Communication module circuit of single-phase intelligent electric meter and intelligent electric meter

Abstract

The invention belongs to the technical field of intelligent electric meters, and relates to a communication module circuit of a single-phase intelligent electric meter and an intelligent electric meter, an RXD pin of the single-phase intelligent electric meter is connected with an MCU chip, the communication module circuit comprises a first resistor and a diode, the first end of the first resistor is connected with the RXD pin, the second end of the first resistor is connected with the cathode of the diode, and the second end of the first resistor is connected with the anode of the diode. When the single-phase intelligent electric meter is a 09 protocol electric meter, the anode of the diode is connected with a VDD pin of the electric meter and is conducted based on a 5V voltage signal provided by the VDD pin, and when a level signal output by the MCU chip is a high level, the voltage of an RXD pin of the electric meter is pulled up to 5V through the first resistor; when the single-phase intelligent electric meter is a 13-protocol electric meter or a 21-protocol electric meter, the anode of the diode is connected with a reserved pin of the electric meter. The communication module circuit provided by the scheme can be compatible with electric meters with different protocols, and different MCU chips and level conversion circuits do not need to be equipped for the electric meters with different protocols, so that the hardware and later maintenance costs are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of smart electric meters, and in particular to a communication module circuit of a single-phase smart electric meter and a smart electric energy meter. Background Art

[0002] With the development of technology and the increasing requirements for the measurement accuracy and functional diversity of electric energy meters, smart electric energy meters have gradually replaced mechanical electric energy meters. Since 2009, single-phase smart electric energy meters with protocol 09, smart electric energy meters with protocol 13 and smart electric energy meters with protocol 21 have been released. Since smart electric energy meters with different protocols have different module pin definitions, their internal hardware circuits are also different. At the same time, smart electric energy meters with different protocols may use different communication protocol formats during the communication process, resulting in incompatibility between communication protocols and hardware circuits of smart electric energy meters with different protocols during use.

[0003] In the prior art, the communication protocols of different protocols of electric energy meters are analyzed and converted by embedding protocol conversion software between the electric energy meter and the external device, or the configuration file is modified in the communication management software running inside the electric energy meter to solve the problem of incompatibility of communication protocols when different electric energy meters communicate with external devices. However, there is no research on the problem of hardware circuit incompatibility in the prior art. Since the RXD pin of the 09 protocol electric energy meter must work normally at the 5V TTL level, and the RXD pin of the 13 protocol electric energy meter and the 21 protocol electric energy meter can usually work normally at the 3.3V TTL level or 2.5V TTL level, in order to meet the communication requirements of electric energy meters with different protocols, electric energy meters with different protocols need to be equipped with different MCU chips and level conversion circuits to provide level signals for the RXD pin of the electric energy meter, which not only increases the hardware cost when the electric energy meter is used, but also requires multiple sets of hardware to be prepared for later maintenance and on-site operation and maintenance, increasing the investment of human and material resources.

[0004] In summary, it is necessary to design a communication module circuit that is compatible with all current protocol electric energy meters, so as to reduce the hardware adaptation complexity and cost increase caused by protocol differences. Summary of the invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the problem of hardware circuit incompatibility caused by protocol differences of electric energy meters with different protocols in the prior art.

[0006] In order to solve the above technical problems, the present invention provides a communication module circuit of a single-phase smart meter, wherein the RXD pin of the single-phase smart meter is connected to the MCU chip, and the communication module circuit comprises: A first resistor, a first end of which is connected to the RXD pin of the single-phase smart meter; A diode, whose cathode is connected to the second end of the first resistor, and when the single-phase smart meter is a 09 protocol meter, its anode is connected to the VDD pin of the single-phase smart meter, and is turned on based on the 5V voltage signal provided by the VDD pin, and when the level signal output by the MCU chip is a high level, the voltage of the RXD pin of the single-phase smart meter is pulled up to 5V through the first resistor; when the single-phase smart meter is a 13 protocol meter or a 21 protocol meter, its anode is connected to the reserved pin of the single-phase smart meter.

[0007] Preferably, the resistance of the first resistor is .

[0008] Preferably, the resistance of the first resistor is .

