CN205353342U - Single -phase carrier wave smart electric meter communication module interface load bearing capability tester - Google Patents

Abstract

A single-phase carrier smart meter communication module interface loading capacity tester, the tester includes a voltage control circuit, D/A converter, DSP, MOSFET circuit, current detection unit, voltage detection unit, single-phase power supply, A/ D converter, PC, resistor R1 and resistor R2. The utility model controls the gate-source voltage of the MOSFET circuit through a DSP and a voltage control circuit on the basis of detecting the drain current and the drain-source voltage of the MOSFET circuit, so as to obtain a load whose resistance value and accuracy meet the measurement requirements. Finally, through the DSP, the voltage value between the power supply Vcc terminal and the ground of the power supply for the communication module provided by the interface of the ammeter module is obtained, and the automatic detection of the load capacity of the interface of the communication module of the single-phase carrier smart ammeter is realized. The utility model is suitable for testing the load capacity of the interface of the single-phase carrier intelligent electric meter communication module.

Description

A single-phase carrier smart meter communication module interface loading capacity tester

technical field

The utility model relates to a single-phase carrier intelligent electric meter communication module interface loading capacity tester, which belongs to the technical field of intelligent electric meter testing.

Background technique

The carrier smart meter is equipped with a communication module interface, and a communication module is installed on the communication module interface, so that the communication with the concentrator can be realized in the form of a carrier wave through the power line. However, in field operation, it is found that the communication failure between the meter and the concentrator will occur due to the mismatch between the load capacity of the interface of the communication module of the meter and the power consumption of the carrier module. When the load capacity of the interface of the communication module of the ammeter is insufficient, the normal operation of the communication module cannot be driven; when the load capacity of the interface of the communication module of the ammeter exceeds the allowable range, the power consumption of the ammeter itself will be too large. For this reason, the State Grid Corporation of China has put forward corresponding requirements for the load capacity of the single-phase carrier smart meter communication interface. The State Grid Enterprise Standard "Q/GDW1364-2013 Single-phase Smart Meter Technical Specifications" stipulates that the V _CC voltage is at +12V± In the range of 1V, the load current should be in the range of 0mA～125mA.

At present, the detection of the load capacity of the interface of the communication module of the single-phase carrier smart energy meter mainly adopts the following method, that is, first remove the communication module installed in the energy meter, and then the indirect resistance between the power supply for the module and the ground at the interface of the communication module of the energy meter is 96Ω (± 5% accuracy) pure resistive load, and finally use a multimeter to detect the voltage value at the two ends of the place, and observe whether the voltage is within the range of 12V±1V. This method requires manual operation, which is time-consuming and error-prone. When the number of test items is large, it becomes more cumbersome. Moreover, in this method, the resistance value of the resistor between the power supply and the ground is susceptible to change due to factors such as temperature, thereby causing inaccurate detection results.

Contents of the invention

The purpose of the utility model, in order to overcome the deficiencies of the prior art, provides a single-phase carrier smart meter communication module interface load capacity tester, which is used to automatically detect the load capacity of the single-phase carrier smart meter communication module interface.

In order to solve the above technical problems, the utility model is realized through the following technical solutions: a single-phase carrier smart meter communication module interface load capacity tester, including: voltage control circuit, D/A converter, DSP, MOSFET circuit, Current detection unit, voltage detection unit, single-phase power supply, A/D converter, PC, resistor R1 and resistor R2.

The single-phase power supply is connected to the ammeter under test to provide power to the ammeter under test; the resistor R1 and the resistor R2 are connected in series, and connected between the power supply V _CC and the ground of the power supply V CC for the communication module at the interface of the ammeter module; the input terminal of the voltage detection unit is connected to At both ends of the resistor R2; the output terminal of the voltage detection unit passes through the A/D converter, converts the analog signal of the detected voltage into a digital signal, and transmits it to the DSP; the drain of the MOSFET circuit is connected to the V _CC terminal of the module interface in the meter , its source is connected to the ground of the meter module interface through the current detection unit; the current detection unit detects the drain current of the MOSFET circuit, and its output terminal passes through the A/D converter to convert the detected analog signal of the gate current of the MOSFET circuit into The digital signal is transmitted to the DSP; the drain of the MOSFET circuit is connected to the D/A converter through the voltage conversion circuit, and the D/A converter is transmitted to the DSP; the DSP is interconnected with the PC.

If the drain-source voltage value of the MOSFET circuit measured by the DSP is within the range of +12V±1V, then the load capacity of the interface of the ammeter communication module meets the requirements.

If the drain-source voltage value of the MOSFET circuit measured by the DSP is not within the range of +12V±1V, the load capacity of the interface of the communication module of the electric meter does not meet the requirements.

The working principle of the utility model is that a single-phase carrier smart meter communication module interface load capacity tester of the utility model detects the drain current and the drain-source voltage of the MOSFET circuit. , The current signal is analyzed and processed, and the resistance value is calculated according to the obtained drain current and drain-source voltage of the MOSFET circuit. After comparing with the initial set value, a negative feedback voltage is output to obtain a resistance whose accuracy meets the measurement requirements. value. The negative feedback voltage signal output by the DSP is connected to the input terminal of the voltage control circuit through the D/A converter; the output terminal of the voltage control circuit is connected to the gate of the MOSFET circuit; the DSP communicates with the PC through the communication interface, and the The measured results are transferred to the PC and saved.

