Thread: Giant 20' x 3' x 2' router build
It was a m10 flat head bolt. The stainless bolt works fine on the short cable
Mechaincal switches are OK for Limits I agree but what does he do then about Home switches.? . . Shouldn't have to put up with lesser accurecy by using mechanical switches.
I'm sure the problem lies with the fact these Cheap chinese switches obviosly don't like the longer wire run and any capacitance thats coming with it.! . . . . . That or he's got some other issue he isn't aware of yet.?
Last edited by EddyCurrent; 31-10-2014 at 01:31 PM.Spelling mistakes are not intentional, I only seem to see them some time after I've posted
Last edited by JAZZCNC; 31-10-2014 at 02:06 PM.
My conclusion is that it's capacitance of the cable so using mechanical switches is not masking it but using a product that will work in that situation.
I never said specifically that proximity switches were the wrong product for the job, but maybe 'those' ones are.
I know full well what sensors of all kinds are made to do having been in industry electricals for over 40 years.
I think the home switches will be okay because of the slow approach speed.
All other aspects I think are what is to be expected with DIY.
Last edited by EddyCurrent; 31-10-2014 at 02:46 PM.Spelling mistakes are not intentional, I only seem to see them some time after I've posted
The home switches are not Ok even at homing speeds this has been tried.! Also how can they be trusted if we haven't conclusively found the cause.?
Your method while yes maybe getting the machine working isn't the correct one IMO. It's still a mask for the real cause and who's to say this cause isn't going affect other aspects of the machine later down the line.? . . . .What if it is a wiring or grounding issue that isn't found now but surfaces at a later date when newness wears off or other attachments get added like probes etc which could suffer from same issue.?
Best resolved now and after all obvious causes have been eliminated then the next logical choice is to replace suspect components for same type or like in this case with same type but being of better quality. Changing to a compleltely diffeant switch type will in this case potentially mask some other cause or fault.!
Thanks for all the input guys I went to rs but they didn't have anything suitable in stock and it would be 3-4 weeks the chap was looking at some by omron ? So unfortunately walked away with nothing. Tony has just found two to try from a place near him in Leicester and he is going to bring some micro switches down tomorrow as we'll just for a test per poses, hopefuly a second brain will help find out what's going on so fingers crossed. Many thanks for all the help it's much appreciated having people to bounce ideas around with.
The solution to the capacitance issue, if that's what it is, is to buffer the switches locally. It's not clear to me where the switches are located but a simple transistor or IC buffer would fix it at very low cost and could handle multiple switches if they are close together.
Last edited by irving2008; 31-10-2014 at 09:58 PM.
If charlie's keen he could put differential signalling ICs (e.g. MAX488) on both ends and may alleviate problems later on. They're low cost and easy to implement since the circuit's in the datasheet...probably excessive though so personally I'd try a transistor first as it'd take 2 mins to test.
Last edited by Jonathan; 31-10-2014 at 10:23 PM.
The switches are all on the gantry on the moving side of each axis, just let me know what I need to do to try your idea and I will give it a shot if I can get the stuff as I don't really understand what you are saying at the moment.
Last edited by charlieuk; 01-11-2014 at 12:33 AM.
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