Electromagnetic water meter power consumption tester

Abstract

The utility model relates to the technical field of electromagnetic water meters, and discloses an electromagnetic water meter power consumption tester which comprises a control circuit, the input end of the control circuit is connected with an amplifying circuit and an excitation time sequence sampling circuit, and the output end of the control circuit is connected with a display circuit. The input end of the amplification circuit is connected with the sampling resistor and the excitation time sequence sampling circuit, excitation output signals are collected through the excitation time sequence sampling circuit, ADC sampling and the excitation output signals are synchronized, and excitation current can be accurately measured; meanwhile, the maximum measurement current is limited to be 50 mA, the measurement precision is higher in the low-current range, the resolution ratio is better, and the method is more suitable for power consumption measurement of the electromagnetic water meter.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of electromagnetic water meter, more specifically, the utility model relates to a kind of electromagnetic water meter power consumption tester. BACKGROUND

[0002] As a kind of equipment for measuring water flow, the power consumption of electromagnetic water meter is relatively low, and the average power consumption is usually below 1mA, while the excitation power consumption is about 20mA. This requires the test equipment to accurately measure low current to ensure the accuracy and reliability of the water meter.

[0003] Traditional power consumption tester is designed to measure a larger range of current, usually above 1A, which is far from the actual power consumption of electromagnetic water meter, resulting in insufficient accuracy when measuring low current, and unable to measure excitation current alone, limiting the evaluation of the performance of electromagnetic water meter excitation part, resulting in insufficient measurement accuracy and resolution to meet the precise measurement requirements of electromagnetic water meter.

[0004] Therefore, the utility model provides a kind of electromagnetic water meter power consumption tester. UTILITY MODEL CONTENTS

[0005] To overcome the problems in the prior art, the utility model provides a kind of electromagnetic water meter power consumption tester, which has higher measurement accuracy and better resolution in the low current range, and is more suitable for power consumption measurement of electromagnetic water meter.

[0006] According to one aspect of the utility model, a kind of electromagnetic water meter power consumption tester is provided, including control circuit, the control circuit input end connection amplification circuit and excitation timing sampling circuit, the control circuit output end connection display circuit, the amplification circuit connection input end connection sampling resistance and excitation timing sampling circuit, wherein;

[0007] The sampling resistance includes sampling resistance R36 and sampling resistance R40, and the size of sampling resistance R36 and sampling resistance R40 is 1 ohm;

[0008] The amplification circuit includes operational amplifier U1, and the operational amplifier U1 is a differential amplifier for amplifying real-time current signal filtered from sampling resistance R36. Resistor R25 and resistor R28 are connected between sampling resistance R36 and operational amplifier U1, and the gain of operational amplifier U1 is set based on resistor R25 and resistor R28.

[0009] The excitation timing sampling circuit comprises an ADC converter and an operational amplifier U2, the operational amplifier U2 is used for synchronizing the ADC sampling and the excitation output signal, and isolating the ADC converter input and the front-stage circuit; the ADC converter comprises two channels, and the two channels are connected with ADC channel 1 and ADC channel 2 output by the operational amplifier U1 and the operational amplifier U2 respectively, so that two different analog signals can be processed simultaneously.

[0010] As a preferred technical scheme of the utility model, the utility model also discloses a power supply battery, the power supply battery is connected with the sampling resistor, the amplification circuit, the excitation timing sampling circuit, the control circuit and the display circuit respectively, the power supply battery is 3.6V lithium battery, and power is provided based on the 3.6V lithium battery.

[0011] As a preferred technical scheme of the utility model, the utility model also discloses that the ground circuit in the analog circuit and the ground circuit in the digital circuit are isolated,

[0012] As a preferred technical scheme of the utility model, the utility model also discloses a filter capacitor for carrying out power decoupling treatment on the power supply battery, and the filter capacitor comprises capacitor C5, capacitor CB7, capacitor CB10, capacitor CB11 and capacitor CB6.