[0009] Preferably, it also includes: A second resistor, one end of which is connected to the output end of the MCU chip, and the other end of which is connected to the RXD pin of the single-phase smart meter, is used to divide the voltage and limit the current of the level signal output by the MCU chip.

[0010] Preferably, the resistance of the second resistor is .

[0011] Preferably, the resistance of the second resistor is .

[0012] Preferably, when the single-phase smart meter is a 13-protocol meter or a 21-protocol meter, and the reserved pin of the single-phase smart meter is grounded or suspended, the diode is reversely cut off, and when the level signal provided by the MCU chip is a high level, a voltage signal is provided for the RXD pin of the single-phase smart meter.

[0013] Preferably, when the single-phase smart meter is a 13-protocol meter or a 21-protocol meter, and the reserved pin of the single-phase smart meter is connected to a high-level signal, the diode is turned on based on the voltage signal provided by the reserved pin, and when the level signal provided by the MCU chip is a high level, a voltage signal is provided to the RXD pin of the single-phase smart meter through the first resistor.

[0014] Preferably, the diode is a Schottky diode.

[0015] The present invention also provides a smart electric energy meter, which is connected to the communication module circuit of the above-mentioned single-phase smart electric energy meter.

[0016] The communication module circuit of the single-phase smart meter provided by the present invention has the following beneficial effects: Since the VDD pin of the 09 protocol meter can provide a 5V voltage, and the RXD pin requires a 5V communication level when working, the anode of the diode is connected to the VDD pin of the 09 protocol meter, the cathode of the diode is connected to one end of the first resistor, and the other end of the first resistor is connected to the RXD pin of the meter, so that a diode anti-reverse circuit is designed between the VDD pin and the RXD pin of the 09 protocol meter. The diode is turned on based on the 5V voltage signal provided by the VDD pin, so that when the MCU chip outputs a high-level signal, the RXD can be turned on by using the first resistor. The voltage of the pin is pulled up to 5V, so that the RXD pin works normally; however, the 13-protocol meter or the 21-protocol meter does not clearly stipulate the communication level of the RXD pin, so the anode of the diode is connected to the reserved pin of the meter. When the reserved pin is grounded or suspended, the diode is not turned on, and the RXD pin of the meter can work directly based on the high-level signal output by the MCU chip. When the reserved pin is connected to a high level, the diode is turned on, and when the MCU chip outputs a high-level signal, the voltage of the RXD pin can be pulled up by the first resistor, so that the RXD pin works normally. Only by designing a diode anti-reverse circuit, it is possible to be compatible with the communication requirements of meters with different protocols. There is no need to equip meters with different protocols with different MCU chips, nor is there a need to configure different input and output interface settings and level conversion circuits for different MCU chips, which not only reduces hardware costs, but also facilitates later maintenance and on-site operation and maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein: Figure 1 Schematic diagram of the circuit interface pins of the 09 protocol electric meter and the communication module provided for this application; Figure 2 Schematic diagram of the interface pins of the 13-protocol electric meter and the 21-protocol electric meter and the communication module circuit provided in this application; Figure 3 A schematic diagram of the communication module circuit principle of the single-phase smart meter provided in this application; Figure 4 A schematic diagram of the connection relationship between the communication module circuit of the single-phase smart meter provided in this application and the 09 protocol meter; Figure 5 A schematic diagram of the connection relationship between the communication module circuit of the single-phase smart meter provided in this application and the 13-protocol meter / 21-protocol meter; Description of the accompanying drawings in the specification: 100, single-phase smart meter; 200, MCU chip; 300, first resistor; 400, diode; 500, second resistor. DETAILED DESCRIPTION

[0018] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0019] like Figure 1 The figure shows the pin diagram of the circuit interface between the 09 protocol electric meter and the communication module, where number 9 is a reserved pin (RESERVE), number 10 is a status output pin (EVENOUT), number 11 is a communication status pin (STA), number 12 is a reset pin (RST), number 13 is a signal sending pin (RXD) for the electric meter by the communication module, number 14 is a module setting enable pin (SET), number 15 is a 5V power supply pin (VDD), number 16 is a communication signal output pin (TXD), number 17 and number 18 are communication ground pins (VSS), number 19 and number 20 are analog power pins (VCC), and the RXD pin needs to work at a 5V TTL level.

