阅读说明：本技术 一种带可调滞回功能的电接点液位信号采集方法及系统 (Electric contact liquid level signal acquisition method and system with adjustable hysteresis function ) 是由 周静 刘明星 秦官学 梁建 严浩 杨有维 黄起昌 陈智 田旭峰 于 2020-11-26 设计创作，主要内容包括：本发明公开了一种带可调滞回功能的电接点液位信号采集方法及系统,本发明根据液位传感器在液面呈现的电阻特性设置输入滞回区间,且所述输入滞回区间可配置；一路液位采集信号对应一路输出,同时输出状态可配置。本发明可以实时、准确可靠地检测液位的深度,特别是在核电等高要求技术领域,可以对二回路系统的蒸汽发生器、冷却水源等液位进行实时监视,并作出相应的输出操作,达到自动控制保持液位的效果。(The invention discloses an electric contact liquid level signal acquisition method and system with an adjustable hysteresis function, wherein an input hysteresis interval is set according to the resistance characteristic presented by a liquid level sensor on the liquid level, and the input hysteresis interval is configurable; one path of liquid level acquisition signal corresponds to one path of output, and the output state can be configured. The invention can accurately and reliably detect the depth of the liquid level in real time, and particularly can monitor the liquid levels of a steam generator, a cooling water source and the like of a two-loop system in real time and perform corresponding output operation in the technical field with high requirements on nuclear power and the like, thereby achieving the effect of automatically controlling and maintaining the liquid level.)

1. An electric contact liquid level signal acquisition method with an adjustable hysteresis function is characterized in that an input hysteresis interval is set according to resistance characteristics presented by a liquid level sensor on a liquid level, and the input hysteresis interval is configurable;

one path of liquid level acquisition signal corresponds to one path of output, and the output state can be configured.

2. An electrical contact level signal collection method with adjustable hysteresis as defined in claim 1 wherein the level sensor is powered by an ac power source that converts a dc power signal to an ac power signal.

3. An electrical contact level signal collection method with adjustable hysteresis as claimed in claim 1 wherein the method configures the resistance of the collection resistor in series with the level sensor to obtain at least one input hysteresis band.

4. An electric contact liquid level signal acquisition method with an adjustable hysteresis function as claimed in claim 3, wherein two input hysteresis intervals are configured, specifically comprising:

gears 1, 80k Ω -400 k Ω: the liquid level is lower than or equal to 80k omega, the liquid level is higher than or equal to 400k omega, and the other states are uncertain;

gear 2, 160k Ω to 700k Ω: the liquid level is below 160k omega or above 700k omega, and the other states are uncertain;

the hysteresis threshold voltage of the hysteresis circuit is calculated by the following formula (1) and formula (2):

in the formula, VREF _ COM is a reference voltage generated by a reference source, VTH is a hysteresis threshold high voltage, and VTL defines a hysteresis threshold low voltage.

5. An electrical contact liquid level signal acquisition method with an adjustable hysteresis function as claimed in claim 1, wherein the method performs corresponding contact output actions on the acquired liquid level state, and the state of an output contact is configurable, and the specific configuration comprises:

when the liquid level sensor is under the liquid level, the output of the contact closing or opening is executed;

or the liquid level sensor is above the liquid level, the output of contact closing or opening is performed.

6. An electric contact liquid level signal acquisition system with an adjustable hysteresis function is characterized by comprising an acquisition circuit, an absolute value circuit, a hysteresis circuit and an output circuit;

the acquisition circuit is used for converting differential voltage signals at two ends of an input acquisition resistor into single-ended signals;

the absolute value circuit is used for converting the single-end signal into a positive signal;

the hysteresis circuit sets an input hysteresis interval for a positive signal according to the resistance characteristic presented by the liquid level sensor on the liquid level, so as to prevent the positive signal from shaking back and forth, and the hysteresis interval can be configured;

the output circuit is used for configuring the output state of the signal processed by the hysteresis circuit.

7. An electrical contact liquid level signal acquisition system with adjustable hysteresis of claim 6 further comprising an ac power supply;

and the alternating current power supply is used for converting the direct current power supply signal into an alternating current power supply signal and supplying power to the liquid level sensor.

8. An electrical contact level signal collection system with adjustable hysteresis as claimed in claim 6 wherein the hysteresis loop is designed based on the resistance characteristic presented by the level sensor at the fluid level, and the hysteresis loop is capable of providing at least one input hysteresis loop by configuring the resistance of the collection resistor in series with the level sensor.

