JP3968767B2 - Vortex flow meter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vortex flow meter, and in particular, in a vortex flow meter converter, performs data transmission between two circuits insulated by an insulating transformer, and controls various gain control or switch on / off. The present invention relates to a vortex flowmeter that can perform the above.
[0002]
[Prior art]
In the vortex flowmeter in the prior art, there are a case where the power source portion and the calculation control unit are insulated, and a case where the sensor unit and the calculation control unit are insulated.
[0003]
As shown in FIG. 4, the vortex flowmeter in which the power supply portion and the arithmetic control unit are insulated has a sensor 300 formed of a piezoelectric element that detects an alternating signal of Karman vortex and a signal detected by the sensor 300. Amplifying circuit 310 for amplifying, A / D converter for converting the amplified signal into a digital value, a filter, and a Schmitt trigger circuit, and a vortex flow rate signal from signal capturing and converting section 320 are signaled. An arithmetic control unit 330 composed of a microprocessor to be processed, a power output circuit 350 that supplies power via an electrically isolated insulating circuit 340, and a resolution that the arithmetic control unit 330 needs for gain control with respect to the amplifier circuit 310 And a control line 360 for outputting a control signal having the number of bits to obtain
[0004]
In the vortex flowmeter having such a configuration, when the gain control of the amplification circuit 310 that amplifies the signal from the sensor 300 is performed, the control line 360 is used to control the number of bits to obtain the resolution necessary for gain control. Then, the status of “H” and “L” is output from the port of the arithmetic control unit 330.
[0005]
Further, the vortex flowmeter in which the amplifier circuit for amplifying the signal from the sensor and the arithmetic control unit are insulated is a sensor formed by a piezoelectric element for detecting an alternating signal of Karman vortex as shown in FIG. 300, an amplification circuit 310 that amplifies the signal detected by the sensor 300, a signal acquisition conversion unit 320 that includes an A / D converter, a filter, and a Schmitt trigger circuit that converts the amplified signal into a digital value, and a signal acquisition A calculation control unit 330 comprising a microprocessor for signal processing of the vortex flow rate signal from the internal conversion unit 320, a power output circuit 350 serving as a power source for the calculation control unit 330, and the calculation control unit 330 for gain control over the amplifier circuit. And a control line 360 for outputting a control signal having the number of bits for obtaining the necessary resolution. The control lines 360 between the amplifier circuit 310 and the signal capture conversion unit 320 and between the arithmetic control unit 330 and the amplifier circuit 310 are provided with insulating circuits 340A and 340B that are electrically insulated. .
[0006]
In the vortex flowmeter having such a configuration, when the amplification circuit 310 and the calculation control unit 330 are insulated by the insulation circuits 340A and 340B, the calculation control unit is used when performing gain control or the like of the amplification circuit 310. Feedback control is performed using one isolation circuit 340A per control line from the port 330.
[0007]
[Problems to be solved by the invention]
However, in the above-described prior art vortex flowmeter, in order to prevent noise, the gain and switch are controlled by the port output of the arithmetic control unit with an insulating circuit configuration having an insulating transformer between the amplifier circuit and the arithmetic control unit. If this is done, the same number of control circuits as the number of control signals is required, which increases the mounting area and costs.
[0008]
Therefore, when insulation is required between the arithmetic control unit that controls the feedback control and the amplifier circuit that amplifies the signal from the sensor that detects the signal, the control line is controlled with a monotonic insulation circuit. It has a problem that must be solved in making it possible.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, the vortex flowmeter according to the present invention is configured as follows.
[0011]
(1) comprising sensor means for generating an alternating signal generated by Karman vortex, an amplifying means for amplifying the alternating signal, and an arithmetic control means for controlling the amplified signal to generate a vortex flow rate signal, The arithmetic control means transmits a feedback signal to and from the amplifying means by a serial data stream method, and an eddy flow meter is provided that is electrically insulated during the transmission.
