limit switch

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larryl
Posts: 5
Joined: Tue May 03, 2016 12:18 pm
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limit switch

Post by larryl »

on my machine z+x-y- (home) limit switches are norm, open. can i change a default setting to to use them ?
cnckeith
Posts: 7164
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Re: limit switch

Post by cnckeith »

yes. check out the installation manual. it tells you how to "flip" any input from NO (normally open) to NC (normally closed).

but before you do that.. check your switches carefully.. most of them have both NO and NC closed terminals or wires. I run into this all the time on early boss retrofits.. the old control used the NO connections.. so all i do is move the one wire over to the NC connection.
its generally agreed that setting up limits as NC is the best practice.
Need support? READ THIS POST first. http://centroidcncforum.com/viewtopic.php?f=60&t=1043
All Acorn Documentation is located here: viewtopic.php?f=60&t=3397
Answers to common questions: viewforum.php?f=63
and here viewforum.php?f=61
Gear we use but don't sell. https://www.centroidcnc.com/centroid_di ... _gear.html
larryl
Posts: 5
Joined: Tue May 03, 2016 12:18 pm
Allin1DC CNC Controller: No
CNC Control System Serial Number: a900508
DC3IOB: No
CNC11: Yes
CPU10 or CPU7: No

Re: limit switch

Post by larryl »

thank you. i agree on the nc. ill check the switch wiring
cncsnw
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Joined: Wed Mar 24, 2010 5:48 pm

Re: limit switch

Post by cncsnw »

For the benefit of others reading this thread:

The original poster has a GPIO4D system, where the limit switches are strictly software logic. If needed, he can wire normally-open switches, and invert the sense in the PLC software. This would also work fine with an Oak, GPIO4D/OpticDirect, or RTK4 control system.

It would not work with an All-in-one DC system, because the All-in-one DC also uses the limit switch inputs as hardware inhibits for the respective axes. Therefore the All-in-one DC requires normally-closed limit switches. If it is impossible to provide normally-closed switches on an All-in-one DC, then you have to leave INP1-INP6 vacant; defeat them with the DIP switches; and wire your normally-open limits to higher-numbered PLC inputs.
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