Emerson PACSystems Versamax - Scanning Inputs and Outputs in the I;O Station; Data Transfer between the NIU and the Genius Bus

PACSystems VersaMax Genius Network Interface User Manual Section 3
GFK-1535D Jan 2023
Operation 47
3.2 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.
Figure 36: NIU Memories
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.
3.3 Data Transfer Between the NIU and the
Genius Bus
For each Genius bus scan, an NIU exchanges the following data with the
bus:
• It sends an input message with up to 128 bytes of discrete and/or
analog inputs.
• It receives an output message with up to 128 bytes of discrete and/or
analog outputs.
The exact length of these messages is determined by the network I/O
map configured for the NIU.