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Captrol 511

RF Capacitance Point Level Switch

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Captrol 511

The Captrol 511 is designed for process engineers, plant operators, maintenance teams, and OEM system integrators who require a reliable and rugged point-level solution for powders, slurries, and liquids.

The device uses solid-state RF capacitance technology combined with universal power input, adjustable time delay, and a driven-guard probe design that prevents false trips caused by product buildup.

Unlike many competitive point-level switches, the Captrol 511 features explosion-proof construction, integral electronics with high dielectric sensitivity, and durable probe options, providing dependable performance in both metallic and non-metallic vessels operating in harsh industrial environments.

Captrol 511
Captrol 511 RF Capacitance Point Level Switch
Captrol 511

Features

Driven-Guard Probe Design

Prevents false signals caused by coating or buildup, enabling dependable switching in sticky, viscous, or fouling media without requiring frequent probe cleaning.

Universal Power Compatibility

Accepts 115/230 VAC or 24 VDC without hardware changes, simplifying commissioning, stocking, and replacement across diverse plant power standards.

Adjustable Sensitivity & Delay

Allows tuning for powders, liquids, or turbulent surfaces, avoiding nuisance trips from agitation, splashing, aeration, or vibration in process vessels.

Explosion-Proof Construction

Cast aluminum housing rated NEMA 4/5/7/9/12 protects electronics in hazardous locations, ensuring safe operation in classified industrial process areas.

Fail-Safe High/Low Selection

Selectable fail-safe logic ensures the system reverts to a predictable, safe relay state during power loss or wiring faults, protecting pumps and tanks.

Multiple Probe Material Options

Stainless, Teflon®, ceramic, and abrasion-resistant probes provide chemical, temperature, or mechanical durability, adapting the sensor to challenging media.

Applications

  • Powders & Granular Solids: RF capacitance detects low-density powders missed by mechanical switches, delivering stable point-level indication in dusty or low-DK materials.
  • Sticky or Coating Liquids: Driven-guard circuitry rejects buildup effects, ensuring reliable switching even when viscous or coating liquids adhere to the probe surface.
  • Chemical Storage Tanks: Dielectric-independent RF operation maintains calibration in changing chemical compositions, providing accurate switching without drift or recalibration.
  • Pump Control Protection: Dual-state relay logic supports overflow or dry-run protection, allowing pumps to be automatically started or stopped based on level.
  • Hazardous Area Operation: Explosion-proof aluminum enclosure enables safe installation in Class I and II areas where ignition sources must be fully contained.
  • Moisture-Rich Conductive Media: Low-sensitivity calibration mode provides stable switching in wet, conductive, or high-moisture materials that commonly cause false trips in mechanical devices.
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Specifications

Technology

RF capacitance point-level switch with driven-guard probe

Power Supply

115 VAC, 230 VAC, or 24 VDC

Output

5 A DPDT relay

Sensitivity

0.5 pF to 30 pF

Fail-Safe Modes

Selectable high-level / low-level

Time Delay

Adjustable (0.3–20 seconds)

Electronics Temperature Limits

–40 °C to +70 °C

Probe Pressure & Temperature

up to 400 psi / high-temp options available

Enclosure

Explosion-proof cast aluminum; NEMA 4, 5, 7, 9, 12

Enclosure Approvals

NEC Class I Div II (C, D) Class II Div II (E, F, G)

Mounting

NPT or flange options

Probe Options

Stainless steel, Teflon, ceramic, abrasion-resistant options Various insertion lengths; remote ground plates available for plastic tanks

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

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Does the Captrol 511 work with sticky or coating materials?

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Yes — the driven-guard probe prevents false trips caused by buildup, slurry coating, or thick media.

How does the Captrol 511 prevent false trips when the probe becomes coated?

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The driven-guard probe design is the key. It creates an electronic shield that prevents conductive buildup or coating on the probe from generating a false signal. The switch only actuates when the bulk material fills the sensing area, ensuring reliable level indication and significantly reducing service calls for cleaning.

Can it be installed in hazardous areas?

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Absolutely. The 511 is explosion-proof and approved for Class I & II Div II industrial environments.

Can this switch operate in both AC and DC systems?

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Yes. The Captrol 511 features a universal power supply that allows it to operate on 115 VAC, 230 VAC, or 24 VDC input. This simplifies stocking and installation across sites with varied power standards.

What is the purpose of the adjustable time delay?

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The adjustable time delay allows you to set how long the switch must detect the presence or absence of the product before the relay actuates. This is essential for challenging applications with agitation or splashing, as it prevents spurious switching that could unnecessarily trip a pump or alarm.

Is calibration difficult?

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No. The 511 features adjustable sensitivity and time delay for quick setup and reliable performance.

Can the device be used in plastic or fiberglass tanks?

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Yes — it supports external or remote ground references for non-metallic vessels.

What applications is the Captrol 511 best suited for?

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Ideal for powder hoppers, slurry tanks, chemical vessels, food processing tanks, and wastewater basins.

What happens during a power failure?

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Selectable fail-safe logic ensures the relay returns to a safe state on power loss.

What probe options are available?

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Choose from Teflon®, ceramic, stainless-steel, and abrasion-resistant probes for chemical, high-temp, or abrasive media.

Summary

With proven RF capacitance measurement technology, explosion-proof construction, and driven-guard probe engineering, the Captrol 511 is a robust, maintenance-friendly point-level switch ideal for powders, slurries, and liquids. It delivers dependable level detection across demanding industrial applications — reducing false trips, protecting pumps and storage systems, and delivering long-life performance even in sticky, aggressive, or abrasive media. Our legacy of RF capacitance innovation ensures the Captrol 511 delivers reliable protection, process control, and peace of mind in mission-critical operations.

L&J
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