[0013] As a preferred technical scheme of the utility model, the input voltage range of the ADC converter is adjusted through resistance RB8 and resistance R40.

[0014] As a preferred technical scheme of the utility model, 2P wiring terminal P1 is a power supply terminal, and power support is provided based on 2P wiring terminal P1; 2P wiring terminal P2 is an excitation sampling terminal, and the excitation output signal is received based on 2P wiring terminal P2.

[0015] The technical effect and advantages of the electromagnetic water meter power consumption tester are as follows:

[0016] The utility model discloses a excitation timing sampling circuit gathers excitation output signal, realizes ADC sampling and excitation output signal synchronization, can accurately measure excitation current, and simultaneously limits the maximum measured current at 50mA, and the measurement precision is higher in the low current range, the resolution is better, and the electromagnetic water meter is more applicable to power consumption measurement. DRAWINGS

[0017] Figure 1 It is the system structure schematic drawing of the electromagnetic water meter power consumption tester in the utility model embodiment;

[0018] Figure 2 It is the circuit connection diagram of the electromagnetic water meter power consumption tester in the utility model embodiment;

[0019] Figure 3The utility model discloses an external circuit diagram of reference voltage REF in the embodiment of the utility model.

[0020] Reference signs:

[0021] 1, pipe section;

[0022] 2, sampling resistance;

[0023] 3, amplification circuit;

[0024] 4, excitation timing sampling circuit;

[0025] 5, control circuit;

[0026] 6, display circuit. Specific implementation

[0027] The technical scheme in the embodiment of the utility model will be clearly and completely described below with reference to the drawings in the embodiment of the utility model. Obviously, the described embodiment is only a part of the embodiment of the utility model, not all the embodiment. Based on the embodiment in the utility model, all other embodiments obtained by the ordinary skill in the art without creative labor belong to the protection scope of the utility model.

[0028] Embodiment 1

[0029] Please refer to Figure 1 The utility model discloses an electromagnetic water meter power consumption tester, including control circuit 5, the control circuit 5 input end connects amplification circuit 3 and excitation timing sampling circuit 4, the control circuit 5 output end connects display circuit 6;

[0030] Based on amplification circuit 3 real-time acquisition electromagnetic water meter control panel real-time current;

[0031] Based on excitation timing sampling circuit 4 acquisition excitation output signal, realize ADC sampling and excitation output signal synchronization obtains excitation current;

[0032] Control circuit 5, real-time current and excitation current are input simultaneously, with excitation current as the reference value of real-time current, obtains electromagnetic water meter power consumption test result, and electromagnetic water meter power consumption test result is shown through display circuit 6.

[0033] The amplification circuit 3 is connected to the input end and is connected to the sampling resistance 2 and the excitation timing sampling circuit 4.

[0034] The sampling resistance 2 includes sampling resistance R36 and sampling resistance R40, and the size of the sampling resistance R36 and the sampling resistance R40 is 1 ohm.

[0035] The amplification circuit 3 includes an operational amplifier U1, which is a differential amplifier, for amplifying the real-time current signal filtered from the sampling resistor R36; a resistor R25 and a resistor R28 are connected between the sampling resistor R36 and the operational amplifier U1, the gain of the operational amplifier U1 is set based on the resistor R25 and the resistor R28, and the high-frequency noise in the signal is removed through filtering by a capacitor C3 and a capacitor C4; the voltage signal on the sampling resistor is amplified to a range suitable for ADC sampling, while maintaining a high resolution. For example, the voltage (0-50mV) on the 1 ohm sampling resistor 2 is amplified by 50.4 times, about 0-2.5V, which not only fits the sampling range of 3.3V ADC, but also provides a higher resolution.

[0036] The excitation timing sampling circuit (4) includes an ADC converter and an operational amplifier U2 for synchronizing the ADC sampling with the excitation output signal and isolating the ADC converter input and the previous stage circuit; the ADC converter includes two channels, ADC channel 1 and ADC channel 2 connected to the outputs of the operational amplifier U1 and the operational amplifier U2 respectively, which can process two different analog signals simultaneously.

