SKU: AO 3481S2

Triconex AO 3481S2 Analog Output Module

The Triconex AO 3481S2 is an 8-channel TMR Analog Output module designed for SIL 3 safety systems. It provides high-precision 4-20mA control with triple-redundant voting logic and integrated self-calibration for mission-critical industrial loops.

Triple Modular Redundancy (TMR) Output Integrity

The Triconex AO 3481S2 is a high-reliability Analog Output module engineered for the Tricon Triple Modular Redundant (TMR) safety system. This module is essential for controlling critical final elements, such as control valves or variable speed drives, in environments where a single failure must not lead to a system shutdown or unsafe condition. The AO 3481S2 features a unique architecture where three independent sub-circuits vote on the output value. This ensures that the actual current or voltage delivered to the field remains accurate and stable, even if one of the internal legs of the module encounters a hardware fault.

Comprehensive Technical Specifications

Manufacturer: Triconex (Schneider Electric)
Model Number: AO 3481S2
Module Type: TMR Analog Output (8 Channels)
Output Signal Range: 4–20 mA (Standard)
Accuracy: ±0.1% of FSR (Full Scale Range) from 0° to 60° C
Resolution: 12-bit
Safety Integrity Level: SIL 3 Capable
Module Weight: 1.82 kg
Module Dimensions: 3.2 cm x 26.5 cm x 35.8 cm
Diagnostics: Output current loop monitoring and internal “Hotway” testing
Isolation: 1500V DC (Chassis to Channel)

Precision Control and Self-Calibration

Automation engineers prefer the AO 3481S2 because it utilizes an advanced mid-value selection algorithm to reconcile data from the three Main Processors. If a discrepancy occurs between the three internal tables, the module automatically identifies the outlier and relies on the median value to maintain the process loop. Additionally, the module features a built-in self-calibration routine. It periodically compares internal reference voltages against the output digital-to-analog converters (DACs), automatically adjusting gain and bias to compensate for thermal drift or component aging. This proactive maintenance feature significantly reduces the need for manual field calibrations.

Primary Safety Applications

Emergency Shutdown (ESD): Controlling modulating valves to safely depressurize a vessel during a trip.
Turbine Control: Precise regulation of fuel valves and governor speed controls in power generation.
Burner Management Systems (BMS): Managing air-to-fuel ratios for large industrial boilers.
Fire and Gas Systems: Driving localized signaling equipment and suppression release actuators.