Compared with the prior art, the beneficial effect of the utility model is that the utility model controls the gate-source of the MOSFET circuit through the DSP and the voltage control circuit on the basis of detecting the drain current and the drain-source voltage of the MOSFET circuit voltage to obtain a load whose resistance and accuracy meet the measurement requirements. Finally, through the DSP, the voltage value between the power supply Vcc terminal and the ground of the power supply for the communication module provided by the interface of the ammeter module is obtained, and the automatic detection of the load capacity of the interface of the communication module of the single-phase carrier smart ammeter is realized.

The utility model is suitable for testing the load capacity of the interface of the single-phase carrier intelligent electric meter communication module.

Description of drawings

Figure 1 is a schematic diagram of the main circuit structure of the utility model;

Fig. 2 is a flow chart of detecting the loading capacity of the communication interface of the single-phase carrier smart ammeter according to the present invention.

detailed description

The utility model will be described in detail below in conjunction with the embodiments and with reference to the accompanying drawings.

Fig. 1 is a schematic diagram of the structure of the main circuit of the utility model.

In this embodiment, a single-phase carrier smart meter communication module interface loading capacity tester includes: voltage control circuit, D/A converter, DSP, MOSFET circuit, current detection unit, voltage detection unit, single-phase power supply, A/D Converter, PC, resistor R1 and resistor R2.

The single-phase power supply in the instrument provides power supply for the meter under test, and is connected to the voltage terminal of the meter under test during detection. Resistor R1 and resistor R2 are connected in series between the power supply V _CC terminal and the ground of the module interface to supply power to the module. The voltage detection unit detects the voltage at both ends of the resistor R2, and converts the detected voltage waveform into a digital signal through the A/D converter. It is transmitted to the DSP, and the DSP obtains the drain-source voltage of the MOSFET circuit through the voltage value and the resistance values of the resistor R1 and the resistor R2. The source of the MOSFET circuit is connected to the ground of the interface of the meter module through the current detection unit, and the drain current of the MOSFET circuit of the current detection circuit unit is converted into a digital signal by the A/D converter and transmitted to the DSP. DSP obtains the equivalent resistance value of the circuit between V _CC and the ground terminal at this time according to the obtained drain-source voltage, drain current, resistance value of resistor R1 and resistor R2, which is the same as the initial resistance value in DSP Set the resistance value comparison to form a negative feedback voltage in the form of a digital signal, and control the gate-source voltage of the MOSFET through the D/A converter and the voltage control circuit until the resistance value calculated by the DSP is consistent with the initial setting The values are equal to 96Ω (accuracy meets ±5%). The drain-source voltage of the MOSFET circuit measured under this condition is the voltage between the V _CC terminal of the module interface in the meter and the ground.

According to relevant standard requirements: V _CC voltage should be in the range of +12V±1V, and the load current should be in the range of 0mA～125mA. Therefore, when the drain-source voltage value of the MOSFET circuit measured by the DSP is within the range of +12V±1V, the load capacity of the interface of the ammeter communication module meets the requirements; when the drain-source voltage value of the MOSFET circuit measured by the DSP is not within + In the range of 12V±1V, the load capacity of the communication module interface of the meter does not meet the requirements. The DSP is connected with the PC through the communication interface, and transmits the measured data to the PC and saves it, which is convenient for the recording of the detection data. The initial setting value can be transmitted to DSP through PC.

Fig. 2 is a flow chart of detecting the load capacity of the communication interface of the single-phase carrier smart ammeter of the present invention.

The steps to detect the load capacity of the single-phase carrier smart meter communication interface are as follows:

Step 1: Turn on the single-phase power supply and start the test;

Step 2: Set the initial resistance value of 96Ω through the PC;

Step 3: the current detection unit detects the drain current of the MOSFET circuit;

Step 4: The voltage detection unit detects the voltage value at both ends of R2;

Step 5: DSP obtains the drain current and the drain-source voltage of the MOSFET circuit;

Step 6: Calculate the resistance R of the equivalent resistance between Vcc and ground;

Step 7: The DSP outputs a negative feedback voltage to control the gate-source voltage of the MOSFET circuit;

Step 8: Repeat steps 3 to 7 until the resistance value of the equivalent resistance between Vcc and ground calculated by the DSP meets the measurement requirements, the resistance value is 96Ω, and the accuracy meets ±5%;

Step 9: DSP records the drain-source voltage of the MOSFET circuit at this time, and transmits it to the PC;

Step 10: The test is over.

Through the utility model of a single-phase carrier smart meter communication module interface load capacity tester, the automatic detection of the single-phase carrier smart meter communication module interface load capacity can be realized.

The unexplained parts involved in the utility model are the same as the prior art or implemented by adopting the prior art.

Claims (1)

1. a single-phase carrier intelligent electric meter communication module interface load capacity tester, it is characterized in that, described tester includes voltage control circuit, D/A converter, DSP, MOSFET circuit, current detecting unit, voltage detection unit, single phase poaer supply, A/D converter, PC, resistance R1 and resistance R2；

Described single phase poaer supply connects tested ammeter, provides power supply to tested ammeter；Described resistance R1 and resistance R2 series connection, is attempted by the power supply V that ammeter module interface is powered to communication module_CCAnd between ground；The input of described voltage detection unit is connected on the two ends of resistance R2；The outfan of described voltage detection unit, through A/D converter, converts the analogue signal of detection voltage to digital signal, and is transferred to DSP；The drain electrode of described MOSFET circuit meets the V of ammeter inner module interface_CCEnd, its source electrode connects the ground of ammeter module interface by current detecting unit；The drain current of described current detecting unit detection MOSFET circuit, its outfan, through A/D converter, converts the grid current analogue signal of the MOSFET circuit detected to digital signal, and is transferred to DSP；The drain electrode of described MOSFET circuit connects D/A converter by voltage conversion circuit, D/A converter be transferred to DSP；Described DSP and PC interconnection..