A monitoring alarm circuit with protection and self-recovery functions

Abstract

The present invention provides a monitoring alarm circuit with protection and self-recovery functions, comprising: a sensor (1) for acquiring monitoring data; an alarm circuit (7) for prompting that the monitoring data exceeds a standard; an MCU (2) connected to the sensor and the alarm circuit and used to receive the monitoring data and control the alarm circuit; a current sampling element (8) for acquiring current data of the alarm circuit; a monostable trigger (9) connected to the current sampling element; and a logic operation unit (5) connected between the alarm circuit and the MCU and connected to the output end of the monostable trigger. The monitoring alarm circuit of the present invention can automatically limit the current after the current of the alarm circuit exceeds a standard, thereby protecting the sensor and the circuit. And it can automatically recover after the current of the alarm circuit returns to normal, without manual recovery.

Description

Technical Field

[0001] The invention relates to a monitoring alarm circuit, in particular to a monitoring alarm circuit with protection and self-recovery functions. Background Art

[0002] like Figure 1 As shown, the existing monitoring alarm circuit is composed of a sensor 1 for obtaining monitoring data; an alarm circuit 7 for prompting that the monitoring data exceeds the standard; an MCU2 connected to the sensor 1 and the alarm circuit 7, for receiving the monitoring data and controlling the alarm circuit 7, and an isolation element 6 connected between the MCU2 and the alarm circuit 7 for separating strong current from weak current. The isolation element 6 is usually an optocoupler, a triode, etc. When the monitoring data exceeds the standard, the MCU2 controls the alarm circuit 7 to generate a prompt message, thereby realizing the monitoring alarm function. Among them, the current and power consumption in the alarm circuit 7 are determined by the system environment in which the sensor 1 is used. When the system is abnormal or fails, a large current may appear in the alarm circuit 7, thereby damaging the sensor 1 or even the entire monitoring alarm circuit.

[0003] Therefore, there is an urgent need for a monitoring alarm circuit with protection and self-recovery functions. Summary of the invention

[0004] The purpose of the present invention is to provide a monitoring alarm circuit with protection and self-recovery functions to solve the above-mentioned defects in the prior art.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A monitoring alarm circuit with protection and self-recovery functions, comprising:

[0007] Sensors for acquiring monitoring data;

[0008] An alarm circuit for indicating that the monitoring data exceeds the standard;

[0009] An MCU connected to the sensor and the alarm circuit and used to receive the monitoring data and control the alarm circuit;

[0010] A current sampling element for acquiring current data of the alarm circuit;

[0011] A monostable trigger connected to the current sampling element, whose output level flips and enters a transient state from a steady state when the current data exceeds the standard;

[0012] A logic operation unit connected between the alarm circuit and the MCU and to the output end of the monostable trigger, used for performing logic operations on the levels from the MCU and the levels from the monostable trigger, thereby controlling the alarm circuit so that the alarm circuit outputs alarm information after the monitoring data exceeds the standard and intermittently shuts off the alarm circuit to limit the current data after the current data exceeds the standard.

[0013] When the monitoring data exceeds the standard, the MCU outputs the control level, the logic operation unit controls the alarm circuit to be turned on, and generates an alarm message to prompt that the monitoring data exceeds the standard. When the current of the alarm circuit increases and exceeds the standard, the input of the monostable trigger changes, causing its output level to flip and maintain for a short time before recovering again (that is, the monostable trigger works in a transient state). After the logic operation of the logic operation unit, the alarm circuit is controlled to be turned off for a short time and then turned on again. Before the current of the alarm circuit returns to normal, the above process will be automatically repeated, thereby achieving the purpose of limiting the current of the alarm circuit and protecting the circuit. When the current of the alarm circuit returns to normal, the input of the monostable trigger maintains a state unchanged, and the monostable trigger enters a steady state, thereby realizing the automatic recovery of the monitoring alarm circuit.

[0014] Preferably, the logic operation unit is an AND gate.

[0015] Preferably, the monitoring alarm circuit further comprises a prompting unit for prompting that the current data exceeds a standard.

[0016] Preferably, the prompt unit is a first LED connected to the output end of the monostable trigger. After the current data exceeds the standard, the first LED flashes and the flashing frequency becomes faster as the current data increases. When the current data increases to a certain value, the first LED continues to emit light.

[0017] Preferably, the monitoring alarm circuit further comprises a display unit connected to the MCU for displaying the monitoring data.

[0018] Preferably, an isolation element for isolating strong electricity from weak electricity is provided between the alarm circuit and the logic operation unit.

[0019] Preferably, an isolation element for isolating strong current from weak current is provided between the monostable trigger and the current sampling element.

[0020] Preferably, the isolation element is an optical coupler.

