Ammeter collector

Abstract

The utility model discloses an electricity meter collector, which relates to the field of power electronics and is characterized in that the electricity meter collector receives isolation voltage provided by an electricity meter through an electricity meter external interface and converts the isolation voltage into voltage required by an electricity meter signal transmission circuit and a network serial port unvarnished transmission chip to work through a DCDC power supply conversion circuit; a power supply mode of converting alternating current into direct current is not needed, the problems of surge and isolation of alternating current power supply do not need to be worried about, and the safety of the scheme is improved; a battery power supply mode is not needed, the maintenance is simple, and the cost of the scheme is reduced; in addition, due to the network port structure of the external interface of the electricity meter, the electricity meter collector and the electricity meter are more convenient to plug and unplug; and secondly, the remote communication between the ammeter collector and the master station adopts an Ethernet communication mode, the cost of a network serial port unvarnished transmission chip is low, and the function of bidirectional data unvarnished transmission can be completed without developing a software protocol stack, so that the development workload of the software protocol stack is greatly saved.

Description

Technical Field

[0001] This utility model relates to the field of power electronics, and in particular to an electricity meter data collector. Background Technology

[0002] The most common power supply method for electricity meter data collectors is AC-to-DC conversion, which involves using a transformer or switching power supply to convert mains power into low-voltage DC before powering the data collector. A very small number use batteries. However, if an AC-to-DC power supply is used, surge protection and isolation issues must be considered. This means preventing damage to the high-voltage circuitry of the data collector in the event of AC surges, ensuring the safety of the data collector during installation and for personnel who may accidentally touch it. Furthermore, battery power is generally used in environments without mains power. However, due to limitations in battery life and maintenance, prolonged battery use for powering the data collector can result in significant cost waste.

[0003] Remote communication between the data collector and the master station typically uses Ethernet. Data collectors generally implement Ethernet communication using two main approaches: one is using an Ethernet hardware protocol stack chip such as the W5500 (SPI interface (Serial Peripheral Interface)) + a standard MCU (Microcontroller Unit); the other is using an MCU (with built-in MAC (Media Access Control)) + a PHY chip. While the Ethernet hardware protocol stack chip simplifies software operations, its high hardware cost makes the Ethernet hardware stack chip + standard MCU solution significantly more expensive than the MCU (with built-in MAC) + PHY (Physical Layer) solution, thus reducing product competitiveness. The MCU (with built-in MAC) + PHY chip solution, while relatively cheaper, requires the development of a software protocol stack, which has a longer development cycle. Utility Model Content

[0004] The purpose of this invention is to provide an electricity meter data acquisition device. This device receives the isolation voltage provided by the electricity meter through an external interface, eliminating the need for AC-to-DC power conversion and mitigating the surge and isolation issues associated with AC power, thus improving safety. It also eliminates the need for battery power, simplifying maintenance. Compared to traditional AC-to-DC and battery-powered devices, it eliminates the cost of rectifier circuits or batteries, reduces the size of the device, and facilitates on-site installation. Furthermore, the external interface structure makes plugging and unplugging between the device and the meter easier. Secondly, the remote communication between the device and the main station uses Ethernet communication. The low cost of the network serial port pass-through chip and the fact that bidirectional data transmission can be achieved without developing a software protocol stack significantly reduce the workload of software protocol stack development.

[0005] To solve the above-mentioned technical problems, this utility model provides an electricity meter data acquisition device, including: a network serial port transparent transmission chip, a DC-DC power conversion circuit, an electricity meter signal transmission circuit, an external electricity meter interface in the shape of a network port, and an Ethernet interface;

[0006] The external interface of the electricity meter is connected to the network serial port transparent transmission chip through the electricity meter signal transmission circuit. The external interface of the electricity meter is connected to the electricity meter for mutual communication between the network serial port transparent transmission chip and the electricity meter.

[0007] The input terminal of the DC-DC power conversion circuit is connected to the voltage output terminal of the meter through the external interface of the meter. The first output terminal is connected to the power supply terminal of the meter signal transmission circuit. The second output terminal is connected to the first power supply terminal of the network serial port pass-through chip. The third output terminal is connected to the second power supply terminal of the network serial port pass-through chip. This circuit is used to convert the isolation voltage transmitted by the meter into the first voltage required for the operation of the meter signal transmission circuit and the second and third voltages required for the operation of the network serial port pass-through chip.

