Does anyone know of a circuit or device that would let me have a simple series e-stop string (using one N.C. contact per e-stop only) and still get individual status of each switch?
You can try a loop-back test if you can connect pins 2 and 3 on the laptop's 9 pin connector. You have to use a terminal emulator like Hyperterminal that comes with Windows. Start a connection thru that port then anything you type should be echoed to Hyperterminal as long as the pins are connected.
UL 508 gives guidelines for making a product UL certified. It follows the NFPA pretty much but has specifics on enclosure type, component spacing etc. In general, the components used in a UL control panel must themselves be UL listed. UL is primarily used is if you are planning on selling a...
I would think this would fall under the "industrial machine" catagory that is addressed by NFPA 79. The NFPA also puts out the NEC which is geared more to building wiring than to individual machines or systems.
