Which specification defines the number of field inputs or outputs that could be connected to a single module?

• A. Points per module
• B. Slots per module
• C. Channels per module
• D. Terminals per module

Answer: (A)

The number of field inputs or outputs a single module can handle is defined by its points per module. In PLC terminology, a “point” is one individual I/O connection—one discrete input or one discrete output. So a module described as having 16 points provides 16 separate I/O connections, while a 32-point module provides 32. This measure directly reflects the I/O density of the module and how much field wiring it can support.

Other terms don’t describe the module’s I/O capacity in the same way. Slots per module refers to how many modules can be placed in a chassis, not how many I/O points a single module provides. Channels per module can describe different things depending on the module (sometimes analog channels or communication paths), but it isn’t the standard way to specify total discrete I/O count. Terminals per module would indicate the physical screw terminals, not the total number of I/O points available.