9. An electrical contact liquid level signal acquisition system with an adjustable hysteresis function as claimed in claim 8, wherein the hysteresis circuit provides two input hysteresis intervals, specifically comprising:

gears 1, 80k Ω -400 k Ω: the liquid level is lower than or equal to 80k omega, the liquid level is higher than or equal to 400k omega, and the other states are uncertain;

gear 2, 160k Ω to 700k Ω: the liquid level is below 160k omega or above 700k omega, and the other states are uncertain;

the hysteresis threshold voltage of the hysteresis circuit is calculated by the following formula (1) and formula (2):

in the formula, VREF _ COM is a reference voltage generated by a reference source, VTH is a hysteresis threshold high voltage, and VTL defines a hysteresis threshold low voltage.

10. An electrical contact liquid level signal acquisition system with an adjustable hysteresis function as claimed in claim 6, wherein the output circuit performs corresponding contact output actions on the acquired liquid level state, and the state of the output contact is configurable, and the specific configuration comprises:

when the liquid level sensor is under the liquid level, the output of the contact closing or opening is executed;

or the liquid level sensor is above the liquid level, the output of contact closing or opening is performed.

Technical Field

The invention belongs to the technical field of digital instrument control of nuclear power plants, and particularly relates to an electric contact liquid level signal acquisition method and system with an adjustable hysteresis function.

Background

In the field of industrial control, especially in the field of digital instrument control of nuclear power plants, the liquid levels of a steam generator, a cooling water source and the like of a secondary loop system of the nuclear power plant are often monitored and fed back, so that a water level signal is regulated and a liquid level state alarm is given through a control system.

In the existing liquid level detection system, false triggering can be generated when the liquid level signal fluctuates, so that false alarm of the liquid level state can occur; in addition, the characteristics of different electric contact liquid level sensors embodied in different liquid levels are inconsistent, and the existing liquid level detection system does not process the characteristics, so that the reliability and the precision of the acquired liquid level signals are poor.

Disclosure of Invention

The invention provides an electric contact liquid level signal acquisition method with an adjustable hysteresis function, aiming at solving the technical problem of accurately and reliably acquiring an electric contact liquid level signal.

The invention is realized by the following technical scheme:

an electric contact liquid level signal acquisition method with an adjustable hysteresis function is characterized in that an input hysteresis interval is set according to the resistance characteristic presented by a liquid level sensor on the liquid level, and the input hysteresis interval is configurable;

one path of liquid level acquisition signal corresponds to one path of output, and the output state can be configured.

In order to avoid the false alarm of the liquid level signal state, the invention designs the input hysteresis function, and avoids the false triggering generated when the liquid level signal fluctuates; meanwhile, different hysteresis interval gears can be selected through configuration according to the characteristics of the collected signals.

Preferably, the method of the present invention provides power to the level sensor by means of an ac power source for converting a dc power signal into an ac power signal. Because the liquid level sensor supplies power for alternating current, and the liquid level sensor is supplied with power for direct current of a unified interface, the liquid level sensor is supplied with power by an alternating current power supply of converting DC into AC power supply.

Preferably, the method of the present invention can configure at least one input hysteresis interval by configuring the resistance value of the collecting resistor connected in series with the liquid level sensor. In consideration of the fact that different electric contact liquid level sensors reflect different liquid levels with different characteristics, the input hysteresis section is flexibly configured, and the selection can be carried out according to the actual application scene.

Preferably, the method of the present invention is configured to obtain two input hysteresis intervals, specifically including:

gears 1, 80k Ω -400 k Ω: the liquid level is lower than or equal to 80k omega, the liquid level is higher than or equal to 400k omega, and the other states are uncertain;

gear 2, 160k Ω to 700k Ω: the liquid level is below 160k omega or above 700k omega, and the other states are uncertain;

the hysteresis threshold voltage of the hysteresis circuit is calculated by the following formula (1) and formula (2):

in the formula, VREF _ COM is a reference voltage generated by a reference source, VTH is a hysteresis threshold high voltage, and VTL defines a hysteresis threshold low voltage.

Preferably, the method of the present invention performs a corresponding contact output action on the collected liquid level state, and the state of the output contact is configurable, and the specific configuration includes:

when the liquid level sensor is under the liquid level, the output of the contact closing or opening is executed;

or the liquid level sensor is above the liquid level, the output of contact closing or opening is performed.

