Captrol 520

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Overview

Captrol 520

For refinery and chemical plant operators, wastewater and industrial process engineers, and OEM equipment designers who require reliable point-level detection in challenging tanks, silos, pits, and bulk storage applications, the Captrol 520 delivers proven RF capacitance switching, universal power input, and rugged probe configurations up to 250 ft.
Unlike mechanical floats, optical sensors, or vibrating forks that foul, drift, or fail in viscous, abrasive, or sticky media, the Captrol 520 uses high-frequency RF technology, coating-rejection circuitry, and independent calibration controls to ensure accurate, repeatable switching—even in low-dielectric liquids, powders, sludge, and slurries.

With fail-safe protection, adjustable time delay, and explosion-proof construction, the Captrol 520 is an ideal point-level solution for overflow protection, pump control, dry-run protection, and safety shutdowns across oil & gas, chemical, water treatment, food, and industrial applications.

Omnitrols 610/710

Features

Non-Contact Technology

RF Capacitance Sensing (2 MHz)

Accurate switching in liquids, slurries, and powders—even low-dielectric media.

Coating-Rejection Electronics

Prevents false alarms in sticky or viscous materials.

Ultra-Low Power

Universal Power Input (115/230 VAC or 24 VDC)

One device fits global plant power standards—ideal for retrofits and spares reduction.

Selectable Fail-Safe Modes

Ensures correct alarm/shutdown behavior during power loss or wiring faults.

Tank-Side Automation

Probes up to 250 ft

Supports tall silos, deep wells, sumps, and large process tanks.

Graphite Displacer Reliability

Explosion-Proof Housing

Rated for hazardous Class I & II industrial environments.

Time Savings

Adjustable Time Delay

Filters agitation, surges, and splashing for reliable switching.

LED Status Indicators

Provides clear visual feedback for commissioning and troubleshooting.

Details

The Captrol 520 applies RF capacitance principles to detect material presence by measuring dielectric change between the probe and vessel. A driven-guard design and coating-rejection circuitry ensure the switch remains accurate even when buildup occurs—eliminating common causes of nuisance trips and maintenance shutdowns.
Universal AC/DC power compatibility simplifies stocking and field upgrades, while fail-safe relay logic ensures safe behavior for overflow, pump protection, and shutdown systems.
Engineered for harsh process environments, the Captrol 520 includes explosion-proof enclosures, corrosion- and abrasion-resistant probe options, and high-temperature / high-pressure capabilities. Flexible mounting designs—including rigid, cable, and heavy-duty probes—enable installation in chemical vessels, wastewater pits, bulk powder silos, and abrasive media transfer systems.
Built with decades of RF sensing expertise, the Captrol 520 provides low-maintenance, long-life point level protection across mission-critical industrial operations.

Technical Specifications

Parameter Specification
Sensing Technology
RF capacitance, ~2 MHz
Power Input
115 VAC (95–135 V), 230 VAC (180–270 V), or 24 VDC (18–28 V)
Consumption
< 3 VA
Outputs
Up to 2 DPDT relays (independent)
Load Rating
5 A @115 VAC; 2.5 A @230 VAC; 3 A @26 VDC (non-inductive)
Sensitivity
Adjustable; liquids ≥ 1.5 ε & solids ≥ 10 lb/ft³
Stability
0.01 % / °F thermal stability
Time Delay
Fast response + 50 ms–10 sec adjustable
Electronics Temp
–40 °F to +160 °F (–40 °C to +71 °C)
Probe Rating
Up to 450 °F / 400–500 psi (probe-dependent)
Enclosure
NEMA 4, 5, 7, 9, 12
Hazardous Rating
NEC Class I C&D; Class II E/F/G
Probe Types
Rigid, flexible cable, Teflon®, Kynar®, stainless, Hastelloy
Probe Length
Up to 250 ft
Mounting
¾″ NPT or flanged

Documents and Downloads

Product Flyer

Have a look at the flyer to get all the tech specs and product features. Brochure

User Manual

Read the manual for detailed information and instructions. Manual

Calibrations

Check out a sample cert from our calibration lab. Certificate

Contact Support

If you have a question that we have not covered then just get in touch and we’ll be happy to help.

Contact Us

FAQs

We have tried to answer the most common questions we are asked here.

Its 2 MHz RF sensing and coating-rejection circuitry ensure accurate switching even with buildup, foam, or low-dielectric materials.

Yes. The RF capacitance technology in the Captrol 520 is highly versatile. It’s sensitive enough to detect level changes in liquids (dielectric constant above 1.5) and is also effective for many bulk solids and powders (bulk density >10 lb/ft3).

Yes — the housing is explosion-proof and approved for Class I & II hazardous areas.

It accepts 115 VAC, 230 VAC, or 24 VDC, making it easy to standardize across facilities.

Yes — dual-point logic and adjustable time delay allow reliable pump-on/pump-off control to prevent short-cycling and overflow.

The dual DPDT relays provide two completely independent switching circuits. This allows one Captrol 520 unit to handle two separate critical functions simultaneously, such as a high-level overflow alarm and a low-level pump shutoff, reducing the number of devices and tank penetrations required.

Probes are available up to 250 ft, ideal for tall silos and deep pits.

Yes — ground reference and probe options allow accurate sensing in non-metallic vessels.