14
Controller Architecture
Trident Planning and Installation Guide
OVD detects and alarms two different types of faults:
• Points— all stuck-on and stuck-off points are detected in less than 500
milliseconds, typically.
• Switches—all stuck-on or stuck-off switches or their associated drive
circuitry are detected.
During OVD execution, the commanded state of each point is momentarily
reversed on one of the output drivers, one after another. Loop-back on the module
allows each ASIC to read the output value for the point to determine whether a
latent fault exists within the output circuit. The output signal transition is
guaranteed to be less than 2 milliseconds (500 microseconds is typical) and is
transparent to most field devices. For devices that cannot tolerate a signal transition
of any length, OVD can be disabled.
OVD is designed specifically to check outputs which typically remain in one state
for long periods of time. The OVD strategy for a DO Module ensures full fault
coverage of the output circuitry even if the commanded state of the points never
changes.
Pulse Input Module
On a PI Module, each channel measures the input frequency independently.
Special algorithms, optimized for accurately measuring the speed of rotating
machinery, are used to compensate for irregularly spaced teeth on timing gear or
for periodic acceleration/de-acceleration. The results are placed into a table of
values. Each input table is passed to its associated MP using the corresponding I
⁄
O
bus. The input table in each MP is transferred to its neighbors across the TriBus.
The middle value is selected by each MP and the input table in each MP is
corrected accordingly. In TMR mode, the mid-value is used by the application; in
duplex mode, the average is used. Special self-test circuitry is provided to diagnose
the health state of all input points, even when an active signal is not present. Each
PI Module is guaranteed to remain in calibration for the life of the controller;
periodic manual calibration is not required.
Solid-State Relay Output Module
On a Solid-State Relay Output (SRO) Module, output signals are received from the
MPs on each of three channels. The three sets of signals are voted and the voted
data is used to drive the 32 individual relays. Each output has a loop-back circuit
which verifies the operation of each relay switch independently of the presence of
a load. Ongoing diagnostics test the operational status of the SRO Module.
Содержание Trident
Страница 1: ...Trident Version 1 2 Triconex An Invensys Company Planning and Installation Guide ...
Страница 10: ...x Contents Trident Planning and Installation Guide ...
Страница 16: ...xvi Training Trident Planning and Installation Guide ...
Страница 53: ...Main Processor Module 37 Chapter 3 System Description Model 2101 Main Processor Baseplate ...
Страница 63: ...Communication Module 47 Chapter 3 System Description Model 2201 Communication Module Baseplate ...
Страница 106: ...90 Input Output Modules Trident Planning and Installation Guide Model 2401 Digital Output Baseplate ...
Страница 128: ...112 Input Output Modules Trident Planning and Installation Guide Model 2451 Solid State Relay Output Baseplate ...
Страница 140: ...124 Covers Trident Planning and Installation Guide ...
Страница 145: ...Guidelines 129 Chapter 4 Installation and Maintenance Depth Dimensions for Baseplate and Module ...
Страница 216: ...200 Replacing Modules Trident Planning and Installation Guide ...
Страница 238: ...222 Diagread Cables and Debug Connectors Trident Planning and Installation Guide ...
Страница 240: ...224 Trident Planning and Installation Guide ...
Страница 248: ...232 Trident Planning and Installation Guide ...
Страница 264: ...248 Glossary Trident Planning and Installation Guide ...
Страница 274: ...258 Index Trident Planning and Installation Guide ...