Monitor TrueCap RF Capacitance Sensor

TrueCap® RF capacitance sensors offer cost-effective point level monitoring with reliability you can count on. Monitor’s complete line, which features models MK-2 and MK-2e, provides you with the most affordable solution for your application. Monitor’s RF capacitance probes are designed to provide a high level of sensitivity, stability and durability for powder and bulk solids applications, as well as liquid and slurry applications. Monitor’s two-year warranty stands behind every TrueCap sensor.

Principle of Operation:
A radio frequency is applied to the probe and is continually analyzed to determine the influence caused by the surrounding environment. As material contacts the probe, the radio frequency shifts indicating an increase in capacitance (C). The active probe of the unit and the vessel’s wall make up the two plates (A=area) of a capacitor which are separated by a fixed distance (d). The probe’s insulator and surrounding air provide the dielectric material (with dielectric constant “K”). As the air (K=1.0) is displaced with any other material (K > 1.0), the capacitance effect (C) is enhanced, thereby changing the application’s impedance. This influence is measured within the circuitry and compared to a reference established by the sensitivity setting. The setting determines how much influence must be present before the output changes.

The driven shield section of the probe enables the circuitry to ignore product build-up on the probe that would otherwise cause false sensing. The driven shield is activated with the same radio frequency potential as the sensing probe. Since current can not flow between identical potentials, the driven shield blocks current flow from the active probe to the vessel wall through the material build-up, thereby eliminating the sensing of the material build-up.

Applications:
TrueCap® RF capacitance point level sensors are versatile devices providing high and low level readings in bins, silos, tanks, hoppers, and other vessels. TrueCap’s superior sensitivity range allows users to properly adjust units to meet the needs of a wide variety of applications. Whether your application is for a powder, liquid, granular solid, or viscous material, the TrueCap product line offers the right solution.

Mk-2:
The TrueCap® Model MK-2 RF capacitance point level sensor is a proven problem solver used to ensure maximum performance and reliability, minimizing downtime of operations.

Features:
Microcontroller based for maximum reliability & performance
Push-button calibration, sensitivity selection & self-test
Automatic temperature compensation for unmatched calibration stability
Superior 0.5 pF sensitivity ensures reliability
Build-up immunity helps eliminate false signals
High intensity LED indicating light (Ordinary location sensors only)
Universal power supply minimizes versions
Available hazardous locations approval with intrinsic safety

Mk-2e:
The TrueCap® Model MK-2e RF capacitance point level sensor is a reliable sensor and is a standard for many OEMs and end users requiring versatility and lower cost.

Features:
Superior 0.5 pF sensitivity ensures reliability.
Build-up immunity helps eliminate false signals.
High intensity LED indicating light (Ordinary location integral sensors only).
Available hazardous locations approval with intrinsic safety.
Simple 2-step manual calibration.
Economical.

Split Architecture:
For applications involving high temperature or vibration, the probe and electronics are housed in separate enclosures mounted 12 feet (3.6 m) apart or more depending on the application, thereby removing the electronics from the stressful conditions. All adjustments are performed at the remote electronics.

Cable Extension Probe:
The cable extension probe can extend the sensing point up to 50 feet (15 m) beneath the mounting point. It should be noted that the build-up immunity, however, is not extended with the cable version. Use the pipe extension probe in those applications requiring build-up immunity. A 1-1/4” NPT, 1-1/2” BSPT* or 3/4” NPT process connection is available.
*Unit with 1-1/2” BSPT connection is provided with M20 cable glands.

Food Grade Probe:
Most probe variations are available with nylon insulators for food grade applications. Food grade probes are usually outfitted with the stainless steel connection.