The output signal of the invention can select the output state according to the characteristics of the post-stage equipment, and the output state can be flexibly configured.

On the other hand, the invention also provides an electric contact liquid level signal acquisition system with an adjustable hysteresis function, which comprises an acquisition circuit, an absolute value circuit, a hysteresis circuit and an output circuit;

the acquisition circuit is used for converting differential voltage signals at two ends of an input acquisition resistor into single-ended signals;

the absolute value circuit is used for converting the single-end signal into a positive signal;

the hysteresis circuit sets an input hysteresis interval for a positive signal according to the resistance characteristic presented by the liquid level sensor on the liquid level, so as to prevent the positive signal from shaking back and forth, and the hysteresis interval can be configured;

the output circuit is used for configuring the output state of the signal processed by the hysteresis circuit.

Preferably, the system of the present invention further comprises an ac power source;

and the alternating current power supply is used for converting the direct current power supply signal into an alternating current power supply signal and supplying power to the liquid level sensor.

Preferably, the hysteresis interval of the present invention is designed according to the resistance characteristic of the liquid level sensor presented on the liquid level, and the hysteresis circuit can provide at least one input hysteresis interval by configuring the resistance value of the collecting resistor connected in series with the liquid level sensor.

Preferably, the hysteresis circuit of the present invention provides two input hysteresis intervals, specifically including:

gears 1, 80k Ω -400 k Ω: the liquid level is lower than or equal to 80k omega, the liquid level is higher than or equal to 400k omega, and the other states are uncertain;

gear 2, 160k Ω to 700k Ω: the liquid level is below 160k omega or above 700k omega, and the other states are uncertain;

the hysteresis threshold voltage of the hysteresis circuit is calculated by the following formula (1) and formula (2):

in the formula, VREF _ COM is a reference voltage generated by a reference source, VTH is a hysteresis threshold high voltage, and VTL defines a hysteresis threshold low voltage.

Preferably, the output circuit of the present invention performs a corresponding contact output action on the collected liquid level state, and the state of the output contact is configurable, and the specific configuration includes:

when the liquid level sensor is under the liquid level, the output of the contact closing or opening is executed;

or the liquid level sensor is above the liquid level, the output of contact closing or opening is performed.

The invention has the following advantages and beneficial effects:

1. the invention can accurately and reliably detect the depth of the liquid level in real time, particularly in the technical field with high requirements on nuclear power and the like, can monitor the liquid levels of a steam generator, a cooling water source and the like of a two-loop system in real time, and performs corresponding output operation, thereby achieving the effect of automatically controlling and maintaining the liquid level. Meanwhile, the output signals can also be sent to a corresponding alarm system.

2. The invention prevents the liquid level from shaking and prevents the sensor characteristic from fluctuating by setting the input hysteresis interval which is flexible and configurable, thereby avoiding false triggering.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:

FIG. 1 is a schematic block diagram of the system of the present invention.

FIG. 2 is a schematic diagram of the AC power supply principle of the liquid level sensor of the present invention.

Figure 3 is a schematic diagram of the LMC555 timer of the present invention.

Fig. 4 is a schematic diagram of an absolute value circuit of the present invention.

Fig. 5 is a schematic diagram of the hysteresis circuit of the present invention.

Fig. 6 is a schematic diagram of the acquisition circuit of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not used as limitations of the present invention.

Example 1

Compared with the existing liquid level signal acquisition technology, the embodiment provides an electric contact liquid level signal acquisition method with an adjustable hysteresis function.

In order to avoid the false alarm of the liquid level signal state, the embodiment designs the input hysteresis function, and avoids the false triggering generated when the liquid level signal fluctuates; meanwhile, different hysteresis interval gears can be selected through configuration according to the characteristics of the collected signals.

The method of the embodiment can configure at least one input hysteresis interval by configuring the resistance value of the acquisition resistor connected in series with the liquid level sensor. In consideration of the fact that different electric contact liquid level sensors reflect different liquid levels with different characteristics, the input hysteresis section is flexibly configured, and the selection can be carried out according to the actual application scene.

The embodiment can be applied to the acquisition of the liquid level state in the safety-level digital instrument control system of a nuclear power plant or other industrial control fields, and corresponding contact output actions are made on the acquired liquid level state, and the state of the output contact can be flexibly configured according to the requirements of the safety state.