[0037] The excitation current is converted into a square wave voltage signal with 1.29V as the reference, and compared with the reference voltage 1.25V through a comparator to obtain the excitation timing signal. This processing method not only improves the stability of the signal, but also facilitates subsequent digital processing. The control circuit reads this digital signal, calculates the flow according to the preset algorithm, and displays or sends it out through the display or communication module.

[0038] Specifically, the operational amplifier U1 is an AD8221 chip; the operational amplifier U2 is an ALM293D chip; and the ADC converter is an AMC 1200BDWR chip.

[0039] It should be noted that the average power consumption of a conventional electromagnetic water meter is below 1mA, and the excitation power consumption is about 20mA. The maximum measurement current of a conventional power consumption tester is generally above 1A, which is quite different from the actual power consumption of an electromagnetic water meter; at the same time, it is also impossible to measure the excitation current of an electromagnetic water meter alone. The present embodiment is specially optimized for the actual characteristics of an electromagnetic water meter, the excitation output signal is collected through the excitation timing sampling circuit 4, the ADC sampling is synchronized with the excitation output signal, the excitation current can be accurately measured; at the same time, the maximum measurement current is limited to 50mA, the measurement accuracy is higher in the low current range, the resolution is better, and it is more suitable for the power consumption measurement of an electromagnetic water meter.

[0040] Further, the power supply battery 1 is connected to the sampling resistor 2, the amplification circuit 3, the excitation time sequence sampling circuit 4, the control circuit 5 and the display circuit 6 respectively, the power supply battery 1 is a 3.6V lithium battery, and power is provided based on the 3.6V lithium battery.

[0041] Specifically, the ground line in the analog circuit is isolated from the ground line in the digital circuit, the power supply and the ground of the analog circuit are used respectively, the ground of the digital circuit is represented as GND2, the analog ground AGND is distinguished, and the noise interference is reduced.

[0042] Further, the 2P terminal P1 provides power support; the 2P terminal P1 is a power supply terminal, the 2P terminal P2 is an excitation sampling terminal, and the excitation output signal is received based on the 2P terminal P2; the excitation output signal is converted into a digital signal through the coordinated processing of the operational amplifier U1, the operational amplifier U2, the operational amplifier U3 and the ADC converter, and the digital signal is processed by the control circuit and can be used for display, recording or further control operation.

[0043] As Figure 2 A specific example is provided to illustrate that the power consumption tester provided by the embodiment provides a 3.3V lithium battery for the electromagnetic water meter control board, the ground of the electromagnetic water meter control board is grounded through a 1-ohm sampling resistor R36, the signal of the sampling resistor R36 is input into the ADC channel 1 after being amplified by the amplification circuit U1; the voltage sampled on the ADC channel 1 is divided by the amplification multiple and then divided by the 1-ohm sampling resistor, which is the real-time current of the electromagnetic water meter control board.

[0044] It should be noted that the working current of the electromagnetic water meter control board is generally in the range of 0-50mA, so the voltage on the 1-ohm sampling resistor R36 is about 0-50mV, which is about 0-2.5V after being amplified by 50.4 times, which is just within the sampling range of the 3.3V ADC and has a high resolution.

[0045] The electromagnetic water meter control board provides an excitation signal for the electromagnetic water meter sensor coil through the excitation output, and one of the excitation lines needs to be connected to the power consumption tester when the power consumption tester is working, and then connected back to the electromagnetic water meter sensor through a 1-ohm sampling resistor R40; the signal on the sampling resistor R40 is input into the ADC channel 2 after being amplified by the amplification circuit U2; the voltage sampled on the ADC channel 2 is divided by the amplification multiple and then divided by the 1-ohm sampling resistor R40, which is the excitation current of the electromagnetic water meter control board.

