Network Router User Manual

GFK-1535A Chapter 3 Operation 3-3

Scanning Inputs and Outputs in the I/O Station

The NIU performs a regular I/O scan of all inputs and outputs.

During each I/O scan, the NIU reads inputs from all discrete and analog input

modules and places the data into its I and AI memories.

The NIU also sends outputs from its Q and AQ memories to all discrete and analog

output modules.

NIU Memories

Discrete Input

Modules

Discrete Output

Modules

Analog Input

Modules

Analog Output

Modules

Data Handling for Modules with More than One Data Type

Some modules have multiple types of I/O data. The NIU reads all input data from

these modules and sends all their output data during every I/O scan.

NIU Memories

Module