Cognesense - Measure, Monitor, Protect

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 RF Capacitance Point Level Switch

Applications

Powders and Bulk Solids: RF capacitance sensing reliably detects low-dielectric materials, performing effectively even below 10 lb/ft³ bulk density, where many other switches struggle.
Sticky or Coating Liquids: The driven guard design maintains signal integrity and prevents false trips caused by conductive buildup on the probe.
Chemical Storage: The microcontroller maintains accuracy across varying dielectric properties, and probe options in Teflon® or Kynar® provide corrosion resistance.
Pump Control and Overflow Protection: Fast relay actuation provides dependable protection against tank overflows or pump dry-run conditions.

Technical Specifications

Parameter

Specification

Technology

Microcontroller-based RF capacitance point level switch

Mounting Options

Integral or remote mounting (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

Less than 3 VA

Output

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

Frequency

50–60 Hz

Sensitivity Range

Adjustable from 0.5 pF to 10 pF

Response Time

Adjustable from 0.1 to 30 seconds

Fail-Safe Mode

Field selectable for high or low level

Electronics Temperature Limits

–40 °F to +160 °F (–40 °C to +71 °C)

Probe Temperature Limits

–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

Enclosure Ratings

NEMA 4, 5, 7, 8, 12

Hazardous Area Ratings

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

Probe Styles

GIMF (Fortron®), GIMN (Noryl®), GT/GTH (Teflon®), GC (Ceramic), GFC (Flexible cable), GAR (Abrasion-resistant stainless steel)

Accessories

Sensitivity sleeves, flange adapters, 90° bends, lagging extensions

Calibration

One-touch Auto-Cal pushbutton (no tools required)

2026 COST ESTIMATE

Support

If you have a question that is not covered here, please contact the Cognesense support team for assistance.

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?

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?

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?

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?

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?

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

What probe styles are available?

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?

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?

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.