GE DS3820SMTU

Key Parameters

• Channels: 4 analog inputs with simultaneous sampling

• Sensor Types: Pt100 (2-wire, 3-wire, or 4-wire) OR Thermocouple (J, K, T, E, R, S, B, N) – software-configurable per channel

• Resolution: 24-bit ADC

• Accuracy:

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

  • Thermocouple: ±0.04% + ±0.4°C (K-type, 25°C)

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

• Cold-Junction Compensation: Built-in per channel (thermocouple mode)

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

• Measurement Range: –200°C to +850°C (Pt100); TC range per type

• 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: Enhanced CMRR > 120 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, CJC sensor fault, per-channel LED status

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

• Terminal Type: Spring-clamp (tool-free, vibration-resistant) – per suffix “U”

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

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

Advantages

• Universal sensor support – accepts both Pt100 RTDs and thermocouples; single module covers all common temperature sensors.

• Spring-clamp terminals – tool-free push-in wiring; reduces installation time; highly resistant to vibration loosening – critical for transportation, marine, and heavy industrial applications.

• 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.

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

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

• 24-bit resolution – provides superior measurement fidelity for both RTD and TC sensors.

• Per-channel configurability – each channel independently set for RTD or thermocouple type; no hardware changes required.

• Built-in CJC – for thermocouples; no external reference needed.

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

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

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

• Reduced spare parts – one module covers multiple sensor types.

Applications

• Mixed-sensor thermal profiling – plants with both RTD and thermocouple sensors requiring simultaneous high-speed monitoring

• Transportation & rail – simultaneous bearing (RTD) and exhaust (TC) temperature monitoring with vibration-resistant wiring

• Marine & offshore – engine room temperature monitoring with mixed sensor types in high-EMI environments

• Engine testing – simultaneous exhaust (TC) and component (RTD) temperature monitoring in automotive and aerospace

• Turbine monitoring – high-speed temperature profiling in power generation with mixed sensor types

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

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

• Research & development – dynamic thermal analysis with mixed sensor types requiring time-correlated data

Competitor Comparison

The DS3820SMTU is the flagship universal temperature input module – combining universal sensor support, simultaneous sampling, 200 Hz speed, enhanced EMI protection, and spring-clamp wiring. Compared to the Pt100-only DS3820SMTS, it adds thermocouple support while maintaining the same simultaneous sampling, speed, and EMI resilience – the ultimate flexibility for mixed-sensor applications. Against the universal DS3820PMMB (50 Hz sequential), it offers 4× faster sampling, simultaneous sampling (eliminating phase errors), and superior EMI protection. For applications requiring maximum flexibility, speed, and precision in harsh environments, the DS3820SMTU delivers the best-in-class solution.

Selection Tips

• Choose DS3820SMTU when you need universal sensor support (Pt100 + TC), simultaneous high-speed sampling (up to 200 Hz), enhanced EMI protection, and vibration-resistant spring-clamp wiring – the ultimate all-in-one temperature input module.

• Ideal for transportation, marine, engine testing, turbine monitoring, induction heating, R&D, and mixed-sensor thermal profiling applications.

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

• Verify the sensor type and wire configuration for each channel – software-configurable per channel.

• Confirm spring-clamp terminals accept your wire gauge (typically 0.2–2.5 mm² / 24–14 AWG) and consider using ferrules for stranded wire.

• For RTDs, use 3-wire or 4-wire for accurate measurements (2-wire adds lead resistance error).

• For thermocouples, use the correct extension wire type – standard copper wire introduces errors.

• Ensure your PLC/DCS can handle the simultaneous data throughput from DS3820SMTU at 200 Hz.

Precautions

• Wire preparation: Use only solid or stranded wire with proper ferrule termination – bare stranded wire may not make reliable contact in spring-clamp terminals.

• Wire insertion: Insert wire fully into the spring-clamp opening until it stops; pull gently to verify secure connection.

• Sensor selection: Each channel must be configured for either RTD or TC mode – ensure correct selection before operation.

• 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.

• RTD lead resistance: For 2-wire RTDs, lead resistance directly adds error – use 3-wire or 4-wire for accurate measurements. The DS3820SMTU compensates for 3-wire/4-wire automatically.

• Thermocouple CJC: Position the DS3820SMTU away from drafts and heat sources – CJC errors affect TC accuracy.

• Excitation current (RTD): Higher currents (1 mA) produce self-heating errors – 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.

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

• Power sequencing: Apply backplane power before field power.

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

• Spare: Keep one spare DS3820SMTU for critical high-speed loops – the universal, simultaneous-sampling variant may have longer lead times. Also stock replacement ferrules for spring-clamp terminals.