CN205593605U - Liquid level changer based on CAN bus - Google Patents

Abstract

The utility model discloses a liquid level changer based on CAN bus, include probe, synchronous circuit, high voltage dc source circuit, ultrasonic emission circuit, amplitude limiting protection circuit, high -frequency amplifier circuit, filter circuit, AD converting circuit, translate code spraying control, acquisition controller, optoelectronic isolation ware and bus transceiver, the utility model discloses an ultrasonic testing technique, can be independent of with by outside the tracer liquid, liquid kind no matter, the container kind can all accurate detection liquid level position, on the other hand, the utility model discloses a field bus technique (CAN bus) has realized on -the -spot instrument and multiple spot, intelligence, bidirectional network between control system and the control room and has been connected, lays a good foundation for intelligent mill.

Description

Fluid level transmitter based on CAN

Technical field

This utility model relates to a kind of fluid level transmitter, a kind of fluid level transmitter based on CAN, belongs to liquid depth and measures apparatus field.

Background technology

Fluid level transmitter liquid is the detection of the height of liquid level in closed or open container in the industrial processes.The utilization of fluid level transmitter very extensive, it is the extension to pressure transmitter technology and development, liquid according to different specific weight is in the linear principle of the produced pressure of differing heights, it is achieved accurately the measuring and transmit of, weight high to volume, the liquid of water, oil and pastel.Knowable to its measuring principle, fluid level transmitter is all by carrying out work by measuring pressure in himself input liquid, and shortcoming is that scope liquid body temperature, the corrosive nature air-proof condition etc. measured limit, and to be also carried out fluid level transmitter after using a period of time.

Summary of the invention

This utility model purpose is to provide a kind of fluid level transmitter based on CAN, and this fluid level transmitter can measure the liquid level of various liquid.

To achieve these goals; a kind of fluid level transmitter based on CAN of this utility model, including probe, synchronous circuit, high voltage direct current source circuit, ultrasonic emitting circuit, limiter protection circuit, high-frequency amplifier circuit, filter circuit, A/D change-over circuit, decoding control circuit, acquisition controller, photoisolator and bus transceiver；Synchronous circuit produces lock-out pulse and gives ultrasonic emitting circuit and A/D change-over circuit respectively；High voltage direct current source circuit provides high pressure activation power supply for ultrasonic emitting circuit；The pulse signal that ultrasonic emitting circuit is formed sends through probe；Echo-signal enters limiter protection circuit after probe receives, then enters A/D change-over circuit through high-frequency amplifier circuit and filter circuit；A/D change-over circuit carries out data conversion under the synchronization of lock-out pulse；Acquisition controller controls high-frequency amplifier circuit and A/D change-over circuit by decoding control circuit；The result data of collection is mail to CAN through photoisolator and bus transceiver by acquisition controller.

This utility model uses ultrasonic detecting technology, can independent of with detected liquid outside, no matter class of liquids, container types, can accurately detect liquid level position；On the other hand, this utility model uses field bus technique (CAN), it is achieved that the multiple spot between field instrument with control system and control room, intelligence, bilateral network are connected, and lays a good foundation for intelligent factory.

Accompanying drawing explanation

Fig. 1 is this utility model theory diagram；

Fig. 2 is this utility model ultrasound emission circuit composition frame chart.

Detailed description of the invention

Below in conjunction with the accompanying drawings this utility model is described further.

As shown in Figure 1; a kind of fluid level transmitter based on CAN, including probe, synchronous circuit, high voltage direct current source circuit, ultrasonic emitting circuit, limiter protection circuit, high-frequency amplifier circuit, filter circuit, A/D change-over circuit, decoding control circuit, acquisition controller, photoisolator and bus transceiver；Synchronous circuit produces lock-out pulse and gives ultrasonic emitting circuit and A/D change-over circuit respectively；High voltage direct current source circuit provides high pressure activation power supply for ultrasonic emitting circuit；The pulse signal that ultrasonic emitting circuit is formed sends through probe；Echo-signal enters limiter protection circuit after probe receives, then enters A/D change-over circuit through high-frequency amplifier circuit and filter circuit；A/D change-over circuit carries out data conversion under the synchronization of lock-out pulse；Acquisition controller controls high-frequency amplifier circuit and A/D change-over circuit by decoding control circuit；The result data of collection is mail to CAN through photoisolator and bus transceiver by acquisition controller.

