Device and method for synthesizing start-up signal of Coriolis flowmeter with full digital waveform

A Coriolis flowmeter and waveform synthesis technology, applied to mass flow measurement devices, measurement devices, direct mass flow meters, etc., can solve problems such as inability to adapt to the environment, cumbersome control process, complex design, etc., and achieve stable vibration effects Reliable, good robustness, and the effect of increasing the vibration speed

CN105784037BInactive Publication Date: 2018-11-13NORTHWESTERN POLYTECHNICAL UNIV
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2018-11-13
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention relates to a device and a method for synthesizing Coriolis flowmeter vibration starting signals through all-digital waveforms. The device comprises a microcontroller, a direct digital frequency synthesizer (DDS), a multiplication digital-analog converter (MDAC) and an audio power amplifier. After the device is powered on, the DDS is controlled by the microcontroller to constantly synthesize and output 1-Hz square wave signals, at the same time, the microcontroller writes control words into the MDAC, the square wave signals passing the MDAC are subjected to amplitude modulation and amplification according to size of the control words and amplified by a fixed multiple through work, and final amplitude of the square wave signals is adjusted to 9 Vpp. The signals are input into a flow tube to realize quick vibration starting of the flow tube.
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Description

technical field

[0001] The invention aims at the driving system of the Coriolis mass flowmeter, and designs a 1Hz all-digital driving vibration starting device and method based on harmonic decomposition. Background technique

[0002] Coriolis mass flowmeter (hereinafter referred to as Coriolis flowmeter) is a kind of direct mass flowmeter made by Coriolis principle. It is one of the most rapidly developing flowmeters. It can measure various conventional liquids, and can also be applied to the measurement of unconventional fluids such as slurry, liquefied gas and compressed natural gas, and is widely used in petrochemical, food and pharmaceutical industries.

[0003] The Coriolis flowmeter is mainly composed of a flow tube (also known as a vibrating tube), a sensor, a signal processing system, and a drive system (also known as an excitation system). Among them, the performance of the drive system directly affects the overall measurement accuracy of the flowmeter. The tradit...

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Embodiment Construction

[0021] Now in conjunction with embodiment, accompanying drawing, the present invention will be further described:

[0022] Aiming at the all-digital drive system of the Coriolis flowmeter, the present invention proposes a method for synthesizing the start-up signal of the Coriolis flowmeter with a 1Hz all-digital waveform based on harmonic decomposition, and designs and implements a set of all-digital drive devices according to the method. The device includes: a microcontroller, a direct digital frequency synthesizer (hereinafter referred to as DDS), a multiplying digital-to-analog converter (hereinafter referred to as MDAC), and an audio power amplifier (hereinafter referred to as power amplifier). The hardware connection relationship of the device is as follows: figure 1 shown. The data output pin of the microcontroller is connected to the input pin of DDS and MDAC, the output pin of DDS is connected to the input pin of MDAC, the output pin of MDAC is connected to the input...