Limit Switch Isolator Setup

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EccentricWorkshop
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Limit Switch Isolator Setup

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Post by EccentricWorkshop » 2 weeks ago

I got another question today about making connections to and using the Limit Switch Isolator.

When looking at the PCB from the top with the mounting holes up, the left side if the board is for connections to physical limit switches. The top terminal in each terminal block is for the switch ground connection. The lower terminal is for the switch connection and goes into the optoisolator.

The right side terminal blocks are for connections to the Arduino limit switch pins. The top three terminals are used, one terminal is unused, and the bottom two are for ground and 5v DC from the Arduino.

As it is good practice when using opto-isolators, a separate power supply is required to drive the optoisolators themselves which is done through the top center terminal block. This provides the greatest noise isolation.

For most cases, the GRBLDuino Limit Switch Isolator will have two power sources entering the board. Both are required for the board to work properly and provide the greatest noise isolation. Should you want to only use one power supply (the Arduino) and reduce effectiveness of the opto-isolators, you can solder the jumper pads at the top right (labeled JP0/JP1).

Additional details about limit switches and isolation are explained in the GRBL wiki.
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GRBLDuino Limit Switch Isolator Datasheet.pdf
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GRBLDuino Limit Switch Isolator Datasheet.pdf
(385.73 KiB) Downloaded 21 times
LSI_01.jpg
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LSI_01.jpg
LSI_01.jpg (843.39 KiB) Viewed 11 times
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Andy
Eccentric Workshop
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