Signals that are read or measured are called input signals. Those signals that are generated are called output, or standard output. Some specialized devices also support a Wired-OR output. Refer to the device documentation for more information about the types of input and output the device supports.

This section covers software-timed digital input/output operations—or unstrobed operations. These signals are controlled by software timing.

Measuring and generating digital values are used in a number of applications, including controlling relays and monitoring alarm states. Generally, measuring and generating digital values is used in laboratory testing, production testing, and industrial process monitoring and control.