[0008] The Ethernet signal receiving port and the Ethernet signal transmitting port of the network serial port pass-through chip are both connected to the Ethernet cable through the Ethernet interface.

[0009] Optionally, the meter signal transmission circuit includes: an RS485 chip, a first resistor, a second resistor, and a third resistor;

[0010] The RS485 chip's receive data output pin is connected to the serial data receive pin of the network serial port pass-through chip, and its drive data input pin is connected to the serial data transmit pin of the network serial port pass-through chip. Both the receive enable pin and the drive enable pin are connected to the RS485 transmit / receive switching control pin of the network serial port pass-through chip. The positive differential signal terminal of the RS485 chip is connected to the first terminal of the first resistor, the first terminal of the second resistor, and the positive differential signal terminal of the external interface of the meter, respectively. The negative differential signal terminal of the RS485 chip is connected to the second terminal of the second resistor, the first terminal of the third resistor, and the negative differential signal terminal of the external interface of the meter, respectively.

[0011] The second end of the first resistor is connected to the first output end of the DC-DC power conversion circuit;

[0012] The second end of the third resistor is connected to ground.

[0013] Optional, also includes:

[0014] A passive crystal circuit is connected to the clock signal terminal of the network serial port pass-through chip to provide a preset clock signal to the network serial port pass-through chip.

[0015] Optionally, the passive crystal circuit includes: a passive crystal, a first load capacitor, and a second load capacitor;

[0016] The external crystal oscillator input terminal of the passive crystal is connected to the positive phase input terminal of the crystal oscillation of the clock signal of the network serial port pass-through chip and the first terminal of the first load capacitor, respectively. The external crystal oscillator output terminal is connected to the inverted phase output terminal of the crystal oscillation of the clock signal of the network serial port pass-through chip and the first terminal of the second load capacitor, respectively.

[0017] The second terminal of both the first load capacitor and the second load capacitor is grounded.

[0018] Optional, also includes:

[0019] The LED circuit has its first end connected to the fourth output terminal of the DC-DC power conversion circuit, and its second end connected to the Ethernet communication connection indicator driver pin, PHY chip connection indicator driver pin, and TCP client mode indicator driver pin of the network serial port pass-through chip, respectively. The LED is used to light up when the network serial port pass-through chip is powered on and has a normal Ethernet communication connection, when the PHY chip inside the network serial port pass-through chip is working normally, and when the network serial port pass-through chip is in TCP client mode.

[0020] Optionally, the Ethernet interface is an RJ45 interface, and the electricity meter data collector further includes:

[0021] The network transformer circuit has a first Ethernet signal receiving port connected to the Ethernet signal transmitting port of the network serial port pass-through chip, a first Ethernet signal receiving and transmitting port connected to the Ethernet signal receiving port of the network serial port pass-through chip, and a second Ethernet signal receiving port and a second Ethernet signal receiving and transmitting port both connected to the Ethernet cable through the RJ45 interface.

[0022] Optionally, the network transformer circuit is a network voltage regulator chip. The primary side center tap CT pin of the network voltage regulator chip is connected to a preset power supply and a ground wire, respectively. The secondary side center tap CT pin is connected to the preset power supply and the ground wire, respectively. The first Ethernet signal receiving port is connected to the Ethernet signal transmitting port of the network serial port pass-through chip. The first Ethernet signal receiving and transmitting port is connected to the Ethernet signal receiving port of the network serial port pass-through chip. The second Ethernet signal receiving port and the second Ethernet signal receiving and transmitting port are both connected to the Ethernet cable through the RJ45 interface.

[0023] Optionally, the network transformer circuit further includes: a ferrite bead, a first capacitor, and a second capacitor;

[0024] The first end of the magnetic bead is connected to the preset power supply, and the second end is connected to the first end of the first capacitor, the first end of the second capacitor, the CT pin of the primary side of the network voltage regulator chip, and the CT pin of the secondary side of the network voltage regulator chip, respectively.

[0025] The second terminal of the first capacitor is grounded;

[0026] The second terminal of the second capacitor is grounded.