[0021] Preferably, the sensor is a pressure sensor, and the monitoring alarm circuit includes two alarm circuits, two current sampling elements, two monostable triggers, and two logic operation units, which can automatically prompt, provide overcurrent protection, and automatically recover when the high voltage or low voltage exceeds the standard.

[0022] Compared with the prior art, the present invention has at least the following beneficial effects:

[0023] The monitoring alarm circuit of the present invention can automatically limit the current after the current of the alarm circuit exceeds the standard, thereby protecting the sensor and the circuit, and can automatically recover after the current of the alarm circuit returns to normal without manual recovery. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is the principle block diagram of the existing monitoring alarm circuit;

[0025] Figure 2 It is a principle block diagram of the first embodiment of the monitoring alarm circuit with protection and self-recovery functions of the present invention;

[0026] Figure 3 It is a principle block diagram of the second embodiment of the monitoring alarm circuit with protection and self-recovery functions of the present invention;

[0027] Figure 4 It is the circuit diagram of MCU, display unit and prompt unit;

[0028] Figure 5 It is a circuit diagram of a current sampling element, a monostable trigger, a logic operation unit, and an alarm circuit;

[0029] Figure numerals: 1. sensor; 2. MCU; 3. display unit; 4. prompt unit; 5. logic operation unit; 6. isolation element; 7. alarm circuit; 8. current sampling element; 9. monostable trigger; 10. 100V-24V power converter; 11. 24V-3.3V power converter; 12. RC timing element. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0031] First embodiment:

[0032] Please refer to Figure 2The monitoring alarm circuit with protection and self-recovery functions includes: a sensor 1 for obtaining monitoring data; an alarm circuit 7 for prompting that the monitoring data exceeds the standard; an MCU2 connected to the sensor 1 and the alarm circuit 7, for receiving the monitoring data and controlling the alarm circuit 7; a current sampling element 8 for obtaining current data of the alarm circuit 7; a monostable trigger 9 connected to the current sampling element 8, whose output level flips and enters a transient state from a steady state when the current data exceeds the standard; a logic operation unit 5 connected between the alarm circuit 7 and the MCU2 and connected to the output end of the monostable trigger 9, for performing logical operations on the levels from the MCU2 and the levels from the monostable trigger 9, and then controlling the alarm circuit 7 so that the alarm circuit 7 outputs an alarm message after the monitoring data exceeds the standard and the alarm circuit 7 is intermittently shut down after the current data exceeds the standard to limit the current data.

[0033] Its working principle is as follows: when the monitoring data exceeds the standard, MCU2 outputs the control level, the logic operation unit 5 controls the alarm circuit 7 to be turned on, and generates an alarm message to prompt that the monitoring data exceeds the standard. When the current of the alarm circuit 7 increases and exceeds the standard, the input of the monostable trigger 9 changes, causing its output level to flip and be briefly maintained before being restored again (i.e., the monostable trigger 9 works in a transient state). After the logic operation of the logic operation unit 5, the alarm circuit 7 is controlled to be briefly turned off and then turned on again. Before the current of the alarm circuit 7 returns to normal, the above process will be automatically repeated, that is, the alarm circuit 7 will be intermittently judged, thereby achieving the purpose of limiting the current of the alarm circuit 7 and protecting the circuit. When the current of the alarm circuit 7 returns to normal, the input of the monostable trigger 9 maintains a state unchanged, the monostable trigger 9 enters a steady state, and continuously outputs a high level, thereby realizing the automatic recovery of the monitoring alarm circuit.

[0034] The monitoring alarm circuit further includes a prompting unit 4 for prompting that the current data exceeds the standard. The prompting unit 4 can be any one or more of a sounding device, a light-emitting device, and a display device. The prompting unit 4 is preferably connected to the output end of the monostable trigger 9, and preferably an LED. Since the monostable trigger 9 works in a transient state after the current data (i.e., the current of the alarm circuit 7) exceeds the standard, the LED connected to the output end of the monostable trigger 9 works in a flashing state. The larger the current of the alarm circuit 7, the higher the frequency of the monostable trigger 9 entering the transient state, and the higher the flashing frequency of the LED. When the current data increases to a certain value, the LED continues to emit light. Therefore, through this solution, the staff can intuitively judge the severity of the current exceeding the standard through the LED flashing frequency.

[0035] The monitoring alarm circuit further includes a display unit 3 connected to the MCU2 for displaying the monitoring data.

[0036] An isolation element 6 for isolating strong current from weak current is further provided between the alarm circuit 7 and the logic operation unit 5. An isolation element 6 for isolating strong current from weak current is provided between the monostable trigger 9 and the current sampling element 8. The isolation element 6 is preferably an optical coupler.