[0020] like Figure 2 The figure shows the circuit interface pin diagram of the 13-protocol meter and the 21-protocol meter and the communication module, where No. 1 and No. 2 are analog power pins (VCC), No. 3 and No. 4 are communication ground pins (VSS), No. 5 is the communication module sending signal pin (RXD) for the meter, No. 6 is a reserved pin (RESERVE), No. 7 is the module setting enable pin (SET), No. 8 is the communication signal output pin (TXD), No. 9 is the reset pin (RST), No. 10 is the communication status pin (STA), No. 11 is the status output pin (EVENOUT), and No. 12 is a reserved pin (RESERVE). The RXD pin can work at 3.3V or 2.5V TTL level.

[0021] Since the RXD pins of the 09 protocol meters, 13 protocol meters, and 21 protocol meters have different requirements for TTL levels, different MCU chips and level conversion circuits need to be used to meet the working requirements of different protocol meters. Multiple sets of hardware also need to be prepared for later maintenance and on-site operation and maintenance, which increases the investment of manpower and material resources. Based on this, this application designs a communication module circuit that is compatible with 09 protocol meters, 13 protocol meters, and 21 protocol meters, so that different protocol meters can work with only one set of hardware circuits. It is worth noting that since the three-phase communication module of the 09 protocol electric energy meter is different from the communication pins of the 13 protocol electric energy meter and the 21 protocol electric energy meter, they are not compatible. Therefore, this application only addresses the compatibility issue of the communication module of the single-phase electric energy meter.

[0022] See also Figure 3 , Figure 3The figure shows a schematic diagram of a communication module circuit of a single-phase smart meter provided in the present application. The communication module circuit of the single-phase smart meter is applied to a single-phase smart meter 100. The RXD pin of the single-phase smart meter 100 is connected to the MCU chip 200. The communication module circuit of the single-phase smart meter specifically includes a first resistor 300 and a diode 400.

[0023] A first end of the first resistor 300 is connected to the RXD pin of the single-phase smart meter 100 , and a second end of the first resistor 300 is connected to the cathode of the diode 400 .

[0024] Since the pins of the 09 protocol meter are different from those of the 13 protocol meter and the 21 protocol meter, when the communication module circuit compatible with different protocol meters is used for single-phase smart meters of different protocols, the connection relationship between the diode 400 and the single-phase smart meter 100 is also different.

[0025] Specifically, Figure 4 As shown, when the single-phase smart meter 100 is a 09 protocol meter, the anode of the diode 400 is connected to the VDD pin of the single-phase smart meter 100, and the 5V voltage signal provided by the VDD pin of the single-phase smart meter 100 is turned on, and when the level signal output by the MCU chip 200 is high level, the voltage of the RXD pin of the single-phase smart meter 100 is pulled up to 5V through the first resistor 300. By utilizing the characteristic that the VDD pin of the 09 protocol meter can provide a 5V power supply, a diode anti-reverse circuit is set between the VDD pin and the RXD pin. As long as the MCU chip 200 outputs a high level signal, the level of the RXD pin can be pulled up to 5V by using the first resistor 300 and the diode 400, thereby meeting the working requirements of the 09 protocol meter.

[0026] like Figure 5 As shown, when the single-phase smart meter 100 is a 13-protocol meter or a 21-protocol meter, the anode of the diode 400 is connected to a reserved pin of the single-phase smart meter 100 .

[0027] Furthermore, according to the design of each meter manufacturer, the reserved pins of the 13-protocol meter and the 21-protocol meter may be left floating, grounded, or connected to a high-level signal. When the reserved pin of the single-phase smart meter 100 is left floating or grounded, the diode 400 is in a reverse cut-off state. When the level signal provided by the MCU chip 200 is a high level, a voltage signal is provided to the RXD pin of the single-phase smart meter 100, so that the serial port circuit works independently, and the diode anti-reverse circuit has no effect on the serial port.