(2) The vortex flowmeter according to (1), wherein the serial data stream method is UART.
[0012]
In this way, the signal between the amplification part that converts the Karman vortex into an alternating signal and amplifies it and the operation control part that performs feedback control of this amplification part is converted to a serial data stream system, that is, UART and an insulation circuit is provided. With this configuration, even if the number of feedback controls increases, the physical number does not increase and the control method does not become complicated.
[0013]
Hereinafter, embodiments of a vortex flowmeter according to the present invention will be described with reference to the drawings.
[0014]
As shown in FIG. 1, a vortex flowmeter according to the present invention amplifies an alternating signal from a sensor 100 which is a piezoelectric element installed in a vortex generator in order to detect stress due to Karman vortex. An amplifying circuit 110, a signal capturing / converting unit 130 that converts the signal generated by the amplifying circuit 110 into a digital value, and a coil that is electrically insulated between the amplifying circuit 110 and the signal capturing / converting unit 130 A first insulation circuit 120 comprising: a first calculation control unit 180 for calculating and controlling the eddy pulse signal acquired by the signal acquisition conversion unit 130; and a power supply output for supplying power to the first calculation control unit 180 UART (Universal Asynchronous Receiver Trans) which is a serial data stream system from the circuit 190 and the first arithmetic control unit 180. a transmission circuit 170 that transmits data by a transmitter, a reception circuit 150 that receives a signal from the transmission circuit 170, a second insulation circuit 160 that is electrically insulated between the transmission circuit 170 and the reception circuit 150, and reception The second arithmetic control unit 140 is a so-called small pin microcomputer that performs arithmetic control for feedback control of the amplifier circuit 110 based on the signal received by the circuit 150. The second arithmetic control unit 140 and the amplifier circuit 110 Are connected by a control line 200. The second calculation control unit 140 receives communication from the first calculation control unit 180 and generates an output signal at the port according to the communication content. UART is asynchronous communication, and converts data coming from a parallel bus such as a microprocessor into a serial bit stream.
[0015]
In the vortex flowmeter having such a configuration, when the first arithmetic control unit 180 communicates a serial data stream method (UART) feedback signal to the second arithmetic control unit 140, the received second arithmetic control unit The unit 140 interprets the content of the received communication. Based on the interpreted contents, the second arithmetic control unit 140 formed of a small pin microcomputer sets the port to “H” or “L” and sends a signal to the control line 200 to perform feedback control of the amplifier circuit 110. Do.
[0016]
Thus, since information is sent by UART (asynchronous communication), a plurality of information can be sent by one line. Therefore, only one insulating circuit and communication circuit are required, which is effective in terms of cost and mounting area. Further, since the second arithmetic control unit 140, which is a small pin microcomputer on the receiving side, interprets the communication contents by a program, the change of the communication contents can be made very flexible without requiring complicated hardware. Since the second arithmetic control unit 140, which is a small pin microcomputer, uses a general-purpose one, if a small pin microcomputer of the optimum size is selected from the number of ports required for setting, it is necessary for low cost and space saving. You can control.
[0017]
FIG. 2 shows a vortex flowmeter of application 1, which enables two-way communication between the first calculation control unit 180 and the second calculation control unit 140. That is, a transmission circuit 170A for transmission is provided on the first calculation control unit 180 side of the second insulation circuit 160 provided between the first calculation control unit 180 and the second calculation control unit 140, and A reception circuit 150B is provided, and a reception circuit 150A for reception and a transmission circuit 170B for transmission are provided on the second arithmetic control unit 140 side.
[0018]
With such a configuration, in communication from the first arithmetic control unit 180, a signal is transmitted to the second arithmetic control unit 140 via the transmission circuit 170A, the second insulation circuit 160, and the reception circuit 150A. Can do. On the other hand, when the first calculation control unit 180 receives a signal from the second calculation control unit 140, communication can be performed via the transmission circuit 170B, the second insulation circuit 160, and the reception circuit 150B.
