Cognesense - Measure, Monitor, Protect

Cap Analog 410

The Cap Analog 420 is designed for process engineers, control technicians, and plant maintenance teams who need continuous and reliable level measurement for liquids, slurries, and bulk solids, with the added flexibility of local or remote installation.

This remote RF capacitance transmitter combines continuous analog output, dual relay alarms, and universal power compatibility in a rugged, explosion-proof package.

Designed for harsh or hazardous environments, the Cap Analog 420 maintains accuracy even when coating, buildup, or dielectric changes occur. This performance is achieved through coating-rejection circuitry and temperature-stable electronics.

With its remote-mounted electronics enclosure, operators can calibrate and service the transmitter safely at ground level, up to 800 feet from the probe. This makes it ideal for tall silos, buried tanks, and confined installations.

Whether used in chemical processing, wastewater plants, or bulk material handling, the Cap Analog 420 provides a dependable, maintenance-free solution that integrates directly with plant control and alarm systems.

Cap Analog 420 RF Capacitance Level Transmitter

Applications

Remote or Inaccessible Tanks: Remote-mounted electronics allow easier service and calibration for tall tanks, buried vessels, or installations with limited access.
Slurries and Bulk Solids: RF capacitance sensing reliably detects level changes without the wear, sticking, or jamming issues common with mechanical switches.
Corrosive or Coating Liquids: Coating-rejection circuitry maintains measurement accuracy even when buildup occurs on the probe.
Process Alarms and Control: Dual SPDT relay outputs provide integrated high- and low-level alarms directly within the transmitter.

Technical Specifications

Parameter

Description

Measurement Technology

RF capacitance with remote transmitter and integral preamplifier

Output Signal

4–20 mA DC or 0–10 V DC (selectable)

Relay Outputs

2 × SPDT relays, independently adjustable; 5 A at 115 VAC (non-inductive)

Power Supply

115 VAC (90–135 V), 230 VAC (180–279 V), or 24 VDC (15–28 V)

Power Consumption

Less than 6 VA

Frequency

50–80 Hz

Fail-Safe Mode

Switch-selectable energized or de-energized on high level

Status Indicators

Dual LEDs: Red (capacitance above setpoint), Yellow (relay energized)

Electronics Temperature Range

–40 °F to +160 °F (–40 °C to +71 °C)

Zero / Span Range

Standard: 10–500 pF zero, 50–1,000 pF span; High-gain: 100–2,000 pF zero, 800–10,000 pF span

Temperature Stability

±0.5 pF per 30 °F at maximum sensitivity

Build-Up Tolerance

Up to 1,000 µmho conductivity

Cable Length (Probe to Electronics)

Up to 800 ft (244 m)

Process Connection

¾ in NPT standard; Tri-Clamp or flange options available

Housing (Preamplifier)

Cast aluminum, explosion-proof; NEMA 4, 5, 7, 9, 12

Housing (Remote Amplifier)

Glass-reinforced polyester; NEMA 4X

Hazardous Area Approvals

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

Probe Options

Teflon®, Kynar®, or stainless-steel rigid and flexible probes up to 250 ft

Accessories

Delevan AFI-150 analog indicator and DFI-150 digital field indicator

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 Cap Analog 420 ideal for remote or hard-to-access tanks?

−

Its remote-mounted electronics can be installed up to 800 feet from the probe, allowing safe and convenient calibration at ground level.

What is the benefit of the remote-mounted electronics design?

The main benefit is safety and serviceability. In applications where the tank top is high, difficult to access, or in a highly hazardous area, the primary electronics enclosure can be mounted safely at grade level or on an accessible platform. This allows all calibration and troubleshooting to be performed easily without climbing the tank.

Can it handle sticky or viscous materials?

Yes. The built-in coating rejection circuit compensates for buildup and maintains accurate readings even in challenging media.

Does the Cap Analog 420 provide both continuous measurement and alarm outputs?

It does. The transmitter delivers a 4–20 mA or 0–10 V analog output plus two independent SPDT relay outputs for alarms or control.

Is the transmitter suitable for hazardous environments?

Absolutely. The preamp housing is explosion-proof (NEMA 7/9) and certified for Class I & II hazardous locations.

How is the transmitter powered?

It operates on 115 or 230 VAC, or 24 VDC, allowing compatibility with various plant power systems.

How does it maintain signal stability over an 800 ft cable run?

The device uses a two-piece design. A small, rugged preamplifier is installed right on the probe and tank, which conditions the low-level capacitance signal. This signal is then transmitted over the long, shielded cable to the remote, powerful amplifier unit, ensuring reliable, noise-free data over the 800 ft distance.

What are the typical applications for this transmitter?

It’s commonly used in chemical storage tanks, wastewater sumps, silos, and process vessels where reliable level control and alarm functions are needed.