Almost all electric load cell types that are on the market work by measuring the deformation of an elastic element as load increases. It is the method of measuring the deformation that varies between load cell types.
Strain Gauge Load Cell: In a Strain Gauge beam cell, there is an insulated resistance foil (strain gauge) that is bonded directly to the beam itself. An excitation voltage is applied to the strain gauge. As load increases, the beam is deformed by bending slightly, and the foil that is bonded to it is also forced to change shape. The change in shape also changes the electrical resistance across the foil, which can be interpreted by the system to give a weight reading. In this style of cell, the sensing element is exposed to the same physical forces to which the beam is exposed.
Eilersen Capacitive Load Cell: Pioneered by the Eilersen company in the 1970’s, the digital capacitive load cell utilizes a ceramic sensor that is placed at a small distance from the elastic beam which is able to measure the deformation without any contact with the beam. In effect, the sensor measures the distance change within the cell as the elastic element moves. Because the sensor is non-contacting, it is not exposed to the forces to which the elastic element is exposed.
The Eilersen Capacitive Weighing system offers significant benefits:
Extremely robust and capable of handling significant shock, overload and sideload. Because the weighing element does not contact the elastic element, it is not subject to overload or sideload forces. No external guide rods, stay-rods, or mounting kits are required to protect the weighing element which is commonly required with strain-gauge systems.
Extremely Hygenic design. Eilersen load cells are designed to minimize potential entrapment areas and to maximize ease of cleaning. All hygienic cells including the CL, DLC, BL, and HBL series are electropolished prior to shipment.
Protected from Welding Voltages. The ceramic weighing element is electrically isolated from the load cell body. The load cells do not need to be removed if welding is required; only the electronics (display and weighing module) must be disconnected and electrically isolated.
A Fully Digital Signal is created within the cell itself. This enables Eilersen to use common coaxial cable to transmit the weighing signal, and because the signal is digital, cable length does not affect accuracy. Cables can be changed in the field without requiring recalibration, and wires can be cut to any length for a clean installation. In addition, the digital signal is much stronger and more stable than an analog signal from a strain gauge and is less prone to electrical interference from nearby motors or drives.’
Dynamic Weighing capability. The Eilersen load cell sends a signal up to 1000 times per second. In addition, full travel for the load cell is less than 0.2mm. This results in a high frequency of resonance, which when coupled with onboard filters and tuning means the Eilersen system offers an extremely fast response for high-speed weighing.
Eilersen System Diagnostics. The digital signal created in the load cell allows an operator to see the performance of each individual cell. This can be highly beneficial during initial installation to ensure that weight is distributed as evenly as possible. If communication is lost with a cell due to a cut wire or poor electrical connection, the system will also provide error codes to show the user which cell requires attention. This diagnostic feature is not available in most strain gauge systems.
Shipping/ Setup cost savings for OEM’s. Eilersen load cells can be factory-installed and shipped to the jobsite without needing to be removed. For most installations, no lockout or shipping blocks are required as the robust load cells can handle any forces encountered during shipment without external protection. This results in significant savings during shipping preparation and site setup.
Extremely High Quality- All Eilersen cells are developed, manufactured and calibrated in-house in their ISO 9001:2015 certified facilities in Switzerland and Denmark.