Emerson PACSystems Versamax - Operation; NIU Data Memories

PACSystems VersaMax Genius Network Interface User Manual Section 3
GFK-1535D Jan 2023
Operation 46
Section 3: Operation
This section explains how the Genius NIU interacts with the modules in its
station, how it stores data, and how it exchanges data on the Genius bus.
• NIU data memories
• Scanning inputs and outputs in the I/O Station
• Data transfer between the Genius NIU and the Genius bus
• Genius bus scan time
• Operation of the Genius NIU in Enhanced Diagnostics Mode
Genius Hand-held Monitor Use
The Network Interface Unit does not have a Hand-held Monitor
connection. A Genius Hand-held Monitor cannot be used to configure,
monitor I/O, force I/O, or unforce I/O of a Genius NIU.
If there is a Hand-held Monitor elsewhere on the bus, it will display the
presence of the NIU on the bus as an “unsupported device”.
3.1 NIU Data Memories
All of the data for the I/O station utilizes the NIU's four I/O data
memories. The NIU has 128 bytes of memory available for each of the
four types of data (discrete inputs and outputs, data types I and Q, and
analog inputs and outputs, data types AI and AQ). During NIU
configuration, data for individual modules are assigned to specific areas
of this memory.
NIU Memory
Type
Typically Used For
Amount
Available in NIU
I
Discrete inputs, and status data from intelligent modules
(each byte contains 8 input points)
128 bytes
Q
Discrete outputs, and fault clearing for intelligent
modules (each byte contains 8 output points)
128 bytes
AI
Analog inputs (requires 2 bytes per channel)
128 bytes
AQ
Analog outputs (requires 2 bytes per channel)
128 bytes
Data always starts at the beginning of each table.
Each table starts at 1 internally. The combination of analog channels and
discrete points must not exceed 128 bytes for inputs and 128 bytes for
outputs.