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Captrol 500

RF Capacitance Point Level Switch

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Captrol 500

The Captrol 500 is designed for process engineers, plant safety personnel, and operators who need a dependable, low-maintenance level switch for liquids, powders, or bulk solids.

The device uses microcontroller-based RF capacitance switching combined with one-touch calibration, fail-safe operation, and universal power compatibility.

Unlike competitive point level switches that require tools or manual trim-pot adjustments, the Captrol 500 features Auto-Cal one-button setup, built-in self-diagnostics, and a driven-guard probe design that eliminates false trips caused by coating or buildup. These features make it one of the most reliable and easy-to-use level switches available.

Captrol 500
Captrol 500 RF Capacitance Point Level Switch
Captrol 500

Features

One-Touch Auto-Cal

Fast, tool-free calibration eliminates multi-step adjustments, allowing operators to commission the switch quickly without test equipment or expert tuning.

Driven-Guard Probe Design

The guard energizes a field around coating buildup, preventing conductive films from influencing the measurement and ensuring stable switching in fouling applications.

Microcontroller-Based RF Sensing

Provides drift-free, repeatable switching with high immunity to electrical noise, dielectric changes, and environmental variations.

Universal Power Input

Accepts 115/230 VAC or 24 VDC, enabling one model to operate globally and reducing stocking complexity across multiple facilities.

Selectable Fail-Safe Mode

Allows users to choose energized-on-rise or energized-on-fall, ensuring predictable behavior during power loss or wiring faults.

Adjustable Sensitivity & Delay

Fine-tunes response for powders, foams, and viscous liquids, with delay settings that prevent nuisance trips from splashing or turbulence.

Applications

  • Powders & Bulk Solids: Detects low-DK powders reliably using RF capacitance, avoiding false trips common with mechanical probes in light-density materials.
  • Sticky or Coating Liquids: Driven-guard design rejects buildup, ensuring accurate switching even when viscous or conductive films accumulate on the probe.
  • Chemical Storage Tanks: Maintains calibration stability despite dielectric changes, providing dependable level indication for corrosive or varying-composition liquids.
  • Pump & Overflow Control: Provides fast, reliable relay actuation to protect pumps from dry-run conditions or prevent tank overfill during filling operations.
  • Hazardous or Remote Locations: Explosion-proof housing and remote electronics enable ground-level calibration without climbing tanks or opening energized enclosures.
  • Non-Metallic Vessel Monitoring: Supports installations in fiberglass, plastic, or concrete tanks using an external ground reference placed parallel to the probe.
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Specifications

Technology

Microcontroller-based RF capacitance point level switch

Mounting Options

Integral or Remote (up to 50 ft cable)

Power Supply

115 VAC (95–135 V), 230 VAC (180–270 V), or 24 VDC (18–28 V)

Power Consumption

< 3 VA

Output

SPDT or DPDT relay (5 A @ 115/230 VAC, 3 A @ 26 VDC, non-inductive)

Frequency

50–60 Hz

Sensitivity Range

Adjustable 0.5 pF to 10 pF

Response Time

Adjustable 0.1 to 30 seconds

Fail-Safe Mode

Field selectable—High Level or Low Level

Temperature Limits

  • Electronics: –40 °F to +160 °F (–40 °C to +71 °C)
  • Probes: –40 °F to +450 °F (–40 °C to +232 °C) depending on model

Pressure Limits

  • Standard probes: up to 500 psi (3.4 MPa)
  • Teflon® probes: up to 400 psi (2.8 MPa)

Indicators

  • Green LED: Probe capacitance above setpoint
  • Red LED: Relay energized

Housing

Cast aluminum, explosion-proof, NEMA 4, 5, 7, 8, 12

Enclosure Hazardous Area Ratings

NEC Class I, Groups C & D; Class II, Groups E, F, G

Probe Styles

GIMF – Guarded Injection Molded Fortron GIMN – Guarded Injection Molded Noryl (food-grade) GT / GTH – Guarded Teflon® (316 SS or Hastelloy center rod) GC – Guarded Ceramic (up to 750 °F) GFC – Flexible Cable Probe (up to 25 ft) GAR – Guarded Abrasion Resistant Stainless Steel

Accessories

Sensitivity sleeve, flange adapters, 90° probe bends, lagging extensions

Calibration

Auto-Cal pushbutton; no tools required

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If you have questions not covered here, please contact the Cognesense support team for assistance.

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What makes the Captrol 500 different from other level switches?

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It uses a microcontroller-based RF capacitance design with one-touch Auto-Cal calibration, eliminating manual tuning and ensuring drift-free, maintenance-free performance.

What is the benefit of the one-touch Auto-Cal feature?

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The Auto-Cal feature drastically simplifies setup by automatically setting the correct trip point for the current material conditions. Technicians only need to press a button to calibrate the switch—eliminating the tedious, error-prone process of manually adjusting multiple trim pots with meters and tools.

Can it handle coating or sticky materials?

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Yes. The driven guard probe design prevents false trips caused by buildup or conductive coating, even in viscous or adhesive media.

Is it suitable for hazardous environments?

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Absolutely. The Captrol 500 is explosion-proof and rated for Class I & II hazardous locations (NEC Groups C, D, E, F, G).

How is calibration performed?

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Just press the Auto-Cal button—no tools or meters required. Calibration takes seconds and is automatically stored by the microcontroller.

What power options are available?

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The switch accepts 115/230 VAC or 24 VDC power, simplifying plant standardization and inventory.

What probe styles are available?

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Choose from a wide range of Teflon®, ceramic, stainless steel, Noryl®, or flexible cable probes for any process or temperature condition.

Can the Captrol 500 be used for both high and low-level detection?

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Yes. The switch’s fail-safe mode can be field-selected for either high-level or low-level operation.

How does the driven guard design prevent false alarms?

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In capacitance switches, conductive buildup (like sticky liquids) on the probe can look like the actual product, causing false alarms. The driven guard is an insulated sleeve around the probe’s center rod that electronically shields the sensing element from this buildup, ensuring only the true presence of bulk product triggers the switch.

Summary

The Captrol 500 brings modern microcontroller precision and effortless one-touch calibration to RF capacitance point level control. With flexible mounting, wide probe selection, and proven explosion-proof reliability, it delivers superior accuracy and uptime for liquid, slurry, and solid applications across chemical, food, wastewater, and energy industries. 

Combining durability, simplicity, and intelligence, the Captrol 500 sets the benchmark for safe, low-maintenance level detection and switching.

L&J
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