Design method for processing circuit of photoelectric liquid-level instrument

Abstract

The invention discloses a design method for a processing circuit of a photoelectric liquid-level instrument. According to the design method, a power supply for supplying power, an adjustable power supply, an infrared light-emitting diode array, a light-emitting tube control unit, an infrared receiving tube array, a multi-channel analog switch, an A/D (Analog/Digital) converter and a processor are included. The design method is characterized in that the processor is respectively conducted with the light-emitting tube control unit, the multi-channel analog switch and the adjustable power supply; the processor is conducted with the output end of the multi-channel analog switch through the A/D converter; the output end of the light-emitting tube control unit is respectively conducted with each branch at the input end of the infrared light-emitting diode array; the infrared light-emitting diode array is connected with the adjustable power supply; and the input end of the multi-channel analog switch is respectively conducted with each branch at the output end of the infrared receiving tube array. The processing circuit is low in power consumption, wide in power supply range and ultrastrong in error correcting capability for sensor data; and the work performance of the instrument is improved; and the reliability of the instrument is enhanced.

Description

Technical field [0001] The invention belongs to the technical field of liquid level measurement, and is a design method of a processing circuit of a photoelectric liquid level instrument. Background technique [0002] The steel belt level gauge has been widely used in the measurement of oil storage tanks, and the infrared photoelectric sensor method is the most used in the steel belt level gauge. Infrared photoelectric sensor is generally composed of a group of infrared light-emitting tubes, a group of infrared receiving tubes, and a transparent stainless steel Gray code belt or Gray code plate sandwiched between the light-emitting tube and the receiving tube and linked with the liquid level. The position of the light-emitting tube and the receiving tube One to one correspondence. The usual implementation method connects all the light-emitting tubes in series and then drives them to emit light by a constant current source. After the receiving tube passes the pull-up or pull-down...

AI Technical Summary

Problems solved by technology

This method has the following problems: First, it is difficult to select a safety barrier

Since the logic level identification requirements of the gate circuit or the IO of the CPU must be 0.7Vcc, and the logic judgment at the (0.3~0.7) Vcc voltage input terminal is uncertain, this requires infrared light emitting and receiving logic The matching is very strict, otherwise the data of the level gauge will jump

The third is the large amount of maintenance and long-term performance reduction

The long-term work of the instrument on site reduces the performance of the light-emitting receiving tube, and the stains on the light-transmitting code tape and the influence of the operating position deviation will cause the logic level to be unsatisfactory and cause data errors, which will affect the instrument’s work and detection, and increase on-site maintenance. Work intensity of personnel

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