[0037] Second embodiment:

[0038] Please refer to Figure 3 The monitoring alarm circuit with protection and self-recovery functions includes: a sensor 1 for obtaining monitoring data; an alarm circuit 7 for prompting that the monitoring data exceeds the standard; an MCU2 connected to the sensor 1 and the alarm circuit 7, for receiving the monitoring data and controlling the alarm circuit 7; a current sampling element 8 for obtaining current data of the alarm circuit 7; a monostable trigger 9 connected to the current sampling element 8, whose output level flips and enters a transient state from a steady state when the current data exceeds the standard; a logic operation unit 5 connected between the alarm circuit 7 and the MCU2 and connected to the output end of the monostable trigger 9, for performing logical operations on the levels from the MCU2 and the levels from the monostable trigger 9, and then controlling the alarm circuit 7 so that the alarm circuit 7 outputs an alarm message after the monitoring data exceeds the standard and the alarm circuit 7 is intermittently shut down after the current data exceeds the standard to limit the current data.

[0039] The sensor 1 is a pressure sensor 1 and has two alarm circuits 7, two current sampling elements 8, two monostable triggers 9, and two logic operation units 5, which form two groups. Figure 3 Each dotted box in the figure is a group, and the two groups are used to monitor and alarm the high pressure and low pressure respectively, so that automatic prompts, over-current protection and automatic recovery can be provided when the high pressure exceeds the standard or the low pressure exceeds the standard.

[0040] The monitoring alarm circuit further includes a prompting unit 4 for prompting that the current data exceeds the standard. The prompting unit 4 can be any one or more of a sounding device, a light-emitting device, and a display device. The prompting unit 4 is preferably connected to the output end of the monostable trigger 9, and preferably an LED. Since the monostable trigger 9 works in a transient state after the current data (i.e., the current of the alarm circuit 7) exceeds the standard, the LED connected to the output end of the monostable trigger 9 works in a flashing state. The larger the current of the alarm circuit 7, the higher the frequency of the monostable trigger 9 entering the transient state, and the higher the flashing frequency of the LED. When the current data increases to a certain value, the LED continues to emit light. Therefore, through this solution, the staff can intuitively judge the severity of the current exceeding the standard through the LED flashing frequency.

[0041] The monitoring alarm circuit further includes a display unit 3 connected to the MCU2 for displaying the monitoring data.

[0042] An isolation element 6 for isolating strong current from weak current is further provided between the alarm circuit 7 and the logic operation unit 5. An isolation element 6 for isolating strong current from weak current is provided between the monostable trigger 9 and the current sampling element 8.

[0043] Figure 4 and Figure 5 The specific circuit is shown. Figure 4 The circuit includes MCU2, display unit 3, prompt unit 4 and 24V-3.3V power converter 11, Figure 5 The circuit includes a current sampling element 8, a monostable trigger 9, a logic operation unit 5, an alarm circuit 7, and a 100V-24V power converter 10.

[0044] Please refer to Figure 4 MCU2 uses a chip of model PIC 16F1782, the display unit 3 is a four-digit digital tube, and the prompt unit 4 includes two groups of LEDs, one group corresponds to high voltage, and the other group corresponds to low voltage. Each group includes two LEDs, one LED is connected to the output end of the monostable trigger 9 to prompt that the current of the alarm circuit 7 exceeds the standard, and the other LED is connected to MCU2 to prompt that the pressure (that is, the data monitored by the sensor) exceeds the standard. Figure 4 The middle IN terminal is used to connect sensor 1. The current signal output by the sensor is converted into a voltage signal by the chip OPA347 and input into MCU2. The 24V-3.3V power converter 11 is composed of a transistor, a chip AZ432, etc., which converts 24V DC into 3.3V to power MCU2 and other chips.

[0045] Please refer to Figure 5 , one alarm circuit 7 includes a transistor Q1 and a resistor R3, and the resistor R3 constitutes a current sampling element 8 of the alarm circuit. Another alarm circuit 7 includes a transistor Q3 and a resistor R6, and the resistor R6 constitutes a current sampling element 8 of the alarm circuit. The monostable trigger 9 adopts a chip 74HC123, which includes two monostable triggers. In this embodiment, the logic operation unit 5 is specifically an AND gate, which adopts a chip 74LVC2G08. The isolation element 6 adopts an optocoupler.

