Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: nobby on February 02, 2023, 05:11:26 PM
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hello i am stuck, have these
(https://i.ebayimg.com/images/g/o4EAAOSwltBhrnbD/s-l1600.jpg)
data sheet - i think is
https://datasheet.octopart.com/GP1A05AJ000F-Sharp-Microelectronics-datasheet-7570727.pdf
3 wires
looking down on it from the top pin
1
2
3
pin 1 Vcc - dont understand = voltage cc
pin 2 gnd = ground, ?
pin 3 Vout = voltage out ?
i cant give it 24v
am i connecting it to mach on limits X++ and X--
is it not possible yo use them
i have them on each end of each axis
itching to play with me new toy but buggered the last one crashing the x home!!
sorry
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on my controller
i have 12 volt out
ground
and the input
i think
i think i get it
pin 1 12 volt in
pin 2 to ground on controller board
pin 3 is the input pin out of switch - to x++ = = == x++ means either way of x axis up or down, x-- the otehr way and the other switch
so i have 6 ground wires going in
or thats how it would work with a proximetry switch
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oh - so
the light beam is constantly on when not home.
12v + and ground
when the beam is cut
the input gets triggered
set mach to active high
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Hi,
according to the data sheet that is a 5VDC device with an absolute max of 10VDC. If you've applied 12V its probably toast.
Craig
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Agree with Craig and its not something that I would use for a proximity or limit switch.
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Hi,
I would be happy enough to use an optical switch for a Limit switch but would not use one for a Home switch.
Of course an optical switch used for any purpose is subject to chips or coolant getting in there and obstructing the phototransistor.
I would presume that anyone using such a device has already thought that through and judged it not limiting.
Limit switches are obviously mounted at the end of travel and a little inaccuracy, say 0.5mm either way in it's detection point
would be fine, and therefore I would regard opto-siwtches as perfectly adequate, with the proviso above.
A Home switch is all about repeatability and for that purpose I would not use an opto-switch.
As you know Mach when homing travels toward a Home switch and on detection of a switch activation, decelerates to a stop, and then
backs up until the switch de-activates whereon it References the axis. The repeatability then depends very much on the hysteresis of the switch,
that is to say the difference (in distance) between when the switch activates and when it backs up and de-activates.
An opto-switch activates as the interrupt blade advances and partially obscures the light beam entering the phototransistor. Let's assume the
activation occurs at 50% obscuration. Now when the axis reverses when does the switch de-activate...at the same 50%, or more, or less?.
The specifications of opto-switches do not include any hysteresis measurement.
I like Omron (or equivalent from other manufacturers) roller plunger snap action microswitches. They have a well-defined and thereby repeatable switch
activation point and more importantly a defined and repeatable de-activation point and the associated hysteresis, 0.05mm. I have used these as Home switches
on my first mini-mill and more recently both as Limit and Home switches on my new mill. I regularly get better than 0.02mm repeatability without
recourse to Index Homing.
https://nz.element14.com/omron-industrial-automation/z-15gq22-b/micro-sw-roller-plunger-spdt-15a/dp/1500340?st=snap%20action%20microswitch (https://nz.element14.com/omron-industrial-automation/z-15gq22-b/micro-sw-roller-plunger-spdt-15a/dp/1500340?st=snap%20action%20microswitch)
Craig
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I have done measurements on opto interruptors for clocks and Berth Boman for home switches. See:
http://vinland.com/Opto-Interrupter.html
And I attach an article that I wrote for a horological publication.
Bottom line: Boman found they worked very well and my measurements confirm if you use the right type.
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my 25 year old little mill uses them in a stock set up
i just don't know how to wire them
i think i get it now
12v one side
ground the other
middle wire-once tripped to mach 3
i still dont get if both limit switches on the same axis go to one input
due to if one is tripped the other one cannot be
homing direction
just use a limit switches and not home switches
or use them as home switches?
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Hi,
check on the specs, what I can find of them is that they are 5V devices, you wire them to 12VDC and you'll blow them up.
They can be used as either, or both, Homing and Limit switches, although my preference is for other than Homing switches, not withstanding that they work.
Craig
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understood
my only output on my breakout controller for limits switches is 12v
these will not work
just cobble in some micro switches
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https://docs.rs-online.com/82f4/0900766b812c8e16.pdf
10v
not worth the risk?
pardon my ignorance, but i dont undestand 10v in and 28v out
?
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its all a bit nice and stock with them
hmm
its a lovely machine, i have already bodged the motors on....
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pardon my ignorance, but i dont undestand 10v in and 28v out
The input voltage powers the photosensor. The maximum voltage is 10V. However 5V is all it requires.
The output uses an open collector transistor that acts like a normally open contact to ground, just like a mechanical switch. The maximum voltage it can withstand is 28V.
There are many low cost voltage regulators on eBay, Here is one example.
https://www.ebay.com/itm/403714437758?
You can use it to reduce your 12V to 5V for supplying the photo sensor.
This one's output is set by two areas marked A and B where you blob two pads together with solder.
There is a chart to show you how to set the voltage. For 5V there's no blob on A and a blob on B.
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hello
i have six of them 2 on each axis
can i get one of these
(https://i.ebayimg.com/images/g/WrQAAOSwotdjscUp/s-l1600.jpg)
12v in red to 12v on nvem breakout board, black to ground
5v 3a out
yellow to pin 1 vcc on all 6 sensors
black to ground on all six sensors
then simply take vcc out
x axis x++ and x--
y axis y++ and y--
z axis z++ and y--
in mach have the same pin for both switches on the same axis
send it to home whichever way
?
thanks
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thinking about it, i crashed my last machine a lot on soft limits - not having any travel after the switch
rookie mistake I hasten to make again
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Yes you can power all the sensors with one supply, its 3A output is enough for 100 30mA sensors.
then simply take vcc out
x axis x++ and x--
y axis y++ and y--
z axis z++ and y--
I'm not sure what you mean by vcc out, do you mean the output of the sensor? It's not Vcc, The output just makes a connection to ground when on.
You can connect two of these outputs to one input. The input needs to be the type that works with a switch contact to ground
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ahh
so there is no ground for it as its used to step the 12 volts down to 5
?
so it is impossible
-great
2 wire limit switches
keep it simple
overtravel 10mm for soft limits
!!!
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This is what I think you are asking for, two switches from the same axis connected to one input
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12v out
input pin x axis ++ -- limit
ground
i can take the 12v and the ground on the controller step that down to 5v and use the ground for the returning 5v to ground
the ground pin can be used for both 12v and 5v was confusing me
-or it isnt possible?
I am a novice
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oh, and thank you
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Sorry to disappoint you but 2.2.8 shows the inputs expect a connection to 12V, not to ground like many breakout boards.
The sensor you have chosen will not work with this type input. Perhaps Omron makes a version with the same physical dimensions that has the right electrical features. I take a look.
oh, and you're welcome
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A quick look gave no results from Omron, you'll have to widen the search. Probably you will have to make a new mount to fit what you find.
The correct sensor needs to run on 12V input power and have a PNP transistor output, Also the output needs to turn on when the light is blocked.
Post a part number if you find a likely candidate.
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AHH,
So fudge some 12v limits for now.
Then get the ess smoothie, with 5v I/o and a 5v I/o Bob, hook that to them in the future when fitting to be e 200w servos.
Great idea