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Author Topic: I feel somewhat stupid asking but.......  (Read 2171 times)

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Offline nobby

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I feel somewhat stupid asking but.......
« on: February 23, 2014, 03:00:44 PM »
I have connected the limit switches
top of the z
left for x and y
they are closed.
my question is - how do I actually connect them to the break out board.
on the ports and pins screen it says
X++
X--
X HOME
am I supposed to come out of X=+ and back in after the switch to X--
it says only pins 10, 11, 12, 13 and 15 are inputs.
that mean I  the other pins are outputs?
/\ I have looked everywhere this evening on how to, I fear its something simple, but alas I simply don't know what to do.
??????????????????
do I take 5 volts to the switch and then into the pin? does it simply want to see 5v?-
must ask as I don't know and don't want to fry it



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also, as the axis travels and clicks the switch, how farther is it supposed to travel IF at all?
is that what  the slow zone is all about - do you need it?
if its set to one  - is that 1 inch of travel allowable after the switch is triggered, as my z has 5mm the y has 5mm and the x has nothing bar the 10mm bumper

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also whilst setting up the table display mode, and entering 500 for a 500mm travel, the scale looks way out - 30.00 seems correct what am I doing wrong?

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Offline Hood

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Re: I feel somewhat stupid asking but.......
« Reply #1 on: February 24, 2014, 03:21:18 AM »
It willl depend on your breaout board as to whether you supply 5v to an input or connect the input to Gnd. Regarding wiring the limits, if you have Normally closed swithcehes then you can connect them all in series and just use one input or you could connect each axis switches in series and use 3 inputs. You would just have one end of the series of switches connected to the input and the other to either 5v or Gnd, depending on your breakout board.


The X++ and X-- designation in Mach is not referring to electrical polarity but rather the coordiinate system, ie X++ is the switch at the X positive end of travel and X-- is the negative end.

When you use the limits as home switches then when homing the axis will move onto the switch, as soon as Mach sees the switch open it will reverse the axis direction and when the switch again closes Mach will set the the machine coordinates, ie you have homed Mach.

Slow Zone is for Soft Limits and is a zone to tell Mach to start slowing down ready to stop before the axis hits the limit.


Hood

Hood

Offline Fastest1

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Re: I feel somewhat stupid asking but.......
« Reply #2 on: February 24, 2014, 08:56:26 AM »
nobby, Though some breakout boards will require an external voltage for some switches, most that I have seen (hobby level breakout boards) do not. It is a simple switch between whatever pin you assign (must be an input pin) and the ground pin, again usually there is a common ground pin for all switches. Changing the "active low" status will accommodate either style of switch though NC is best.

You must account for momentum of the machine in motion when coming up to a limit switch. It might not seem like much on a machine traveling 60 inch per minute to keep traveling .005 after the switch triggering but if that machine was running 600ipm, the .05 wouldnt be acceptable. Yes that is what the slow zone is about. Set it to .5" or so and a low percentage of its rapid, say 25%. This should keep you safe.

Have you calibrated your axis'? Are they dead on? In General Logic Configuration, do you have DRO's set up to setup units?
« Last Edit: February 24, 2014, 09:04:26 AM by Fastest1 »
I want to die in my sleep like my grandfather, not like the passengers in the car! :-)

Offline nobby

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Re: I feel somewhat stupid asking but.......
« Reply #3 on: February 24, 2014, 02:51:26 PM »
it seems correct?
measuring the distances with a steel rule.
hjavn't cut anything to put a micrometer on yet..
can't find the menu for the dro set up.

Offline nobby

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Re: I feel somewhat stupid asking but.......
« Reply #4 on: February 24, 2014, 02:57:31 PM »
i get it now, if the soft limit is 1 = 1cm 10mm
then the machine will not run as its in the sft limit!!!!!!!
thought it would run from zero.
foooool

so I have to set the offset for atleast 1 everytime?

Offline Fastest1

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Re: I feel somewhat stupid asking but.......
« Reply #5 on: February 24, 2014, 06:09:25 PM »
No. Those are your machine coordinates. There will also be work coordinates set up within the machines boundaries/limits
I want to die in my sleep like my grandfather, not like the passengers in the car! :-)