[0027] Optionally, the network transformer circuit further includes: a first current-limiting resistor, a second current-limiting resistor, a third current-limiting resistor, a fourth current-limiting resistor, a first ESD transistor, a second ESD transistor, a third ESD transistor, and a fourth ESD transistor.

[0028] The first end of the first current-limiting resistor is connected to the serial data positive input port of the network voltage regulator chip, and the second end is connected to the first end of the first ESD transistor.

[0029] The first end of the second current-limiting resistor is connected to the serial data negative input port of the network voltage regulator chip, and the second end is connected to the first end of the second ESD transistor;

[0030] The first end of the third current-limiting resistor is connected to the serial data positive receiving port of the network voltage regulator chip, and the second end is connected to the first end of the third ESD transistor.

[0031] The first end of the fourth current-limiting resistor is connected to the serial data negative receiving port of the network voltage regulator chip, and the second end is connected to the first end of the fourth ESD transistor.

[0032] The second ends of the first ESD transistor, the second ends of the second ESD transistor, the second ends of the third ESD transistor, and the second ends of the fourth ESD transistor are all grounded.

[0033] Optionally, the Ethernet interface is an RJ45 interface, and the electricity meter data collector further includes:

[0034] The Bob Smith circuit has its first Ethernet signal receiving port connected to the Ethernet signal transmitting port of the network serial port pass-through chip, and its first Ethernet signal receiving and transmitting port connected to the Ethernet signal receiving port of the network serial port pass-through chip. Both the second Ethernet signal receiving port and the second Ethernet signal receiving and transmitting port are connected to the Ethernet cable through the RJ45 interface.

[0035] The purpose of this invention is to provide an electricity meter data acquisition device. This device receives the isolation voltage provided by the electricity meter through an external interface and converts it into the voltage required for the meter signal transmission circuit and the network serial port pass-through chip via a DC-DC power conversion circuit. This eliminates the need for AC-to-DC power supply, avoiding the surge and isolation issues associated with AC power, thus improving the safety of the solution. It also eliminates the need for battery power, simplifying maintenance. Compared to traditional AC-to-DC and battery power supplies, it eliminates the cost of rectifier circuits or batteries, reduces the size of the data acquisition device, and facilitates on-site installation. Furthermore, the external interface structure makes plugging and unplugging between the data acquisition device and the electricity meter easier. Secondly, the remote communication between the data acquisition device and the master station uses Ethernet communication. Because the network serial port pass-through chip is low-cost and can achieve bidirectional data pass-through without the need for software protocol stack development, it significantly reduces the workload of software protocol stack development. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0037] Figure 1 A schematic diagram of the structure of an electricity meter data collector provided by this utility model;

[0038] Figure 2 This utility model provides a schematic diagram of the structure of a power conversion module;

[0039] Figure 3 A schematic diagram of the structure of a meter signal transmission circuit provided by this utility model;

[0040] Figure 4 A schematic diagram of the structure of an external interface for an electricity meter provided by this utility model;

[0041] Figure 5 This is a schematic diagram of the structure of a passive crystal circuit provided by this utility model;

[0042] Figure 6 A schematic diagram of the structure of a debugging interface provided by this utility model;

[0043] Figure 7 A schematic diagram of an LED circuit provided by this utility model;

[0044] Figure 8 A schematic diagram of the structure of an RJ45 interface provided by this utility model;

[0045] Figure 9 A schematic diagram of the pin definition of an RJ45 interface provided by this utility model;

[0046] Figure 10 A schematic diagram of a network transformer circuit provided by this utility model;

[0047] Figure 11 A schematic diagram of a Bob Smith circuit provided by this utility model;

[0048] Figure 12 This is a schematic diagram of another type of electricity meter data collector provided by this utility model. Detailed Implementation

[0049] The core of this utility model is to provide an electricity meter data acquisition device. This device receives the isolation voltage provided by the electricity meter through an external interface, eliminating the need for AC-to-DC power conversion and mitigating the surge and isolation issues associated with AC power, thus improving safety. It also eliminates the need for battery power, simplifying maintenance. Compared to traditional AC-to-DC and battery-powered devices, it eliminates the cost of rectifier circuits or batteries, reducing the device's size and facilitating on-site installation. Furthermore, the external interface's built-in network port structure makes plugging and unplugging between the data acquisition device and the meter easier. Secondly, the remote communication between the data acquisition device and the main station uses Ethernet communication. The low cost of the network serial port pass-through chip and the fact that bidirectional data transmission can be achieved without developing a software protocol stack significantly reduces the workload of software protocol stack development.