[0046] AMC1200 is an isolation amplifier, when the power supply is 3.3V, the output is a differential signal with 1.29V as the reference. Because the excitation current is a positive and negative square wave current signal, the signal output after being amplified by AMC1200 is a square wave voltage signal with 1.29V as the reference. The amplification factor of AMC1200 is 8, and the excitation current is generally about 20mA, so the amplitude of the square wave voltage signal is 20mV*8=160MV, and the high value of the square wave voltage is 1.29+0.16=1.45V, and the low value is 1.29-0.16=1.13V. The square wave voltage is compared with the reference voltage 1.25V through the comparator, and the excitation timing signal is obtained; when the power consumption instrument controller detects the excitation timing signal, it will start sampling ADC channel 2 synchronously, and the excitation current of the electromagnetic water meter is obtained.

[0047] As shown in Figure 3 The operational amplifier U3 (TLV2211) is a low-power and low-offset voltage operational amplifier, which is used to generate a stable reference voltage, and a stable 1.25V reference voltage is generated from the AVCC (3.3V) power supply through the voltage division network of resistors R13 and R12. This voltage is used as a reference for other circuit parts, such as the reference voltage of the ADC converter.

[0048] Among them: resistors R13 and R12 form a voltage divider, which determines the value of the output reference voltage. According to the resistance ratio, the reference voltage can be calculated to provide a stable reference potential and reduce noise interference.

[0049] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited to this. Any skilled person in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be limited by the protection scope of the claims.

[0050] Finally: the above is only a preferred embodiment of the present application and is not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. An electromagnetic water meter power consumption tester, characterized in that, The utility model provides an electromagnetic water meter power consumption tester, including control circuit (5), control circuit (5) input end connects amplification circuit (3) and excitation timing sampling circuit (4), control circuit (5) output end connects display circuit (6), amplification circuit (3) connects input end connection sampling resistance (2) and excitation timing sampling circuit (4), wherein; The sampling resistance (2) includes a sampling resistance R36 and a sampling resistance R40, and the sizes of the sampling resistance R36 and the sampling resistance R40 are 1 ohm. The amplification circuit (3) includes an operational amplifier U1, which is a differential amplifier for amplifying the real-time current signal filtered from the sampling resistance R36. Between the sampling resistance R36 and the operational amplifier U1, there are a resistor R25 and a resistor R28, which set the gain of the operational amplifier U1. The excitation timing sampling circuit (4) includes an ADC converter and an operational amplifier U2, which is used to synchronize the ADC sampling and the excitation output signal, and isolate the ADC converter input and the previous stage circuit. The ADC converter includes two channels, which are respectively connected to the ADC channel 1 and the ADC channel 2 output by the operational amplifier U1 and the operational amplifier U2, and can process two different analog signals at the same time.

2. The electromagnetic water meter power consumption tester according to claim 1, wherein, It also includes a power supply battery (1) connected to the sampling resistance (2), the amplification circuit (3), the excitation timing sampling circuit (4), the control circuit (5), and the display circuit (6). The power supply battery (1) is a 3.6V lithium battery, which provides power based on the 3.6V lithium battery.

3. The electromagnetic water meter power consumption tester according to claim 1, wherein, It also includes isolating the ground circuit in the analog circuit from the ground circuit in the digital circuit.

4. The electromagnetic water meter power consumption tester according to claim 1, wherein, It also includes a filter capacitor for power decoupling processing of the power supply battery (1), which includes a capacitor C5, a capacitor CB7, a capacitor CB10, a capacitor CB11, and a capacitor CB6.

5. The electromagnetic water meter power consumption tester according to claim 1, wherein, The input voltage range of the ADC converter is adjusted by a resistor RB8 and a resistor R40.

6. The electromagnetic water meter power consumption tester according to claim 1, wherein, The 2P terminal P1 is a power supply terminal, which provides power support based on the 2P terminal P1. The 2P terminal P2 is an excitation sampling terminal, which receives the excitation output signal based on the 2P terminal P2.

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