerful button magnet also.
Al.

[john-100]

Hi Riche ,


nice to see its all working
a great video demonstrating Mach 3 homing and your latest hall switches in action.
positive proof hall switches with led indicators can be connected to a single
G540 input

theres no way you can miss the blue LED's !

John

[harryn]

Thanks for posting all of this info on hall switch sensors.