GE DS3820LIMC

Key Parameters

• Channels: 4 analog outputs

• Output Type: 4–20 mA (current loop)

• Loop Power: Internal 24 V DC, 30 mA per channel (loop-powered; no external supply needed for 2-wire devices)

• Output Resolution: 16-bit (0.0015% of full scale)

• Accuracy: ±0.06% of full scale (25°C); ±0.2% over –40°C to +85°C

• Loop Resistance: Maximum 600 Ω (at 24 V internal supply)

• Settling Time: < 5 ms (to 0.1% of final value)

• Diagnostics: Per-channel short-circuit detection, open-wire detection, over-temperature alarm, per-channel LED status

• Fail-Safe States: Software-configurable per channel (hold last value, go to 4 mA, go to 20 mA, or user-defined preset) on communication loss

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

• Operating Temperature: –40°C to +85°C (extended range vs. standard –40°C to +70°C)

• Power: 24 V DC backplane power, ≤4 W (logic + internal loop power)

• Terminals: Screw-type (suffix-dependent)

Advantages

• Extended temperature range – operates reliably in extreme ambient conditions (up to +85°C); ideal for outdoor, desert, or unheated enclosures.

• Integrated loop power – internal 24 V loop power per channel; eliminates external power supplies for 2-wire transmitters and smart devices.

• High 16-bit resolution – provides precise analog control for demanding process applications.

• Open-wire detection – detects broken output wiring or disconnected loads; alerts operators for proactive maintenance.

• Per-channel short-circuit protection – auto-restart protection; eliminates external fuses and reduces downtime.

• Software-configurable fail-safe – define output behavior (hold, 4 mA, 20 mA, or preset) on communication loss for safe system shutdown.

• Fast settling time – < 5 ms for dynamic control loops.

• High channel density – 4 outputs in a single slot; saves rack space.

• LED status indicators – per-channel visual indication for quick troubleshooting.

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

• Optical isolation – protects backplane from field transients.

Applications

• Oil & gas pipelines – VFD speed control and valve positioning in desert (hot) or arctic (cold) locations

• Outdoor power substations – process setpoint control in direct sunlight or extreme cold

• Steel mills & foundries – analog control near high-heat zones

• Wind turbines – pitch and yaw control with extended temperature rating

• Marine & offshore – engine room control in high-temperature environments

• VFD speed control – providing 4–20 mA reference signals to variable frequency drives

• Proportional valve control – precise positioning of hydraulic and pneumatic valves

• Process control – setpoint output for temperature, pressure, and flow controllers

• Smart transmitter communication – powering and controlling HART-enabled smart transmitters

Competitor Comparison

The DS3820LIMC is the extended-temperature variant of the high-resolution current-output family. Compared to the standard DS3820LIMB, it offers a wider operating range (up to +85°C) – critical for harsh environments – while maintaining integrated loop power, 16-bit resolution, and comprehensive diagnostics. Against standard 12-bit output modules, the DS3820LIMC provides 16× finer resolution, eliminates external loop power supplies, and adds open-wire detection and per-channel fail-safe configuration – all with extended temperature capability. For demanding 4–20 mA process control applications in extreme environments, the DS3820LIMC delivers the most comprehensive and ruggedized solution.

Selection Tips

• Choose DS3820LIMC when you need high-precision 4–20 mA outputs with integrated loop power and extended temperature operation (–40°C to +85°C).

• Ideal for oil & gas, outdoor substations, steel mills, wind turbines, and marine applications.

• Verify the loop resistance does not exceed 600 Ω per channel – the internal 24 V supply supports up to 600 Ω at 20 mA.

• Consider the fail-safe behavior – configure each channel for the safe state (4 mA, 20 mA, hold, or preset) on communication loss.

• Note the slight accuracy reduction at extreme temperatures (±0.2% vs. ±0.15% for standard range) – a trade-off for extended operation.

• Not suitable for 0–10 V voltage-output devices – use the DS3820LFRA variant for voltage outputs.

• Ensure your PLC/DCS can read and process diagnostic data from the DS3820LIMC.

Precautions

• Temperature derating: At sustained +85°C ambient, ensure adequate airflow – the DS3820LIMC dissipates up to 4 W and may require forced cooling in dense racks.

• Loop resistance: Do not exceed 600 Ω per channel (including wiring and load). Higher resistance may cause output current saturation.

• Wiring: Use shielded twisted-pair cables for analog outputs to reduce EMI. Ground shield at module end only.

• Inductive loads: The DS3820LIMC is not designed for direct inductive loads – use external buffers or isolators for inductive actuators.

• Fail-safe testing: Test fail-safe behavior during commissioning – confirm outputs go to the desired state on communication loss.

• Open-wire detection: Requires a minimum load current – very high-impedance loads (>1 MΩ) may not trigger open-wire detection.

• Loop power capacity: Each channel provides 24 V, 30 mA – ensure total loop current does not exceed 30 mA.

• HART compatibility: Supports HART communication – ensure proper impedance (250 Ω) for HART modem connection.

• Grounding: Maintain proper grounding to avoid ground loops that could affect output accuracy.

• Calibration: Perform periodic calibration using a precision current meter to maintain accuracy – extended temperature operation may accelerate drift.

• Spare: Keep one spare DS3820LIMC for critical control applications – extended-temperature modules typically have longer lead times.