| HOW TO CONNECT XYLOTEX DRIVE TO LIMIT SWITCHES | HOME |
| On the right is a schematic for a simple limit switch. The parallel port pin is connected to the computer's +5vdc power supply through a 4.7k to 10kΩ resistor. The resistor protects the parallel port from the excess current that it would receive were the pin directly hot wired to the power supply. The 5v pulls the pin high. Also wired to the same pin on the parallel port are the Normally Closed limit switches linked in series. One wire is connected to the pin and the other wire from the switches is grounded to the computer's power supply low voltage ground. When the switches are all closed, the parallel port pin sees ground. It will be pulled low since the current from the power supply will take the path of least resistance and seek ground through the switches rather than through the parallel port. When any one of the switches is open the current will travel to the parallel port pin, and the pin will be pulled high. The software is told to stop the machine when the signal is high. |
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