An industrial automation system comprising: a sensor for providing a signal indicating a state or condition; first and second processors (16, 18) in communication with one another; and an input module in communication with the sensor and the first and second processors, the input module comprising: first and second detection circuits configured to receive the signal for producing first and second outputs to the first and second processors, respectively, wherein the first detection circuit is configured to: (a) produce the first output having a first state upon the signal exceeding a voltage threshold; and (b) produce the first output having a second state upon the signal failing to exceed the voltage threshold, and wherein the second detection circuit is configured to: (a) produce the second output having a first state upon the signal exceeding a current threshold; and (b) produce the second output having a second state upon the signal failing to exceed the current threshold, wherein the first processor is configured to provide a first test signal to the second detection circuit for testing the second output, and the second processor is configured to provide a second test signal to the first detection circuit for testing the first output. a sensor for providing a signal indicating a state or condition; first and second processors (16, 18) in communication with one another; and an input module in communication with the sensor and the first and second processors, the input module comprising: first and second detection circuits configured to receive the signal for producing first and second outputs to the first and second processors, respectively, wherein the first detection circuit is configured to: (a) produce the first output having a first state upon the signal exceeding a voltage threshold; and (b) produce the first output having a second state upon the signal failing to exceed the voltage threshold, and wherein the second detection circuit is configured to: (a) produce the second output having a first state upon the signal exceeding a current threshold; and (b) produce the second output having a second state upon the signal failing to exceed the current threshold, wherein the first processor is configured to provide a first test signal to the second detection circuit for testing the second output, and the second processor is configured to provide a second test signal to the first detection circuit for testing the first output. first and second detection circuits configured to receive the signal for producing first and second outputs to the first and second processors, respectively, wherein the first detection circuit is configured to: (a) produce the first output having a first state upon the signal exceeding a voltage threshold; and (b) produce the first output having a second state upon the signal failing to exceed the voltage threshold, and (a) produce the first output having a first state upon the signal exceeding a voltage threshold; and (b) produce the first output having a second state upon the signal failing to exceed the voltage threshold, and wherein the second detection circuit is configured to: (a) produce the second output having a first state upon the signal exceeding a current threshold; and (b) produce the second output having a second state upon the signal failing to exceed the current threshold, (a) produce the second output having a first state upon the signal exceeding a current threshold; and (b) produce the second output having a second state upon the signal failing to exceed the current threshold, wherein the first processor is configured to provide a first test signal to the second detection circuit for testing the second output, and the second processor is configured to provide a second test signal to the first detection circuit for testing the first output.