Triconex 3351S2 Analog Input Module

Technical Specifications Number of Input Channels: 8 isolated analog input channels Input Signal Range: 4‑20 mA DC analog current signal A/D Conversion Resolution: 16‑bit Measurement Accuracy: Less than 0.1% of full‑scale range Input Burden Resistance: 250 Ω per channel Channel‑to‑logic Isolation Voltage: 2500 V RMS Backplane Interface: Tricon TriBus redundant backplane bus Operating Temperature: -40 °C to +70 °C Storage Temperature: -50 °C to +85 °C Certifications: SIL3, IEC61508, ATEX, UL, TÜV Module Form: Single‑slot plug‑in Tricon rack module Weight: 0.48 kg

Functional Features Triple‑modular redundant analog‑sampling circuit for each channel. Hardware electrical isolation for each analog input channel. Built‑in loop‑supply capability for two‑wire field transmitters. Detect field‑loop open‑circuit fault for each analog channel. Support hot‑swap online module replacement without interrupting system running. Comprehensive self‑diagnosis covering internal circuit, A/D conversion and field‑loop status. Front‑panel LED indicators for module pass, fault and channel‑active status. Range‑scaling and alarm‑threshold configuration supported via TriStation software.

Application Scenarios Analog‑signal acquisition for petrochemical SIS emergency‑shutdown system. Pressure, level and flow transmitter signal input for oil‑gas process‑safety system. Temperature‑transmitter analog‑data collection for chemical‑plant safety interlock loops. Power‑plant boiler and turbine safety‑related process‑variable monitoring. Refinery flare‑system safety‑instrument‑signal acquisition. Fire‑and‑gas‑system analog‑detector signal input.

Performance Parameters Voting Logic: Two‑out‑of‑three voting of three‑branch analog sampling values Conversion Update Rate: Synchronized with Tricon system deterministic scan cycle Open‑circuit Detection: Reliably identify two‑wire transmitter loop open‑circuit fault Temperature Drift: Low full‑scale measurement drift across full operating‑temperature range

Material Composition Main circuit board: Industrial conformal‑coated printed circuit board. Mechanical frame: Reinforced alloy rack‑insertion bracket. Connector assemblies: Gold‑plated backplane golden finger and termination‑panel interface connectors. Internal components: Precision analog‑to‑digital conversion chips, isolation optocouplers, precision reference resistors, loop‑power‑supply circuits. Fasteners: Vibration‑resistant anti‑loosening metal screws.

Structural Characteristics Single‑slot plug‑in design compatible with Tricon standard rack chassis. Front‑panel LED indicator group showing module health and each‑channel status. Field instrument wiring connected through external termination panel. Backplane golden finger interface for TriBus redundant backplane‑bus connection. Integrated electromagnetic‑interference‑suppression shielding structure. Mechanical locking buckle for firm fixing inside rack slot.

Working Principle 4‑20 mA analog signal from field two‑wire transmitter flows through module input‑channel burden resistor and converts to voltage signal. Isolation optocoupler completes electrical isolation between field‑instrument side and internal logic circuit. Three independent redundant branches perform analog‑to‑digital sampling conversion for same channel signal. Internal voting circuit executes two‑out‑of‑three voting for three‑group sampled values. Valid voted digital‑process‑variable data transmits to main processor via TriBus backplane bus. Diagnostic circuit monitors loop‑current magnitude continuously, triggers open‑circuit fault alarm when current falls below lower threshold and uploads fault‑status information to system controller.

Installation Requirements Install analog‑input module in designated I/O slot of Tricon rack chassis. Complete reliable chassis protective‑grounding following official grounding specification. Field transmitter wiring must adopt shielded twisted‑pair cables. Separate analog‑signal cables and high‑power power‑cable routing. Confirm field two‑wire transmitter load requirement matches module loop‑supply capacity. Hot‑swap replacement must strictly comply with site safety‑operation procedure. Control‑cabinet ambient temperature and humidity stay within rated operating scope without condensation. Termination‑panel wiring‑screw torque follows manufacturer recommended value.