RF level switches from ASI Instruments immune to build-up

ShieldPoint Series RF (radio frequency) capacitance switches from ASI Instruments are built for point level detection in a variety of applications, from sticky slurries to low dielectric bulk solids.

By Control Engineering Staff May 19, 2005
ShieldPoint Series RF (radio frequency) capacitance switches from ASI Instruments have no moving parts .

ShieldPoint Series RF (radio frequency) capacitance switches from ASI Instruments are built for point level detection in a variety of applications, from sticky slurries to low dielectric bulk solids. Rugged design has no moving parts and features LED operation and calibration lights visible through the standard window cover. Modular electronics use the company’s patented Ashield technology, which provides immunity to material built-up.

ShieldPoint 300 is a single-point level switch featuring 3-element shielded probes and a 10 A DPDT (double-pole, double-throw) relay. ShieldPoint 400 is a multi-point switch with a variety of probe options, including a 3-element probe, Teflon coated or bare rods and cables, and 2 SPDT (single-pole, double-throw) 10 A relays. The 400 offers a choice of operating modes: single setpoint, dual setpoint, and pump control. Dual setpoint function lets the unit replace two single-point switches.

Simple, one-step calibration process uses an external magnet. Adjustments, such as calibration, sensitivity, and time delay, can be made while maintaining the explosion-proof integrity of the switch. An “out-of-calibration” warning lets the user know when build-up is present on the probe and recalibration may be needed. A variety of probes is available for specialized options. They include the standard probe for multi-purpose applications; stub or bent probes for small hoppers and vessels; flexible or rigid tip extensions for increased range; and cable probes for ranges up to 150 ft (45 m).

—Jeanine Katzel, senior editor, Control Engineering, jkatzel@reedbusiness.com