What radiating circuit was the most frequently used has resonant mode and disresonance type two class, and wherein the tranmitting frequency of resonant mode radiating circuit is determined by the resonant frequency of circuit, and the tranmitting frequency of disresonance type radiating circuit is determined by the natural frequency that pop one's head in (piezoquartz) is own.As shown in Figure 2, native system uses disresonance type radiating circuit, including internal trigger circuit, triggering selection circuit, high-voltage control circuit, circuit for producing high voltage, pulse width control circuit, impulse output circuit and pulse generator, internal trigger circuit produces triggering pulse and is triggered selection circuit entrance pulse generator, high-voltage control circuit controls circuit for producing high voltage and gives pulse generator high voltage power supply, pulse generator, under triggering the effect of pulse and pulse width control circuit, is formed after high pressure launches pulse and exports through impulse output circuit.

Described probe is double crystal probe.Double crystal probe is launched wafer T also known as associating dual probe or partition type TR(, is received wafer R) probe.This probe contains two piezoelectric chips, is contained in same housing, and a wafer is launched, another wafer receipt.Further, launch and receive wafer can be prepared with the piezoelectric (such as lithium sulfate) that the high piezoelectric (such as lead zirconate titanate) of transmitting sensitivity and receiving sensitivity are high respectively.Therefore, transmitting and the receiving sensitivity of this probe are the highest, and single crystal probe cannot accomplish this point.It addition, separate with sound absorption properties strong, the sound insulating layer of good insulating between two wafers of double crystal probe, initial spike can not enter reception amplifier, overcomes choking phenomenon, the most effectively prevents the interface clutter launched between pulse and delay block to enter and receives wafer.And with lucite delay block before wafer, make acoustical impedance a period of time enter workpiece.Owing to launching and receiving separately, and employ delay block, so substantially reducing blind area, the beneficially detection of near surface flaw.

Claims (3)

1. a fluid level transmitter based on CAN; it is characterized in that, including probe, synchronous circuit, high voltage direct current source circuit, ultrasonic emitting circuit, limiter protection circuit, high-frequency amplifier circuit, filter circuit, A/D change-over circuit, decoding control circuit, acquisition controller, photoisolator and bus transceiver；Synchronous circuit produces lock-out pulse and gives ultrasonic emitting circuit and A/D change-over circuit respectively；High voltage direct current source circuit provides high pressure activation power supply for ultrasonic emitting circuit；The pulse signal that ultrasonic emitting circuit is formed sends through probe；Echo-signal enters limiter protection circuit after probe receives, then enters A/D change-over circuit through high-frequency amplifier circuit and filter circuit；A/D change-over circuit carries out data conversion under the synchronization of lock-out pulse；Acquisition controller controls high-frequency amplifier circuit and A/D change-over circuit by decoding control circuit；The result data of collection is mail to CAN through photoisolator and bus transceiver by acquisition controller.

Fluid level transmitter based on CAN the most according to claim 1, it is characterized in that, described ultrasonic emitting circuit uses disresonance type radiating circuit, including internal trigger circuit, triggering selection circuit, high-voltage control circuit, circuit for producing high voltage, pulse width control circuit, impulse output circuit and pulse generator, internal trigger circuit produces triggering pulse and is triggered selection circuit entrance pulse generator, high-voltage control circuit controls circuit for producing high voltage and gives pulse generator high voltage power supply, pulse generator is under triggering the effect of pulse and pulse width control circuit, formed after high pressure launches pulse and export through impulse output circuit.

Fluid level transmitter based on CAN the most according to claim 1 and 2, it is characterised in that described probe is double crystal probe.