In the Digital Input Primer, it mentions "To properly interface one of these proximity switches to the digital inputs, a 3-wire proximity switch is required" (http://www.phidgets.com/docs/Digital_In ... ity_Switch). What about 2-wire proximity switches?
With my two wire proximity switch, the inputs on the 0/16/16 stay high, even with the proximity switch is off, which I think makes sense because
"In this system a residual current flows through the load even when in the open state and a voltage drop occurs to the sensor when it is in the closed state. (http://www.fargocontrols.com/sensors/inductive_op.html)"
Is a bleeder resistor needed, and, if so, how doe you calculate appropriate values for it?
http://www.ia.omron.com/product/caution ... t_use.html (images of the equations are broken, unfortunately)