GE DS3820RTDD

Key Parameters

• Channels: 4 redundant input channels (each with 2 independent RTD sensing elements – total 8 sensing elements)

• Sensor Type: Dual-element Pt100 (2-wire, 3-wire, or 4-wire per element – software-configurable per channel)

• Resolution: 24-bit ADC

• Accuracy: ±0.05°C (Pt100, 25°C); ±0.2°C over –40°C to +70°C

• Excitation Current: Software-selectable 0.1 mA, 0.5 mA, 1 mA (per channel)

• Lead Resistance Compensation: Automatic for 3-wire and 4-wire configurations

• Measurement Range: –200°C to +850°C

• Redundancy Mode: Active/Standby with automatic fail-over (switchover time < 10 ms) when one element fails or deviates beyond threshold

• Sensor Diagnostics: Element mismatch detection, open-circuit detection, short-circuit detection, signal-loss detection

• EMC/Noise Rejection: Enhanced CMRR > 120 dB, built-in 50/60 Hz digital filtering

• Isolation: 1500 V RMS (field-to-backplane); 500 V RMS between channels (per-channel isolation)

• Sampling Rate: Up to 50 Hz per channel (with 50/60 Hz noise rejection)

• Terminal Type: Screw-type – per suffix “D”

• Power: 24 V DC backplane power, ≤5.5 W (plus external field supply)

• Operating Temperature: –40°C to +70°C

Advantages

• Dual-element sensor support – each channel supports a single dual-element RTD sensor; built-in redundancy without requiring two separate sensors and wiring paths.

• Automatic element fail-over (< 10 ms) – seamlessly switches to the secondary element if the primary element fails or shows excessive deviation.

• Element mismatch detection – continuously compares both elements and alerts if readings differ beyond a configurable threshold (early warning of sensor degradation).

• Enhanced EMI protection – CMRR > 120 dB; ideal for installations near VFDs and high-power equipment.

• Screw-type terminals – familiar and secure wiring for traditional panel installations.

• 24-bit resolution – provides superior measurement fidelity.

• Per-channel isolation – 500 V between channels; prevents ground loops and cross-channel interference.

• Automatic lead compensation – for 3-wire/4-wire RTDs, cancels lead resistance errors.

• Built-in linearization – provides direct temperature readout in °C or °F.

• Hot-swappable – replace without rack power-down.

• Wide measurement range – –200°C to +850°C covers most industrial applications.

Applications

• Nuclear power plants – redundant temperature monitoring in safety-critical reactor cooling systems using dual-element sensors

• Oil & gas pipelines – critical pipeline temperature monitoring with built-in sensor redundancy

• Chemical processing – reactor temperature control in exothermic processes requiring redundancy

• Pharmaceutical manufacturing – critical fermenter and storage temperature control with regulatory compliance

• Aerospace – engine and component thermal monitoring with dual-element RTD sensors

• Power generation – turbine bearing and generator temperature monitoring with high-availability requirements

• Data centers – cooling system temperature monitoring with redundant sensor elements

• Food processing – critical oven and sterilization temperature control

Competitor Comparison

The DS3820RTDD is the screw-terminal variant of the dual-element RTD redundant input module – offering four channels, each supporting a single dual-element Pt100 sensor with built-in redundancy. Compared to the spring-clamp DS3820RTDB, it offers traditional screw-terminal wiring for panels where vibration is less of a concern, while maintaining the same enhanced EMI protection, element mismatch detection, and automatic fail-over capability. Against standard single-element Pt100 modules, it adds fail-over capability, element mismatch detection, and enhanced diagnostics – essential for safety-critical applications. For redundant temperature monitoring with screw-terminal wiring, the DS3820RTDD delivers the most reliable and cost-effective solution.

Selection Tips

• Choose DS3820RTDD when you need redundant temperature monitoring using dual-element RTD sensors with screw-terminal wiring – ideal for safety-critical systems with traditional panel installations.

• Perfect for nuclear, oil & gas, chemical, pharmaceutical, aerospace, and power generation applications.

• Use dual-element Pt100 sensors (4-wire recommended) – one sensor per channel provides two independent sensing elements.

• Verify the wire configuration (2-wire, 3-wire, or 4-wire) – software-configurable per channel.

• Configure mismatch detection threshold – alerts if primary and secondary elements differ beyond the set point.

• Not suitable for single-element RTDs or thermocouples – use dedicated modules.

• Ensure your PLC/DCS can handle redundant data processing and fail-over logic from the DS3820RTDD.

Precautions

• Dual-element sensor wiring: For 4-wire dual-element sensors, ensure correct pairing – the DS3820RTDD expects two independent element connections per channel.

• Lead resistance: For 2-wire sensors, lead resistance directly adds error – use 3-wire or 4-wire for accurate measurements. The DS3820RTDD compensates for 3-wire/4-wire automatically.

• Excitation current: Higher currents (1 mA) produce self-heating errors in small RTD elements – use 0.1 mA or 0.5 mA for sensitive sensors.

• Wiring: Use shielded twisted-pair cables; ground shield at module end only. Enhanced EMI protection requires proper grounding to achieve >120 dB CMRR.

• Mismatch threshold: Configure a realistic mismatch threshold (e.g., 2–5°C) – too tight may cause nuisance alarms; too loose may delay failure detection.

• Fail-over testing: Test fail-over behavior during commissioning – force a primary element fault and verify the DS3820RTDD switches to secondary within < 10 ms.

• Power sequencing: Apply backplane power before field power.

• Calibration: Perform periodic calibration using precision resistors – calibrate both elements of each dual-element sensor.

• Spare: Keep one spare DS3820RTDD for critical redundant loops – the screw-terminal variant may have longer lead times.