Which statement about discrete I/O modules being bit oriented is true?

• A. They process analog signals
• B. They represent individual binary points
• C. They store data in RAM
• D. They perform high-speed networking

Answer: (B)

Discrete I/O modules are designed to handle digital signals, where each channel corresponds to a single binary state—on or off. This is what being bit oriented means: every input or output point is one bit in the PLC’s I/O image, so sensors and actuators are represented as individual binary points. That’s why these modules are ideal for straightforward on/off status like a pushbutton, a limit switch, or a relay coil.

They don’t process analog values, which would require measuring continuous ranges and converting them to a multi-bit value. They don’t store data in RAM as part of the module’s function; memory storage is the PLC’s job for program data and variable values, not the discrete I/O channels themselves. And they aren’t meant for high-speed networking; while some I/O modules may include network capabilities, the core concept of being bit oriented is about handling individual digital points, not networking.

So the statement that they represent individual binary points is the best fit.