1.6.2 I/O Redundancy
There are various options available for single and multiple packs and single and dual networks for I/O redundancy. The
following are options for TMR I/O modules:
•
Single Pack Dual Network I/O Module (SPDN)
•
Two Single Pack, Single Network (2SPSN) I/O Modules
•
Dual Pack, Dual Network (DPDN) I/O Module
•
Triple Pack, Dual Network (TPDN) I/O Module
•
Hot Backup I/O Module
1.6.2.1 Single Pack Dual Network I/O Module (SPDN)
This configuration is typically used for non-critical single sensor I/O. A single sensor connects to a single set of acquisition
electronics which is then connected to two networks.
•
Single data acquisition
•
Redundant network
The I/O pack delivers input data on both networks at the beginning of the frame and receives output data from both
controllers at the end of the frame.
1.6.2.2 Two Single Pack, Single Network (2SPSN) I/O Modules
This configuration is typically used for inputs where there are multiple sensors monitoring the same process points. Two
sensors are connected to two independent I/O modules.
•
Redundant sensors
•
Redundant data acquisition
•
Redundant network
•
Online repair
Each I/O pack delivers input data on a separate network at the beginning of the frame and receives output data from separate
controllers at the end of the frame.
1.6.2.3 Dual Pack, Dual Network (DPDN) I/O Module
This is a special case for inputs only, using a dual pack, dual network module. A fanned input terminal board can be populated
with two packs providing redundant data acquisition for a set of inputs.
•
Redundant data acquisition
•
Redundant network
•
Online repair
Each I/O pack delivers input data on a separate network at the beginning of the frame.
Control System Overview
Public Information
GEH-6721_Vol_I_BP System Guide 41