[0050] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0051] Please refer to Figure 1 , Figure 1 This utility model provides a structural schematic diagram of an electricity meter data acquisition device. The electricity meter data acquisition device includes: a network serial port transparent transmission chip 1, a power conversion module 2, an electricity meter signal transmission circuit 3, a network port-shaped external electricity meter interface 4, and an Ethernet interface 5;

[0052] The external interface 4 of the electricity meter is connected to the network serial port transparent transmission chip 1 through the electricity meter signal transmission circuit 3. The external interface 4 of the electricity meter is connected to the electricity meter for mutual communication between the network serial port transparent transmission chip 1 and the electricity meter.

[0053] The input terminal of the power conversion module 2 is connected to the voltage output terminal of the meter through the external interface 4 of the meter. The first output terminal is connected to the power supply terminal of the meter signal transmission circuit 3. The second output terminal is connected to the first power supply terminal of the network serial port pass-through chip 1. The third output terminal is connected to the second power supply terminal of the network serial port pass-through chip 1. This module is used to convert the isolation voltage transmitted by the meter into the first voltage required for the operation of the meter signal transmission circuit 3 and the second and third voltages required for the operation of the network serial port pass-through chip 1.

[0054] The Ethernet signal receiving port and the Ethernet signal transmitting port of the network serial port pass-through chip 1 are both connected to the Ethernet cable through the Ethernet interface 5.

[0055] In this invention, considering that electricity meter collectors commonly use AC-to-DC power supply and battery power supply, the AC-to-DC power supply method requires consideration of AC surge and isolation issues, as well as the addition of rectifier devices to prevent damage to the high-voltage circuitry of the electricity meter collector during AC surges, thus increasing the cost of rectifier devices. Furthermore, battery power supply results in significant cost waste due to battery lifespan and maintenance limitations. Therefore, this solution adds an external interface 4 for the electricity meter. The external interface 4 directly connects the electricity meter collector to the meter's voltage output terminal to receive the isolated voltage (DC voltage) provided by the meter. This voltage is then converted by the power conversion module 2 into the voltage required for the operation of the meter signal transmission circuit 3 and the network serial port pass-through chip 1. This eliminates the need for an AC-to-DC power supply and avoids the associated costs. The surge and isolation issues of AC power supply improve the safety of the solution, and the elimination of the need for additional rectifier devices reduces the cost of the solution. It also eliminates the need for battery power, simplifying maintenance. Compared to traditional AC-to-DC power supply and battery power supply for meter collectors, it eliminates the cost of rectifier circuits or batteries, reduces the size of the meter collector, and facilitates on-site installation. Furthermore, the external interface 4 structure of the meter makes plugging and unplugging between the meter collector and the meter easier. Secondly, considering that remote communication between the meter collector and the main station uses Ethernet communication, but existing solutions are either too costly or have long software protocol stack development cycles, this solution chooses a built-in network serial port pass-through chip 1. This leverages the low cost of the network serial port pass-through chip 1 and the fact that it can complete the bidirectional data pass-through function without developing a software protocol stack, greatly saving the development workload of the software protocol stack.

[0056] It should be noted that the power conversion module 2 includes: a DC-DC (Direct Current to Direct Current) converter chip, a first LDO (Low Dropout Regulator) chip, and a second LDO chip, with the following structure: Figure 2 As shown, taking 12V as an example, the 12V isolation voltage transmitted by the electricity meter is input to the DC-DC converter chip through a filter capacitor and a feedback resistor. The output voltage of the DC-DC converter chip can be adjusted by changing the resistance value of the feedback resistor. For example, the DC-DC converter chip outputs 5V to the power supply terminal of the electricity meter signal transmission circuit 3 (RS485 chip) and the first LDO chip. The first LDO chip outputs 3.3V to the first power supply terminal of the network serial port pass-through chip 1. Secondly, the 3.3V voltage is also supplied to the second LDO chip, which outputs 1.8V to the second power supply terminal of the network serial port pass-through chip 1.

