German POFI ENGINEERING sensors, POFI ENGINEERING models, POFI ENGINEERING prices

POFI ENGINEERING pressure sensors for liquid level measurement. The hydrostatic submersible level transmitter (level gauge) is based on the principle that the static pressure of the measured liquid is proportional to its height. It uses advanced foreign isolated diffused silicon sensitive elements or ceramic capacitive pressure sensitive sensors to convert static pressure into electrical signals, which are then converted into standard electrical signals (typically 4–20mA/15VDC) after temperature compensation and linear correction.

POFI ENGINEERING sensor structure

It consists of two parts: the scale grating and the grating readhead. The figure on the right shows the structure of the grating ruler. The key part of the grating detection device is the grating readhead, which is composed of a light source, condensing lens, index grating, photoelectric elements, and adjustment mechanisms. There are many structural forms of grating readheads, which are classified into direct-receiving readheads (also known as silicon photovoltaic cell readheads), mirror-image readheads, beam-splitter readheads, and metal grating reflective readheads based on their structural characteristics and application scenarios.

POFI ENGINEERING sensor principle

The essence of a grating displacement sensor is to measure position using the grating pitch as a standard scale. High-resolution grating rulers are generally expensive and difficult to manufacture. To improve system resolution, Moiré fringes need to be subdivided; grating ruler sensor systems mostly use electronic subdivision methods. When two gratings overlap at a slight angle, Moiré fringes are generated in a direction roughly perpendicular to the grating lines. As the grating moves, the Moiré fringes move up and down accordingly. This converts the measurement of the grating pitch into the measurement of the number of Moiré fringes. Placing 4 photoelectric devices at certain intervals within one Moiré fringe width enables electronic subdivision and direction determination. For example, for a grating ruler with 50 line pairs/mm, the grating pitch is 0.02mm. With four-fold subdivision, counting pulses with a resolution of 5μm can be obtained, achieving high precision in general industrial measurement and control. Since displacement is a vector, both its magnitude and direction must be detected, requiring at least two photoelectric signals with different phases. To eliminate common-mode interference, DC components, and even harmonics, differential amplifiers composed of low-drift operational amplifiers are typically used. The 4 photoelectric signals obtained from 4 photosensitive devices are sent to the input terminals of 2 differential amplifiers. The two signals output from the differential amplifiers have a phase difference of π/2. To obtain direction determination and counting pulses, these two signals must first be shaped into square waves with a duty cycle of 1:1. Then, by comparing the phases of the square waves, the movement direction of the grating ruler can be determined. By counting the square wave pulses, the displacement and speed of the grating ruler can be obtained.

POFI ENGINEERING sensor usage precautions

Power must be switched off before plugging or unplugging the connector between the linear encoder sensor and the digital readout unit. Install an external protective cover whenever possible, and promptly remove chips and oil splashed onto the scale to strictly prevent any foreign matter from entering the linear encoder sensor housing. Regularly check whether all mounting and connection screws are loose. To extend the service life of the dust-proof sealing strip, apply a thin, even layer of silicone oil to the strip, taking care not to let it splash onto the glass grating etched surface. To ensure reliable operation of the linear encoder sensor, periodically clean and wipe the glass scale surface and the index grating surface with an ethanol mixture (50%) to keep the glass scale surface clean. The linear encoder sensor is strictly prohibited from being subjected to severe vibration or impact, as this may damage the scale; if the scale fractures, the linear encoder sensor will fail. Do not disassemble the linear encoder sensor yourself, and never arbitrarily change the relative gap between the main scale and the secondary scale. Doing so may compromise the accuracy of the linear encoder sensor and cause relative friction between the main and secondary scales, damaging the chrome layer and thus the grating lines, which renders the scale unusable. Take care to prevent oil and water contamination of the scale surface, as this can disrupt the grating line pattern and cause measurement errors. Avoid operating the linear encoder sensor in environments with severe corrosive effects, to prevent corrosion of the chrome layer and the scale surface, which would degrade the quality of the scale.

Weidou Intelligent Technology specializes in selling German POFI ENGINEERING sensors, POFI ENGINEERING proximity sensors, POFI ENGINEERING distance sensors, POFI ENGINEERING vision sensors, POFI ENGINEERING displacement sensors, POFI ENGINEERING load cells, POFI ENGINEERING speed sensors, POFI ENGINEERING photoelectric sensors, POFI ENGINEERING position sensors, POFI ENGINEERING angle sensors, POFI ENGINEERING tactile sensors, POFI ENGINEERING temperature sensors, POFI ENGINEERING pressure sensors, POFI ENGINEERING flow sensors, POFI ENGINEERING level sensors, POFI ENGINEERING motion sensors, and POFI ENGINEERING process sensors. Original imports from Germany. Welcome inquiries and orders.