GE DS3820SMTD

Key Parameters

• Channels: 4 analog inputs with simultaneous sampling

• Sensor Type: Pt100 (2-wire, 3-wire, or 4-wire – 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

• Sampling Mode: Simultaneous (all channels sampled at the same instant)

• Sampling Rate: Up to 200 Hz per channel (high-speed mode; filtering disabled)

• Phase Mismatch: < 0.05° at 50/60 Hz (between channels)

• EMC/Noise Rejection: CMRR > 100 dB, built-in 50/60 Hz digital filtering (reduces speed when enabled)

• Diagnostics: Open-circuit detection, short-circuit detection, over-range/under-range, signal-loss detection, per-channel LED status

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

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

• Power: 24 V DC backplane power, ≤4.5 W (plus external field supply)

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

Advantages

• Simultaneous sampling – captures all 4 channels at precisely the same moment; eliminates phase errors between signals – critical for thermal profiling and dynamic analysis.

• Fast 200 Hz sampling – captures rapid temperature changes; ideal for dynamic processes and transient thermal analysis.

• Minimal phase mismatch (< 0.05°) – ensures accurate time-correlated measurements for multi-point thermal analysis.

• 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.

• Software-configurable per channel – wire configuration and excitation current independently settable.

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

• Enhanced diagnostics – includes signal-loss detection for proactive maintenance.

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

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

Applications

• Thermal profiling – mapping temperature gradients across ovens, furnaces, and kilns

• Engine testing – simultaneous exhaust and component temperature monitoring in automotive and aerospace

• Turbine monitoring – high-speed temperature profiling in power generation

• Induction heating – fast-response temperature monitoring for heat treatment

• Semiconductor manufacturing – wafer temperature control with simultaneous multi-point monitoring

• Research & development – dynamic thermal analysis and transient studies requiring time-correlated data

• HVAC – multi-zone temperature monitoring with phase-accurate measurements

• Food processing – oven and sterilization chamber temperature profiling

Competitor Comparison

The DS3820SMTD is the simultaneous-sampling temperature input module – capturing all 4 channels at the exact same instant with 200 Hz speed. Compared to the sequential DS3820PSFA1B1A (also 200 Hz), it eliminates phase delays between channels (up to 5° in sequential modules) – essential for thermal profiling and dynamic analysis. Against standard 10 Hz sequential modules, it offers superior speed (20× faster), simultaneous sampling, and phase accuracy. For applications requiring time-correlated, high-speed temperature measurements, the DS3820SMTD delivers the best-in-class solution.

Selection Tips

• Choose DS3820SMTD when you need simultaneous, high-speed temperature measurements (up to 200 Hz) for thermal profiling, dynamic analysis, or phase-sensitive applications.

• Ideal for oven profiling, engine testing, turbine monitoring, induction heating, and R&D applications.

• For maximum speed (200 Hz), disable input filtering – enabling 50/60 Hz rejection reduces sampling rate.

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

• For 2-wire sensors, lead resistance adds error – use 3-wire or 4-wire for accurate measurements.

• Not suitable for Pt1000, Ni RTDs, or thermocouples – use dedicated modules.

• Ensure your PLC/DCS can handle the simultaneous data throughput from DS3820SMTD at 200 Hz.

Precautions

• Sampling rate vs. filtering: Maximum 200 Hz achieved with filtering disabled. Enable filtering only if noise rejection is required – it will reduce the sampling rate.

• Simultaneous sampling – all channels are sampled at the same instant; ensure all sensors are properly connected before starting acquisition.

• Lead resistance: For 2-wire sensors, lead resistance directly adds error – use 3-wire or 4-wire for accurate measurements. The DS3820SMTD compensates for 3-wire/4-wire automatically.

• Excitation current: Higher currents (1 mA) produce self-heating errors in small Pt100 elements – use 0.1 mA or 0.5 mA for sensitive sensors.

• Wiring: Use shielded twisted-pair cables; ground shield at module end only. High-speed simultaneous sampling is more susceptible to noise – ensure proper shielding and separation from power cables.

• Data throughput: 200 Hz × 4 channels × 24-bit data requires significant communication bandwidth – ensure your PLC/DCS can process the data rate.

• Signal-loss detection: Requires minimum sensor impedance – very low-impedance sensors may not trigger detection.

• Power sequencing: Apply backplane power before field power.

• Calibration: Perform periodic calibration using precision resistors to maintain accuracy – high-speed operation may accelerate drift.

• Spare: Keep one spare DS3820SMTD for critical high-speed loops – the simultaneous-sampling variant may have longer lead times.