[0057] This embodiment provides an electricity meter data acquisition device. The device receives the isolation voltage provided by the electricity meter through the external interface 4 and converts it into the voltage required for the operation of the electricity meter signal transmission circuit 3 and the network serial port pass-through chip 1 via the power conversion module 2. This eliminates the need for AC-to-DC power supply, avoiding surge and isolation issues associated with AC power, thus improving the safety of the solution. It also eliminates the need for battery power, simplifying maintenance. Compared to traditional AC-to-DC and battery power supplies, this eliminates the cost of rectifier circuits or batteries, reduces the size of the data acquisition device, and facilitates on-site installation. Furthermore, the external interface 4 structure makes plugging and unplugging between the data acquisition device and the electricity meter easier. Secondly, the remote communication between the data acquisition device and the master station uses Ethernet communication. Because the network serial port pass-through chip 1 is low-cost and can perform bidirectional data pass-through without the need for software protocol stack development, it significantly reduces the workload of software protocol stack development.

[0058] Based on the above embodiments:

[0059] As an optional embodiment, the meter signal transmission circuit 3 includes: an RS485 chip, a first resistor R1, a second resistor R2, and a third resistor R3;

[0060] The RS485 chip's receive data output pin is connected to the serial data receive pin of the network serial port pass-through chip 1, the drive data input pin is connected to the serial data transmit pin of the network serial port pass-through chip 1, the receive enable pin and the drive enable pin are both connected to the RS485 transmit / receive switching control pin of the network serial port pass-through chip 1, the differential signal positive terminal of the RS485 chip is connected to the first terminal of the first resistor R1, the first terminal of the second resistor R2 and the differential signal positive terminal of the external interface 4 of the meter, respectively, and the differential signal negative terminal of the RS485 chip is connected to the second terminal of the second resistor R2, the first terminal of the third resistor R3 and the differential signal negative terminal of the external interface 4 of the meter, respectively.

[0061] The second terminal of the first resistor R1 is connected to the first output terminal of the power conversion module 2;

[0062] The second terminal of the third resistor R3 is connected to ground.

[0063] In this invention, considering that existing electricity meter collectors still rely on local communication (between the collector and the meter), and that the main local communication technologies are power line communication (PLC) and low-power wireless communication, the following solutions are proposed. If PLC is used, the entire communication process is susceptible to interference from power grid noise, resulting in a low transmission rate. If low-power wireless communication is used, the communication signal is easily affected by obstacles or electromagnetic interference. Therefore, this solution chooses to embed an RS485 chip in the electricity meter collector, using RS485 communication as the local communication method. RS485 communication has advantages such as strong anti-interference, reliable transmission, and low cost, thus significantly reducing interference during transmission. Furthermore, considering that the RS485 chip uses differential signal transmission, i.e., the logic state is represented by the voltage difference between line A (positive phase) and line B (negative phase), even if external interference (such as electromagnetic noise) acts on both lines A and B simultaneously, While common-mode noise is generated, external interference is suppressed because the receiver only detects the voltage difference between the two lines. Furthermore, this solution adds a first resistor R1, a second resistor R2, and a third resistor R3. When the RS485 bus (lines A and B) is idle (no device transmitting), the voltage between lines A and B is stabilized at a defined state (logic "1") through the pull-up resistor – the first resistor R1 (line A to VCC) and the pull-down resistor – the third resistor R3 (line B to GND), preventing false triggering caused by floating signals (such as false triggering due to noise). The second resistor R2 is connected in parallel across the RS485 bus (lines A and B) to ensure impedance matching, eliminating signal reflection and ensuring that the signal is completely absorbed at the end, avoiding waveform distortion caused by reflection.

