AND Logic on 24 Volt Signals
A 24V AND gate is easy to do with diode logic. For each input of the AND gate connect the anode of a diode to that input. Connect all of the cathodes to together, and connect a pullup resistor from the diode cathodes to 24V. If any input is low the output will be pulled down to about 0.7V. If all of the inputs are at 24V the output will be 24V. Diodes that can handle 24V are quite inexpensive.







simulate this circuit &ndash; Schematic created using CircuitLab