Description
TRICONEX 3481 Redundant modules
Product Overview:
The TRICONEX 3481 is a triple modular redundant (TMR) analog output module designed for the Tricon safety instrumented system. This specialized module functions as a critical actuation interface, converting voted digital commands from the TMR controller into precise, fault-tolerant analog current signals (typically 4-20 mA) to control final elements in the field. It is engineered for applications where modulating control is part of the safety function, such as positioning control valves, regulating variable speed drives, or providing analog setpoints to other controllers within a safety-critical loop.
Key Features and Advantages:
Fault-Tolerant Analog Output Generation:
The TRICONEX 3481 implements a true TMR architecture for analog output. Three independent digital-to-analog converter (DAC) channels generate three separate 4-20 mA output signals based on commands from the three main processors. These three analog signals are fed into a hardware voting circuit (often a sophisticated averaging or mid-select circuit) that produces a single, highly reliable output to the field. This design ensures that a single channel failure does not cause an erroneous or dangerous output, maintaining the integrity of the safety control action.
High Precision and Loop Diagnostics:
The module provides high-resolution output with excellent accuracy for precise control of field devices. It incorporates comprehensive diagnostics that monitor the health of the output channels and the field loop. Key diagnostics include output current validation (comparing commanded vs. actual current), open circuit detection (broken wire in the field loop), and module hardware fault detection. These diagnostics provide real-time feedback to the safety controller, ensuring the commanded safety action is being correctly executed.
Load Driving Capability and Isolation:
Designed to drive real-world loads, the TRICONEX
3481 can typically drive loads up to a specified resistance (e.g., 750-1000 Ohms). It provides galvanic isolation between the internal TMR electronics and the field output circuit. This isolation protects the sensitive safety system from ground loops, transients, and noise that may be present on the field cabling, which is crucial for reliable long-term operation.
3481 can typically drive loads up to a specified resistance (e.g., 750-1000 Ohms). It provides galvanic isolation between the internal TMR electronics and the field output circuit. This isolation protects the sensitive safety system from ground loops, transients, and noise that may be present on the field cabling, which is crucial for reliable long-term operation.Safety-Oriented Configuration Modes:
The module can be configured with defined behaviors for fault conditions or loss of communication. A critical feature is the ability to set a predefined Fail State Value. If a fault is detected or communication with the main processors is lost, the module can drive its output to a user-configured safe level (e.g., 4 mA to close a valve, or 20 mA to open it), ensuring the process moves to a predetermined safe state upon a system failure.
Technical Specifications:
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Feature
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Specification
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|---|---|
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Product Model
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TRICONEX 3481
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Module Type
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TMR Analog Output Module
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Output Signal
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4-20 mA (isolated)
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Number of Channels
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4 channels (triplicated)
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Output Resolution
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High-resolution (e.g., 12-bit or higher)
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Load Driving Capability
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[Example: Up to 750 Ohms – Note: Exact spec must be verified]
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Key Diagnostics
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Output current validation, open circuit, short circuit, module fault
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Configurable Fail State
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Yes (user-defined 4-20 mA value on fault)
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Application Areas:
The TRICONEX 3481 is deployed in safety instrumented functions that require modulating control rather than simple on/off action. Common applications include controlling vent or bypass valves in pressure relief systems, positioning steam turbine governor valves for speed control, modulating fuel valves in complex burner management systems, and providing analog setpoints to auxiliary controllers in safety-critical chemical reactor processes.
Related Products:
TRICONEX 3805E:
A TMR Digital Output Module. While the TRICONEX 3481 provides analog modulating control, the 3805E provides discrete on/off control for devices like solenoid valves. They represent the two primary types of final actuation in a safety system.
TRICONEX 3700A:
A TMR Analog Input Module. This module provides the complementary function, bringing critical analog process signals (e.g., pressure, temperature) into the safety system. The logic solver uses inputs from the 3700A to calculate the required output for the TRICONEX 3481.
TRICONEX 4351B:
The Main Processor Module. The TRICONEX 3481 receives its independent output commands from the three channels of the TRICONEX 4351B. The main processors execute the safety application logic and send the commands, which are then voted on and converted to an analog signal within the 3481 module itself.
| TRICONEX | 4351B | Communication Module |
| TRICONEX | 3721 | Analog Input Module |
| TRICONEX | 3625 | Digital Output Module |
| TRICONEX | 3625A | Digital Output Module |
| TRICONEX | 3604E | Optically isolated, non-common. Voltage: 24VDC. Number of outputs: 16. |
| TRICONEX | 3504E | High-density—common, DC-coupled. Voltage: 24/48VDC. Number of input points: 64 |
| TRICONEX | 3503E | Digital input module. 8 points per group, shared, with self-test function. Voltage: 24VAC/VDC. Number of input points: 32 |
| TRICONEX | 3700A | Analog Input Module |
| TRICONEX | 3511 | Frequency Module |
| TRICONEX | 3481 | Trident Analog Output Module
|
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