Cognesense - Measure, Monitor, Protect

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 RF Capacitance Point Level Switch

Details

The Captrol 511 uses RF capacitance sensing with driven-guard circuitry, allowing it to ignore conductive coatings and buildup on the probe. This ensures reliable switching even in slurries, viscous materials, and powder applications.

The solid-state design contains no moving parts, eliminating common mechanical failures and reducing maintenance requirements. Its universal power supply simplifies installation across different plant power systems.

With adjustable sensitivity and selectable time delay, technicians can fine-tune switching performance to match specific process conditions, preventing false trips caused by turbulence, vibration, or splashing.

The fail-safe relay mode ensures predictable behavior during power loss, helping protect pumps and prevent spills.

Multiple probe designs are available, including Teflon®, stainless steel, ceramic, and abrasion-resistant materials, making the Captrol 511 suitable for abrasive solids, aggressive chemicals, sanitary processes, and high-temperature environments. Remote grounding options are available for installations in non-metallic vessels.

Designed for heavy-duty industrial use, the Captrol 511 performs reliably in chemical processing, food production, water and wastewater treatment, grain and powder handling, and general industrial process vessels.

Applications

Material Buildup: Driven-guard RF technology ensures reliable switching even when sticky or viscous materials coat the probe.
Light Solids and Powders: High-sensitivity RF sensing allows reliable detection even in low-density materials.
Non-Metallic Tanks: External ground reference capability enables accurate measurement in plastic or fiberglass tanks where the vessel wall cannot serve as a ground reference.
Pump Protection: Fail-safe relay modes protect pumps and prevent spills by ensuring dependable overflow and dry-run protection logic.

Technical Specifications

Parameter

Description

Technology

RF capacitance point-level switch with driven-guard probe

Power Supply

115 VAC, 230 VAC, or 24 VDC

Output

DPDT relay, 5 A

Sensitivity

Adjustable from 0.5 pF to 30 pF

Fail-Safe Modes

Selectable high-level or low-level operation

Time Delay

Adjustable from 0.3 to 20 seconds

Temperature / Pressure Ratings

Electronics: –40 °C to +71 °C; probes rated up to 400 psi

Enclosure

Explosion-proof cast aluminum housing

Enclosure Ratings

NEMA 4, 5, 7, 9, 12

Hazardous Area Approvals

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

Mounting

NPT or flange connection

Probe Types

Stainless steel, Teflon®, ceramic, and abrasion-resistant probes with remote ground options

Indicators

Dual LEDs for capacitance state and relay state

2026 COST ESTIMATE

Support

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

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?

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?

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?

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?

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?

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?

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

What applications is the Captrol 511 best suited for?

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

What happens during a power failure?

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

What probe options are available?

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