[0028] When the reserved pin of the single-phase smart meter 100 is connected to a high-level signal, the diode 400 is turned on based on the voltage signal provided by the reserved pin of the single-phase smart meter 100, and when the level signal provided by the MCU chip 200 is a high level, a voltage signal is provided to the RXD pin of the single-phase smart meter 100 through the first resistor 300, which can also meet the working requirements of a 13-protocol meter or a 21-protocol meter.

[0029] Further, in some embodiments of the present application, the diode 400 is a Schottky diode. In the embodiments of the present application, by using a Schottky diode, the forward voltage drop can be much lower than other types of diodes. The low forward voltage drop means that the power consumed on the diode is small, the heat generated is small, and the circuit failure caused by the heating of the diode is reduced; at the same time, the Schottky diode also has the characteristic of fast recovery, and its reverse recovery time is usually at the nanometer level, so that it can quickly recover from the reverse cut-off state to the forward conduction state, reduce the reverse current spikes and voltage vibrations that may be generated during the reverse recovery process, reduce the damage to other components in the circuit, and improve the stability and reliability of the circuit. For example, the model of the diode in the embodiment of the present application can be RB521, which is a Schottky diode, and its forward voltage drop VF is typically 350mV, which is much lower than other types of diodes (such as the forward voltage drop of a silicon diode is about 0.6V~0.7V); at the same time, the RB521 model diode also has a fast recovery characteristic, and its reverse recovery time is less than 500ns.

[0030] Furthermore, the resistance range of the first resistor 300 is , so that it can be compatible with the internal input circuits of meters with different protocols, provide sufficient driving current for the single-phase smart meter 100, and effectively reduce the interference of high-frequency noise on the signal line to the signal. For example, the resistance value of the first resistor 300 can be , , , , or .

[0031] Preferably, in a specific embodiment of the present application, the resistance of the first resistor 300 is , when the resistance of the first resistor 300 is When the RXD pin is in operation, the level of the RXD pin can be pulled up to a stable high level state, and sufficient current can be provided to the single-phase smart meter 100 while effectively reducing power consumption, thereby ensuring the normal operation of the single-phase smart meter 100; in addition, The resistance value can be well compatible with various types of MCU chips 200, adapt to the electrical characteristics of different single-phase smart meters 100 and MCU chips 200, and reduce circuit failures caused by inappropriate resistance values.

[0032] Further, in some embodiments of the present application, Figure 3 As shown, the communication module circuit of the single-phase smart meter also includes a second resistor 500 .

[0033] One end of the second resistor 500 is connected to the MCU chip, and the other end is connected to the RXD pin of the single-phase smart meter 100, and is used to divide the voltage and limit the current of the level signal output by the MCU chip 200, so as to protect the circuit.

[0034] Specifically, since a large current may be generated when the level signal output by the MCU chip 200 changes, the second resistor 500 is used to limit the current, thereby preventing excessive current from damaging the RXD pin of the single-phase smart meter 100. In addition, when the level signal output by the MCU chip 200 does not completely match the level signal required by the RXD pin of the meter 100, the second resistor 500 can divide the level signal and increase it with the first resistor 400, so that the level signal input to the RXD pin of the single-phase smart meter 100 meets the requirements of the single-phase smart meter 100.

[0035] Furthermore, the resistance of the second resistor 500 is If the resistance of the second resistor 500 is too small, when the voltage of the level signal output by the MCU chip 200 fluctuates or the signal changes rapidly, the current cannot be effectively limited. If the resistance of the second resistor 500 is too large, the current required for normal signal transmission will be limited, which may cause the RXD pin of the single-phase smart meter 100 to be unable to correctly identify the signal. Therefore, the present application limits the resistance of the second resistor 500, so that the current can be limited to a safe range under a certain voltage change, while providing sufficient current for signal transmission. For example, the resistance of the second resistor 500 can be , , , , , , , , or .

[0036] Preferably, in a specific embodiment of the present application, the resistance of the second resistor 500 is , which can not only limit the current size, but also respond more quickly when the current changes, and limit the current limit increase in time. In addition, The resistance has a weak attenuation effect on the signal, which can ensure that the signal is transmitted to the RXD pin of the single-phase smart meter 100 with a strong amplitude, ensuring the integrity and accuracy of the signal. At the same time, the resistor with a smaller resistance value is usually smaller in size, which is conducive to the miniaturization and integrated design of the circuit.