Example 2

Based on the method provided by embodiment 1, this embodiment provides an electric contact liquid level signal acquisition system with an adjustable hysteresis function, and as shown in fig. 1, the system of this embodiment includes an ac power supply, an acquisition circuit, an absolute value circuit, a hysteresis circuit, and an output circuit.

(1) AC power supply

The liquid level sensor needs to be supplied with alternating current under the liquid level, however, the system is designed to be supplied with direct current through a unified interface, so that the liquid level sensor is supplied with power through an alternating current power supply in the embodiment. The alternating current power supply is a Direct Current (DC) to Alternating Current (AC) circuit, and the principle of the alternating current power supply is shown in fig. 2.

Firstly, an LMC555 timer (the principle of the LMC555 timer of this embodiment is shown in fig. 3) generates a square wave signal, and the frequency of the square wave signal is 1.44/(R) where f is 1.44_A+2R_B) C), duty cycle D ═ R_B/(R_A+2R_B). The square wave signal and the positive voltage signal pass through an AND gate and an NAND gate respectively to obtain two square wave signals with opposite phases, and the H-bridge chip is controlled by the opposite square wave signals, such as DRV8872 to output an alternating current power supply signal. When IN1 is 1 and IN2 is 0, SW1 is closed, SW2 is open, SW3 is open, and SW4 is closed, where CH + is +10V and CH-is ground. When IN1 is 0 and IN2 is 1, SW1 is off, SW2 is on, SW3 is on, and SW4 is off, where CH + is ground and CH-is + 10V.

(2) Acquisition circuit

The purpose of the acquisition circuit of this embodiment is to convert a differential signal into a single-ended signal, and the type of a specific chip is selected according to the actual design requirements. The acquisition circuit principle is shown in fig. 6.

(3) Absolute value circuit

The input signal of the present embodiment is a positive and negative single-ended signal after differential acquisition, and is processed into a positive signal by an absolute value circuit. The absolute value circuit is processed by a double operational amplifier chip OPA2140AIDGKT, and the chip has the characteristics of high precision, low noise, low offset, rail-to-rail output and the like. The absolute value specific circuit is shown in fig. 4.

When the input is a positive signal, the diode D4 is turned on, according to the principle of virtual short and virtual break of the operational amplifier:

the calculation is carried out according to the formula 1 and the formula 2: VOUT ═ VIN.

When the input signal VIN is a negative signal, the diode D4 is turned off, according to the principle of virtual short and virtual break of the operational amplifier:

calculated according to equation 3: VOUT ═ VIN.

(4) Hysteresis circuit

The hysteresis circuit of this embodiment sets up the hysteresis comparison to the level sensor signal according to the demand, prevents to make a round trip to shake. The module demand hysteresis interval is adjustable, specifically is:

gear 1: 80k omega-400 k omega: the liquid level is lower than or equal to 80k omega, the liquid level is higher than or equal to 400k omega, and the other states are uncertain.

Gear 2: 160k Ω -700 k Ω: the liquid level is below 160k omega or above 700k omega, and the other states are uncertain.

The analysis was as follows:

gear 1: when the liquid level probe contacts the liquid surface, the equivalent resistance is smaller than 80k omega, when the probe fluctuates towards the liquid surface, the equivalent resistance changes, when the equivalent resistance is close to 400k omega, the output state of the module is turned, and when the equivalent resistance is larger than 400k omega, the output state of the module is determined to be turned. When the probe fluctuates to the position below the liquid level and is close to 80k omega, the output state is reversed, and when the output state is smaller than 80k omega, the output state is determined to be reversed.

Gear 2: when the liquid level probe contacts the liquid surface, the equivalent resistance is smaller than 160k omega, when the probe fluctuates towards the liquid surface, the equivalent resistance changes, when the equivalent resistance is close to 700k omega, the output state of the module is turned, and when the equivalent resistance is larger than 700k omega, the output state of the module is determined to be turned. When the probe fluctuates to the position below the liquid level and approaches 160k omega, the output state is reversed, and when the output state is smaller than 160k omega, the output state is determined to be reversed.

Description of the drawings: when the gear is selected, the gear 1 can be selected only when the equivalent resistance of the probe under the liquid level is determined to be less than 80k omega, and the gear 2 can be selected only when the equivalent resistance of the probe under the liquid level is determined to be less than 160k omega.

As shown in fig. 5: the circuit is a hysteresis circuit, and the calculation method of the hysteresis threshold is as follows:

VREF _ COM is a reference voltage 4.096V generated by the reference source.

