GE DS3820CI2AG21C1A

Key Parameters

• Channels: 2 independent counter/encoder inputs

• Input Type: 24 V DC, differential or single-ended (software-configurable per channel)

• Maximum Input Frequency: 100 kHz per channel (with filter disabled)

• Resolution: 32-bit counter per channel

• Count Modes: Up/down counting, quadrature x1/x2/x4, frequency, period, pulse-width measurement

• Input Filtering: Software-selectable 0.1–10 ms debounce

• Differential Inputs: RS-422 compatible (A+, A-, B+, B-, Z+, Z-) for noise-immune long-distance encoder connections

• Auxiliary Power Output: Isolated 24 V DC, 100 mA (per channel or shared – check suffix) – eliminates separate power supply for encoders

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

• Terminal Type: 21-pin spring-clamp (tool-free, vibration-resistant) – per suffix “G21C”

• Diagnostics: Per-channel LED status, over-range detection, count-lost detection, auxiliary output short-circuit protection

• Power: 24 V DC backplane power, ≤3.5 W (including auxiliary output load)

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

Advantages

• Integrated auxiliary power output – provides isolated 24 V DC power for encoders/sensors; eliminates separate power supply, saves panel space and wiring.

• Spring-clamp terminals – tool-free push-in wiring; reduces installation time; highly resistant to vibration loosening.

• Differential inputs – superior noise immunity for long cable runs (up to 100 m); rejects common-mode noise.

• Dual high-speed counters – two independent 100 kHz channels in one slot; saves rack space.

• Versatile measurement modes – counting, quadrature decoding, frequency, period, and pulse-width all in one module.

• Quadrature x4 decoding – delivers 4× resolution from standard incremental encoders.

• Flexible input configuration – each channel independently set for differential or single-ended input.

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

Applications

• Position feedback – reading encoders on servo motors and conveyors with integrated sensor power

• Flow measurement – counting pulses from turbine flowmeters with long cable runs and powered directly from the module

• Speed monitoring – frequency measurement from proximity sensors with self-contained wiring

• Web handling – tension control and registration with encoder feedback

• Packaging machinery – product counting and cut-to-length positioning

• Wind turbines – speed and position monitoring with long cable runs from nacelle to controller

• Remote installations – where separate 24 V power for encoders is unavailable or costly

Competitor Comparison

The DS3820CI2AG21C1A is the fully integrated solution – combining differential inputs, spring-clamp wiring, and auxiliary power in one module. Compared to the screw-terminal DS3820CI2AD21C, it adds tool-free wiring and integrated encoder power, significantly reducing installation time and panel complexity. Against competitor setups requiring external power supplies, the DS3820CI2AG21C1A eliminates the cost and space of a separate 24 V power supply – a major advantage for remote or space-constrained panels. For plants standardizing on spring-clamp wiring, the DS3820CI2AG21C1A offers the most streamlined installation and lowest total installed cost.

Selection Tips

• Choose DS3820CI2AG21C1A when you want one module that handles encoder inputs, sensor power, and vibration-resistant wiring – the ultimate solution for new panels.

• Ideal for remote installations where separate 24 V power for encoders is not available.

• Perfect for high-vibration environments (transportation, marine, heavy machinery) where spring-clamp terminals prevent loosening.

• Verify encoder current draw does not exceed 100 mA – the DS3820CI2AG21C1A auxiliary output is current-limited.

• Confirm the spring-clamp terminals accept your wire gauge (typically 0.2–2.5 mm² / 24–14 AWG).

• Not suitable for encoders requiring more than 100 mA – use an external power supply and select a non-auxiliary-power version.

Precautions

• Auxiliary power capacity: Total current draw across all powered sensors/encoders must not exceed 100 mA – exceeding this will trip the short-circuit protection.

• Auxiliary power polarity: Double-check polarity when wiring encoders – reversed connections may damage the sensor (the DS3820CI2AG21C1A has reverse-polarity protection, but sensors may not).

• Differential wiring: Use twisted-pair shielded cables for each differential pair; maintain proper cable twist for noise rejection.

• Spring-clamp wire prep: Use only solid or stranded wire with proper ferrule termination – bare stranded wire may not make reliable contact.

• Frequency limits: Maximum 100 kHz achieved only with filtering disabled – enable filtering only if necessary.

• Cable length: Differential mode supports up to 100 m with proper shielding.

• Grounding: Ground shield at module end only to avoid ground loops. The auxiliary power output is isolated – do not tie its common to field ground unless necessary.

• Power sequencing: Apply backplane power before field power to avoid spurious counts.

• Spare: Keep one spare DS3820CI2AG21C1A for critical loops – the integrated features make it unique, with potentially longer lead times. Also stock replacement ferrules for spring-clamp terminals.