[0037] It is worth noting that the communication module circuit of the single-phase smart meter and the other pin connection parts of the meter are the same as those in the prior art. The present application can be compatible with the communication requirements of meters with different protocols by only adding a diode anti-reverse circuit. There is no need to equip meters with different protocols with different MCU chips, nor is there a need to configure different input and output interface settings and level conversion circuits for different MCU chips. This not only reduces hardware costs, but also facilitates later maintenance and on-site operation.

[0038] Based on the communication module circuit of the single-phase smart meter provided in the above embodiment, the embodiment of the present application further provides a smart electric energy meter, which is connected to the communication module circuit of the single-phase smart meter.

[0039] Optionally, the communication module circuit can be integrated inside the smart power meter, or can be arranged outside the smart power meter and directly connected to the smart power meter.

[0040] When the communication module circuit is integrated inside the smart electricity meter, the shell of the smart electricity meter can provide a certain shielding effect for the communication module circuit, reduce the interference of external signals on the communication module circuit, ensure communication stability, and make the connection between the communication module circuit and other components of the smart electricity meter more stable, avoiding poor contact problems due to vibration, dust and other factors.

[0041] When the communication module circuit is external, it is more conducive to fault isolation of the communication module circuit. By detecting and repairing the communication circuit module, it is possible to quickly determine whether the fault is located in the smart energy meter body or the communication module circuit, thereby simplifying maintenance and repair costs.

[0042] Obviously, the above embodiments are merely examples for the purpose of clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A communication module circuit of a single-phase smart meter, characterized in that: The RXD pin of the single-phase smart meter is connected to the MCU chip, and the communication module circuit includes: A first resistor, a first end of which is connected to the RXD pin of the single-phase smart meter; A diode, whose cathode is connected to the second end of the first resistor, and when the single-phase smart meter is a 09 protocol meter, its anode is connected to the VDD pin of the single-phase smart meter, and is turned on based on the 5V voltage signal provided by the VDD pin, and when the level signal output by the MCU chip is a high level, the voltage of the RXD pin of the single-phase smart meter is pulled up to 5V through the first resistor; when the single-phase smart meter is a 13 protocol meter or a 21 protocol meter, its anode is connected to the reserved pin of the single-phase smart meter.

2. The communication module circuit of the single-phase smart meter according to claim 1, characterized in that: The resistance of the first resistor is .

3. The communication module circuit of the single-phase smart meter according to claim 2, characterized in that: The resistance of the first resistor is .

4. The communication module circuit of the single-phase smart meter according to claim 1, characterized in that: Also includes: A second resistor, one end of which is connected to the output end of the MCU chip, and the other end of which is connected to the RXD pin of the single-phase smart meter, is used to divide the voltage and limit the current of the level signal output by the MCU chip.

5. The communication module circuit of the single-phase smart meter according to claim 4, characterized in that: The resistance of the second resistor is .

6. The communication module circuit of the single-phase smart meter according to claim 5, characterized in that: The resistance of the second resistor is .

7. The communication module circuit of the single-phase smart meter according to claim 1, characterized in that: When the single-phase smart meter is a 13-protocol meter or a 21-protocol meter, and the reserved pin of the single-phase smart meter is grounded or suspended, the diode is reversely cut off, and when the level signal provided by the MCU chip is a high level, a voltage signal is provided for the RXD pin of the single-phase smart meter.

8. The communication module circuit of the single-phase smart meter according to claim 1, characterized in that: When the single-phase smart meter is a 13-protocol meter or a 21-protocol meter, and the reserved pin of the single-phase smart meter is connected to a high-level signal, the diode is turned on based on the voltage signal provided by the reserved pin, and when the level signal provided by the MCU chip is a high level, a voltage signal is provided to the RXD pin of the single-phase smart meter through the first resistor.

9. The communication module circuit of the single-phase smart meter according to claim 1, characterized in that: The diode is a Schottky diode.

10. A smart electric energy meter, characterized in that: The smart electric energy meter is connected to the communication module circuit of the single-phase smart electric energy meter as described in any one of claims 1 to 9.

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