GE DS3820HSMC

Key Parameters

• Channels: 8 independent counter/timer channels

• Input Type: 24 V DC (single-ended) or 5 V differential (RS-422) – software-selectable per channel

• Maximum Input Frequency: 1 MHz per channel (with filtering disabled)

• Resolution: 32-bit counter per channel

• Timer Resolution: 1 µs (microsecond)

• Modes: Event counting, frequency measurement, period measurement, pulse-width measurement, quadrature decoding (x1/x2/x4), PWM output, one-shot timing, periodic timing

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

• Output: PWM or pulse train output (up to 1 MHz, 16-bit resolution) per channel

• Diagnostics: Per-channel LED status, over-range detection, count-lost detection

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

• Power: 24 V DC backplane power, ≤4 W (plus external field supply for inputs/outputs)

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

• Terminals: Screw-type (suffix-dependent)

Advantages

• 8 independent high-speed channels – eight 1 MHz channels in a single slot; highest density in the family.

• Versatile multi-mode operation – supports counting, quadrature decoding, frequency, period, pulse-width, PWM output, and timing – all in one module.

• High 1 MHz frequency – supports high-resolution encoders, high-speed flowmeters, and precision timing applications.

• Flexible input configuration – each channel independently set for 24 V single-ended or 5 V differential (RS-422) input.

• Integrated PWM/pulse output – each channel can generate PWM or pulse train output up to 1 MHz; eliminates separate output modules.

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

• 1 µs timer resolution – precision timing for event scheduling and period measurement.

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

• 32-bit counters – eliminates rollover concerns for most industrial applications.

Applications

• Multi-axis motion control – reading quadrature encoders on multiple servo/stepper axes

• Precision timing – event scheduling, period measurement, and pulse generation for test systems

• High-speed flow measurement – counting pulses from turbine flowmeters with frequency up to 1 MHz

• Speed monitoring – frequency measurement from proximity sensors on high-speed rotating shafts

• PWM control – generating PWM signals for speed control, heating control, and dimming

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

• Printing presses – registration control with quadrature encoders

• Semiconductor manufacturing – precision wafer handling and stage positioning

• Test & measurement – pulse generation and period measurement for equipment calibration

Competitor Comparison

The DS3820HSMC is the flagship counter/timer module – offering eight 1 MHz channels with PWM/output capability in a single slot. Compared to the 4-channel DS3820FE1A1B1B, it doubles channel count, doubles frequency (1 MHz vs. 500 kHz), adds PWM/pulse output capability, and includes 1 µs timer resolution – all at a lower per-channel cost. Against competitor 8-channel counter modules, the DS3820HSMC offers superior versatility (quadrature, PWM, timing) and input flexibility (24 V or 5 V differential) at a competitive price. For advanced motion control, precision timing, and high-speed measurement applications, the DS3820HSMC delivers the most comprehensive and cost-effective solution.

Selection Tips

• Choose DS3820HSMC when you need multiple high-speed counter/timer channels with PWM output capability – the ultimate all-in-one motion and timing module.

• Ideal for multi-axis motion control, precision timing, high-speed flow measurement, and PWM control applications.

• Verify the input type matches your sensors – supports 24 V single-ended or 5 V differential (RS-422) per channel.

• Consider the PWM output rating – 24 V DC, 0.5 A per channel; use external drivers for higher current loads.

• Not suitable for absolute encoders (SSI, BiSS, EnDat) – use dedicated absolute encoder modules.

• Ensure your PLC/DCS can handle the data throughput from eight high-speed channels.

Precautions

• Frequency limits: Maximum 1 MHz achieved with filtering disabled. Enable filtering only if necessary – it reduces maximum frequency.

• Input configuration: Each channel independently configurable for 24 V single-ended or 5 V differential – set correctly before operation.

• Differential wiring: Use twisted-pair shielded cables for differential inputs (A+/A-, B+/B-, Z+/Z-). Maintain proper cable twist for noise rejection.

• Cable length: Differential mode supports up to 100 m with proper shielding; single-ended mode supports up to 30 m.

• PWM output: For PWM applications, ensure output load does not exceed 0.5 A – use external relays or amplifiers for higher loads.

• Inductive loads: Use external flyback diodes for inductive loads driven by PWM outputs to prevent back-EMF damage.

• Power: Requires external 24 V field supply for inputs and outputs – ensure supply capacity for all channels.

• Grounding: Ground shield at module end only to avoid ground loops.

• Configuration: Set mode and input type before enabling the channel – changing modes during operation may cause count discontinuity.

• Spare: Keep one spare DS3820HSMC for critical motion/timing applications – the high-channel-count feature set may have longer lead times.