Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: kolias on March 20, 2022, 02:00:28 PM
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I bought these Proximity Sensor package few years back when I was finishing my last cnc (Mach3, G540, VFD, Water Cooled Spindle) but decided to use Micro Limits instead.
Now for my new cnc I decided to use for the first time ESS/C11G BOB instead of a parallel printer cable, and I wonder if I can mix these Proximity Sensors in Y/A/X axes with Micro Limit Switches in the Z axis. I will still use Mach3 for now.
I never used Prox. Sensors before and to my opinion it will be very difficult to locate these sensors on the Z axis due to limited space so I was thinking to install the Micro ones (Z+, Z-),
However my question is would mixing 2 different kind of Limits create complications?
Thanks
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Hi,
why use a C11 breakout board?. You've gone to the trouble and expense of buying an ESS that has three parallel port equivalents....only to use one of them?
A C25 is a better unit. It plugs directly on top of the ESS, no ribbon cables required and it has two ports, ie 34 inputs and outputs and its less than half the price.
It does not have relays nor does it have a PWM circuit, which you would have to add, but you'd have two ports worth of IO, not one.
With the number of inputs you'd have to spare you could have one limit/home switch per input, and then you could mix them at will.
Craig
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All electrical items have been bought Joe as a package and you can’t get a ESS with only one parallel port. Perhaps in the future I may have a need for the extra ports.
I went for the C11 because I need the relays and felt will be easier to connect/control my Sherline motor with nothing more to add.
So you are saying there is no problem mixing the limit switches, many thanks.
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Hi,
the problem is that with the C11 BoB you only have five inputs, so you have to mix the microswitches and the prox sensors.
It can be done but you are making it hard for yourself.
With microswitches it was common to link them altogether in series, if any one of them went open Mach would know about it.
You can't link prox switches in series, you can link the in parallel, but its a hassle.
Simple idea, get another C10 BoB and use a second port of the ESS, with pins 2-9 as inputs, and now you have enough inputs to have
one switch one input, which is by far and away the best and simplest of solutions. A C10 is $23.00
Trying to combine switches is the 'old parallel port mentality'....whereas you have stepped way past that into a genuine IO paradise....take advantage of it!
Craig
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Good idea Craig, thanks, but I have to think about it.$23.00 that’s USD + shipping + duties + taxes we come to about $50.00CAD. Plus I will need an extra ribbon to connect it to ESS and perhaps a 5VDC PS if I don’t have one. However I like the idea of having the extra inputs.
Kind of too early to think about it, still building the cnc frame now and I ordered the other electronics to get an idea of the control panel size.
I’m aware of the prox switches connected in parallel, true it’s a hassle, and that’s why I didn’t use them before.
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Hi,
$23USD = $34.30NZD
15% GST(NZ Tax)=$5.15NZD
Shipping to NZ=$32.00NZD
TOTAL =$71.45NZD or $62.20CAD
Given that New Zealand is 9,000-10,000 k's away...that sounds about right. Quite frankly I paid over $1800NZD just for ballscrews, a pesky $71.45NZD wouldn't slow me down.
Craig
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I didn’t say I wouldn’t do it Craig, just right now I will not bother to order the C11 but when the time is right most likely I will. $1800NZD just for ballscrews? Most likely quite high end!
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Hi,
$1800NZD just for ballscrews? Most likely quite high end!
Yes they are, and they are second hand at that!
Three by 750mm long 32mm dia ground C5 double nut (BNFN) by THK with six FK25 support bearings. Would probably be worth $3000NZD
each if I were to buy new.
Craig
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Wow.. and even second hand? I guess the ground C5 and support bearings is the most cost but out of curiosity what the heck you are doing Craig and you need such a precision? Perhaps a machine shop?
In comparison for a set of linear rails and ball screws for 4 axes (approx. equal length as yours) I pay less than 50% and what I get is more than enough for my hobby needs. Have a look at this link, it shows what I built about 10 years ago and all are similar and dead accurate.
New Build (machsupport.com)
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For some reason the link was not clickable, hope I'm not doing something wrong guys
https://www.machsupport.com/forum/index.php?topic=20984.0
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Hi,
I guess the ground C5 and support bearings is the most cost but out of curiosity what the heck you are doing Craig and you need such a precision? Perhaps a machine shop?
No, nothing like that. I made a mini-mill (travels 180mm x 180mm x 180mm) with 20mm C5 ballscrews, 15mm linear rails on cast iron beds eight years ago. I made it mainly for making
circuit boards but wanted to be capable of milling steels as well. It was just barely capable of milling steel, despite being all cast iron and steel construction the cutting forces caused enough
flexure to interfere with cutting accuracy.
I could perhaps have modified it to overcome most if not all of its shortcomings but really wanted to build anew incorporating what I had learned. It was always my intention to get cast iron
axis beds cast for me, and that rather set the tone throughout the design and build. My previous mini-mill also cast iron axis beds, but I milled them out of large cast iron elevator weights
I bought from the scrap yard. They worked out pretty well but the cast iron of a weight is pretty poor, it had inclusions and a really hard and abrasive outer rime. I swore the next time I would do
better, and I did but the cost....oh crikey... the cost!! The castings (3 at 115kg each) cost $3500NZD, and the machining and stress relieving cost another $6000NZD. I sort of have to consider
that I did not control the costs as I should have, and that could be considered a failure, however I've got a superb result and that's what I paid for.
Finding the ballscrews I mentioned was another important part of the project. Ground C5 ballscrews are really expensive, that I was able to find three matching ballscrews in near new condition
for 1/5-1/3 the cost of new allowed me to proceed. Because the ballscrews are all the same length the travels are cubic, that is to say 350mm x 350mm x 350mm. From the same Korean company from
whom I bought the ballscrews I also bought three matching pairs of 20mm HSR (heavy duty) linear rails by THK, they were new old stock, and was able to buy at a much better price than new.
I decided that I wanted servos for this build, so bought a 400W Delta B2 series (160,000 count per rev) AC servo. It far exceeded my expectation of performance, so I then bought three
750W B2 series servos, one with a brake for the Z axis. They have proven to be superb.....and they EAT any stepper ever made!
This is still a hobby mill, but I use it daily for work. Mainly for making circuit boards, for which its is overkill, but also for many small parts in brass, aluminum and plastics for automotive instruments,
but I now also have genuine steel and stainless capacity, which was always my intent starting eight-nine years ago.
Craig
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Beautiful mill you got there Craig and I can “feel” its power. Looks like you spent a lot of time and money but at least you got something to enjoy, congrats!
I did something similar but in a “miniature” scale in comparison to yours. About 3 years ago I decided to stop making cnc’s and build a lathe/mill combo (with 2 Taig spindles) to learn machining as a hobby. I didn’t succeed to learn machining (lol) but I built a very good jig which I used to practice a bit and then took it apart and used some parts to build my new cnc I’m doing now. I learned a few things about machining but I understood my interest is more at making “stuff” than using them!