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Author Topic: Optical Limit Switches  (Read 2972 times)

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Optical Limit Switches
« on: January 11, 2009, 09:40:12 PM »
Hi All,

I have 3 Optek OPB970T55 optical switches that I would like to use to replace the standard micro switch limit switches.  This is for a homemade router table.

I'm currently running 14 volts through one relay with switches wired in series and using shielded wire.  Before the shielded wire and 14 volt relay I was having a heck of a time with noise.  The switches then go to a C-10 breakout board.

My questions are: Should I continue to use the 14 volt source and can these switches still be wired in series like micro switches.  My understanding is the opticals can handle up to 35 volts.  I am I better off leaving well enough alone?

I have enough free inputs to run all of the switches separately if need be as I have added a second parallel port.

Any and all help with the wiring or suggestions is certainly welcomed.

Re: Optical Limit Switches
« Reply #1 on: January 12, 2009, 11:02:02 AM »

For best noise immunity, you should wire them all separately.  For safety, the limits should be directly controlling a relay that cuts power to the axis drives, and NOT depending on Mach3 to be doing that for you, as Mach3 may have lost its mind, and be the cause of the problem.  That means having a small board with logic that combines all the switched into a single relay control signal.  I'm in the process of building optical limits for my knee mill, and making a PCB to interface the optos to the BOB, and provide the combining logic and relay drivers.

Ray L.
Ray L.