How many inputs are needed for limit switches?

[RPCElectronics]

Now that I have my machine going, I am looking at adding limit switches to my X2. However, I used my available inputs (only four) for a homebrew jog controller and still only had enough for X and Y. What are most of you doing for enough inputs? For my limit switches, it looks like I need a minimum of six inputs total. I'm thinking about just added on a second parallel port card to increase my number of inputs.

[hoss2006]

You only need one input for all home and limit switches (Normally Closed) if you wire them in series, it's a common way to do it and my preferred method, works perfectly well.
Hoss

[RPCElectronics]

You only need one input for all home and limit switches (Normally Closed) if you wire them in series, it's a common way to do it and my preferred method, works perfectly well.
Hoss

Ah! I didn't even think of doing it that way. You have to forgive me, I come from an electronics background where I am always thinking of tying every to an individual input (I guess it comes from my microprocessor background).

So, I guess I can just tie them all into my E-Stop circuit?

Thanks!

[RTTIM]

Ah! I didn't even think of doing it that way. You have to forgive me, I come from an electronics background where I am always thinking of tying every to an individual input (I guess it comes from my microprocessor background).

So, I guess I can just tie them all into my E-Stop circuit?

Thanks!

Not the E-stop - you need one input for limit/home switches.

Pretty good info in this linked document...

http://www.marchantdice.com/forumima...t-switches.pdf

Tim

[109jb]

Not sure about different controller software, but in EMC, you don't have to use normally closed switches in series for a single input. Normally open switches can be wired in parallel to get the same result. You just have to change the proper setting in the stepconfig wizard depending on what style switch you use. Many mechanical switches have both NO and NC contacts. I have ordered NO switches for my round column mill. I am using going to use inductive proximity switches. It will be a while before I get them installed though since they are coming from the other side of the globe and I just ordered them on Monday. My plan is to install them as X-, Y- and Z+ limit/home switches and use the soft limits for the other direction. This should allow automatic homing which is what I am really after. I'll report how repeatable the switches are once I get them installed.