The calculation is carried out according to the formula 4 and the formula 5 to obtain: VTH ≈ 4.7V, VTL ≈ 2.46V.

When gear 1 is selected: the hysteresis interval is 80k omega-400 k omega, and in order to meet the requirement of the hysteresis interval, the resistors connected in series with the liquid level sensors need to be selected, as shown in fig. 6, that is, the resistance values of R30 and R31 are determined.

The equivalent resistance of the liquid level sensor is R_{Conveying appliance}。

When VTH is 4.7V, R_{Conveying appliance}When the absolute value of the ac power supply is 10V, 80k Ω is obtained, and R30+ R31 is 70.9k Ω. Considering the selection of devices, power supply errors and resistance, ensuring the resistance at R_{Conveying appliance}Under the condition of < 80k omega, the output is in a fixed state, the resistance value of R30+ R31 is designed according to 100k omega, and the condition is that when R is in the fixed state_{Conveying appliance}When the temperature is less than or equal to 112k omega, the sensor is under the liquid level. So when gear 1 is selected, R_{Conveying appliance}If < 80 k.OMEGA, it is definitely below the liquid level.

When VTL is 2.46V and R30+ R31 is 100k Ω, R_{Conveying appliance}306k Ω, i.e. R_{Conveying appliance}And when the output state of the module is larger than 306k omega, the output state of the module is turned to be a state on the liquid level, and when the requirement is met and is larger than 400k omega, the output state of the module is determined to be on the liquid level.

When gear 2 is selected: the hysteresis interval is 160k omega-700 k omega, and in order to meet the requirement of the hysteresis interval, the resistors connected in series with the liquid level sensors need to be selected, as shown in fig. 6, that is, the resistance values of R32 and R33 are determined.

When VTH is 4.7V, R_{Conveying appliance}When the absolute value of ac power supply is 10V, 160k Ω results in 141.8k Ω of R32+ R33. Considering the selection of devices, power supply errors and resistance, ensuring the resistance at R_{Conveying appliance}Under the condition of < 160k omega, the output is in a fixed state, the resistance value of R32+ R33 is designed to be 182k omega, and the condition is that when R is in the fixed state_{Conveying appliance}When the temperature is less than or equal to 205k omega, the sensor is under the liquid level. So when gear 2 is selected, R_{Conveying appliance}Below 160 kOmega, the liquid level is definitely below the liquid level.

When VTL is 2.46V and R32+ R33 is 182k Ω, R_{Conveying appliance}557k Ω, i.e. R_{Conveying appliance}When the output state of the module is larger than 557k omega, the output state of the module is turned to the state on the liquid level, and when the output state meets the requirement that the output state is larger than 700k omega, the output state is determined to be on the liquid level.

(5) Output circuit

The output circuit of this embodiment corresponds to the input signal, and the input signal corresponds an output state under the liquid level, and the input signal corresponds an output state on the liquid level. The output state can be configured through the dial switch, the output state can be flexibly configured according to the actual requirement of the rear-stage equipment, and the output state can be specifically configured as follows:

when the input is below the liquid level, the output can be configured as a contact closed or a contact open; the output may also be configured to be contact closed or contact open when the input is above the liquid level.

The embodiment has the advantage that the output contacts can be configured when the sensor is below the liquid level according to design requirements. The output contacts are controlled by a dip switch SW 2.

When legs 1, 8 and 2, 7 of SW2 are closed: the Vout signal passes through the current limiting resistor to directly control AQY222R1S to isolate the chip. When Vout is high, the sensor is below the liquid level, and the current through AQY222R1S control terminal is: i ═ 15V-1.1V)/2.7k Ω ═ 5.148mA, available according to the chip manual: AQY222R1S, the 3, 4 feet are closed. When Vout is low, no current passes through the control terminal AQY222R1S, and pins 3 and 4 of AQY222R1S are disconnected.

When legs 3, 6 and 4, 5 of SW2 are closed: the Vout signal controls the switching off of the transistor Q3, which operates in saturation, and when Vout is high, Q3 is turned on, i.e., the control terminal of AQY222R1S is low, i.e., pins 3 and 4 of AQY222R1S are turned off. When Vout is low, Q3 is open, i.e. the control terminal AQY222R1S is high, i.e. pins 3 and 4 of AQY222R1S are closed.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer programs may be provided to a processor of a general purpose computer, special purpose computer, embedded processor or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

The above-mentioned embodiments, objects, technical solutions and advantages of the present invention are further described in detail, it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.