[0019]
In this way, when compared with the one-way communication described with reference to FIG. 1, the transmission information from the first calculation control unit 180 is processed normally on the second calculation control unit 140 side, compared to the one-way communication described with reference to FIG. It becomes possible to know whether the first arithmetic control unit 180 on the main controller side. In other words, by enabling bidirectional communication, a response to communication can be returned, and the first control operation unit 180 on the transmission side can confirm the processing, thereby increasing reliability and the like. It becomes possible.
[0020]
FIG. 3 shows the vortex flowmeter of application 2, which is configured to enable bidirectional communication and each configured to use a separate system of insulation circuit.
[0021]
The configuration is such that, between the first control calculation unit 180 and the second control calculation unit 140, the transmission circuit 170A and the reception in the direction of transmission from the first calculation control unit 180 to the second calculation control unit 140 side. A third insulation circuit 160A is provided between the circuits 150A, and a fourth insulation is provided between the transmission circuit 170B and the reception circuit 150B in the direction of transmission from the second computation control unit 140 to the first computation control unit 180 side. The circuit 160B is provided. Other configurations are the same as those shown in FIG.
[0022]
With such a configuration, a response to the transmission signal from the first arithmetic control unit 180 can be returned in the same way as in the bidirectional communication, that is, the vortex flowmeter in the application 1, and the processing can be performed. Confirmation can be performed on the first arithmetic control unit 180 side, and reliability and the like can be increased, and separate insulation circuits (third and fourth insulations) are used for signal lines in the transmission direction and reception direction. By providing the circuits 160A and 160B), the insulation circuit itself increases, but the influence of interference and the like caused by sharing transmission and reception can be eliminated.
[0023]
【The invention's effect】
As described above, the vortex flowmeter of the present invention needs to use the same number of insulation circuits as the control lines because the signal for feedback control to the amplifier circuit is transmitted and received by a serial data stream method, for example, UART. This eliminates the increase in control lines and insulation circuits, prevents an increase in mounting area and cost, and allows control signals to be freely controlled with only UART software improvements. There is an effect that a vortex flow meter can be realized.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a circuit configuration of a vortex flowmeter adopting a serial data stream method according to the present invention.
FIG. 2 is a block diagram of a circuit configuration which is a vortex flowmeter of the first application example and realizes bidirectional communication capable of receiving a transmission signal and a reception signal in a serial data stream method.
FIG. 3 is a block diagram of a circuit configuration that realizes bidirectional communication in which an insulation circuit is provided for each of a transmission signal and a reception signal in a serial data stream method, which is a vortex flowmeter of the second application example. .
FIG. 4 is a block diagram of a circuit configuration in which a power supply portion and an arithmetic control unit are electrically insulated in a vortex flowmeter according to the prior art.
FIG. 5 is a block diagram of a circuit configuration in which the amplifying part and the arithmetic control unit are electrically insulated in the vortex flowmeter according to the prior art.
[Explanation of symbols]
100 Sensor 110 Amplifier circuit 120 Insulating circuit 130 Signal acquisition conversion unit 140 Second arithmetic control unit 150 Reception circuit 150A Reception circuit 150B Reception circuit 160 Second insulation circuit 160A Third insulation circuit 160B Fourth insulation circuit 170 Transmission Circuit 170A Transmission circuit 170B Transmission circuit 180 First arithmetic control unit 190 Power supply output circuit 200 Control line

Claims (2)

Sensor means for generating an alternating signal generated by Karman vortex, an amplifying means for amplifying the alternating signal, and an arithmetic control means for calculating and controlling the amplified signal to generate a vortex flow rate signal,
The arithmetic control means transmits a feedback signal to and from the amplifying means in a serial data stream system, and an eddy flow meter provided with an insulating circuit that is electrically insulated during the transmission. . The vortex flowmeter according to claim 1, wherein the serial data stream method is UART.

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