[0046] Its working principle is as follows: pressure sensor 1 monitors pressure data, inputs into MCU2, and then displays pressure data through four-digit digital tube (display unit 3). When the pressure data exceeds the lower limit, MCU2 outputs alarm level ALM1 (high level), which controls the LED light to light up to generate prompt information, and transmits to AND gate (logic operation unit 5) on the other hand. AND gate outputs high level, controls transistor Q1 to conduct after isolation by optocoupler U2, and turns on alarm circuit 7. When the current of the alarm circuit 7 increases beyond the standard, the transistor Q2 is turned on, and the input of the monostable trigger 9 is changed by controlling the optocoupler U3. The output level of the monostable trigger 9 is flipped from the high level to the low level and restored to the high level again after a short maintenance, so that the output of the AND gate is changed to the low level and restored to the high level again after a short maintenance, thereby causing the transistor Q1 in the alarm circuit 7 to be temporarily disconnected (the disconnection time can be flexibly designed by designing the RC timing element 12 outside the monostable trigger 9). Before the current of the alarm circuit 7 returns to normal, the above process will be automatically repeated, thereby achieving the purpose of limiting the current of the alarm circuit 7 and protecting the circuit. In addition, in the above process, the output of the monostable trigger 9 is a pulse signal, and the frequency of the pulse signal increases with the increase of the current of the alarm circuit 7. In this way, the degree of the current exceeding the standard of the alarm circuit 7 can be intuitively known by the speed of the LED (prompt unit 4) flashing. When the current of the alarm circuit 7 returns to normal, the input of the monostable trigger 9 maintains a state unchanged, the monostable trigger 9 enters a steady state, and continuously outputs a high level, thereby realizing the automatic recovery of the monitoring alarm circuit.

[0047] When the pressure data exceeds the upper limit, MCU2 outputs the alarm level ALM2 and controls another circuit to realize the alarm. The principle is the same as that when it exceeds the lower limit, so it will not be repeated here.

[0048] The above monitoring and alarm circuit can be integrated on a circuit board and connected with corresponding sensors to form a monitoring and alarm device, for example: connected with a pressure sensor to form a pressure gauge, connected with a temperature sensor to form a temperature monitoring device, and so on.

[0049] The present invention is described in detail above through specific embodiments, and these detailed descriptions are only limited to helping those skilled in the art understand the content of the present invention, and cannot be understood as limiting the scope of protection of the present invention. Various modifications, equivalent transformations, etc. made by those skilled in the art to the above scheme under the conception of the present invention should be included in the scope of protection of the present invention.

Claims

1. A monitoring alarm circuit with protection and self-recovery functions, comprising: A sensor (1) for acquiring monitoring data; An alarm circuit (7) for indicating that the monitoring data exceeds the standard; An MCU (2) connected to the sensor (1) and the alarm circuit (7) and used for receiving the monitoring data and controlling the alarm circuit (7); It is characterized by further comprising: A current sampling element (8) for acquiring current data of the alarm circuit (7); A monostable trigger (9) connected to the current sampling element (8) and having its output level flipped and entering a transient state from a steady state when the current data exceeds the standard; A logic operation unit (5) connected between the alarm circuit (7) and the MCU (2) and connected to the output end of the monostable trigger (9), and used for performing a logic operation on the level from the MCU (2) and the level from the monostable trigger (9) to control the alarm circuit (7) so that the alarm circuit (7) outputs an alarm message when the monitoring data exceeds the standard and the alarm circuit (7) is intermittently turned off to limit the current data when the current data exceeds the standard; Wherein, the logic operation unit (5) is an AND gate; The monitoring alarm circuit also includes a prompting unit (4) for prompting that the current data exceeds the standard.

2. The monitoring alarm circuit with protection and self-recovery functions according to claim 1 is characterized in that: The prompt unit (4) is a first LED connected to the output end of the monostable trigger (9). When the current data exceeds the standard, the first LED flashes and the flashing frequency becomes faster as the current data increases. When the current data increases to a certain value, the first LED continues to emit light.

3. The monitoring alarm circuit with protection and self-recovery functions according to claim 1 is characterized in that: The monitoring alarm circuit also includes a display unit (3) connected to the MCU (2) and used for displaying the monitoring data.

4. The monitoring alarm circuit with protection and self-recovery functions according to claim 1 is characterized in that: An isolation element (6) for isolating strong electricity from weak electricity is provided between the alarm circuit (7) and the logic operation unit (5).

5. The monitoring alarm circuit with protection and self-recovery functions according to claim 1 is characterized in that: An isolation element (6) for isolating strong current from weak current is arranged between the monostable trigger (9) and the current sampling element (8).

6. The monitoring alarm circuit with protection and self-recovery functions according to claim 4 or 5, characterized in that: The isolation element (6) is an optical coupler.

7. The monitoring alarm circuit with protection and self-recovery functions according to claim 1 is characterized in that: The sensor (1) is a pressure sensor, and the monitoring alarm circuit comprises two alarm circuits (7), two current sampling elements (8), two monostable triggers (9), and two logic operation units (5), and can automatically prompt, provide overcurrent protection, and automatically recover when the high voltage exceeds the standard or the low voltage exceeds the standard.

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