[0064] It should be noted that, in practical applications, the structure of the meter signal transmission circuit 3 composed of the RS485 chip is as follows: Figure 3As shown, the differential signal lines (A / B lines) pass through two thermistors and two TVS diodes before being input to the RS485 chip. The thermistors are used for temperature monitoring and overheat protection, monitoring the temperature of the bus nodes in real time to prevent communication abnormalities or hardware damage due to excessive node temperature. In long-distance cables, temperature changes can cause impedance changes; impedance matching, i.e., temperature compensation, is achieved by adjusting the terminating resistor to improve Ethernet communication quality and ensure signal stability during transmission. Furthermore, the thermistors are connected in series in the loop; when abnormal current causes a temperature increase, the thermistor's resistance increases to limit the current increase, ensuring loop safety under overcurrent conditions. The terminating resistor (second resistor R2) is added to the 485 port of the meter; no resistor is added to the data acquisition unit. The first resistor R1 and the second resistor R2 are bias resistors, ensuring that the 485 bus is in a defined state (logic 1) when idle, preventing false triggering due to noise. Since the TXD1 and RXD1 of the network serial port pass-through chip 1 are compatible with 3.3V and 5V levels, the receiver output and driver input of the RS485 chip do not need to be level converted. The RS485 chip also adds current-limiting resistors to the TXD1 and RXD1 ports of the network serial port pass-through chip 1 at its own connection port.

[0065] It should also be noted that the electricity meter provides a 12V isolation voltage, GND, and 485A and 485B signals to the meter data acquisition unit through external interface 4. The external interface 4 has a network port shape, so a network cable is simply plugged in for connection; no high-voltage power is required, making installation convenient and safe. The electricity meter contains various pluggable modules. Because the GPRS module involves an antenna, the power supply to the built-in module is isolated from the mains power. Furthermore, the carrier PA chip inside the meter is generally powered by 12V. For compatibility reasons, the module's main power supply is usually 12V (with isolation). Therefore, when connecting this meter data acquisition unit, simply connect the 12V isolation voltage originally supplied to the built-in module to external interface 4; no additional conversion cost is required. The structure of external interface 4 is as follows: Figure 4 As shown, an ESD transistor is connected in series in the grounding terminal of the external interface 4 of the electricity meter to clamp the voltage value of the circuit and ensure that the 12V isolation voltage is stably transmitted to the electricity meter collector.

[0066] As an optional embodiment, it also includes:

[0067] Passive crystal circuit 6 is connected to the clock signal terminal of network serial port transparent transmission chip 1 and is used to provide a preset clock signal to network serial port transparent transmission chip 1.

[0068] In this invention, considering that the network serial port pass-through chip 1 needs to be equipped with a clock source, but if a built-in clock source is selected, it will have disadvantages such as sensitivity to external interference, susceptibility to external ambient temperature, and low stability. Therefore, this solution selects an external passive crystal circuit 6. Among all resonator series, the passive crystal circuit 6 has relatively low cost, high stability, is not sensitive to external interference, and is not easily affected by external ambient temperature, so it can serve as a stable clock source for the network serial port pass-through chip 1.

[0069] As an optional embodiment, the passive crystal circuit 6 includes: a passive crystal, a first load capacitor C10, and a second load capacitor C20;

[0070] The external crystal oscillator input terminal of the passive crystal is connected to the positive phase input terminal of the crystal oscillator of the clock signal of the network serial port transparent transmission chip 1 and the first terminal of the first load capacitor C10, respectively. The external crystal oscillator output terminal is connected to the inverted phase output terminal of the crystal oscillator of the clock signal of the network serial port transparent transmission chip 1 and the first terminal of the second load capacitor C20, respectively.

[0071] The second terminal of the first load capacitor C10 and the second terminal of the second load capacitor C20 are both grounded.

[0072] In this invention, the passive crystal circuit 6 includes a passive crystal, a first load capacitor C10, and a second load capacitor C20. The passive crystal (generally a quartz crystal) is a high-Q resonator whose physical characteristics cause it to vibrate mechanically at a specific frequency, thereby forming a stable electrical resonance. That is, the resonant characteristics of the crystal, together with the external capacitors, form an oscillation circuit to generate a clock signal. Since the passive crystal circuit 6 serves as the clock source for the network serial port pass-through chip 1, the passive crystal, the first load capacitor C10, and the second load capacitor C20, together with the inverting amplifier, feedback resistor, and current-limiting resistor integrated within the network serial port pass-through chip 1, constitute a Pierce oscillation circuit. The passive crystal provides a frequency reference through mechanical resonance, and the first load capacitor C10 and the second load capacitor C20, as load capacitors, work in conjunction with the internal circuitry of the network serial port pass-through chip 1 to ensure accurate oscillation and stable operation of the jointly constructed Pierce oscillation circuit. The capacitance values ​​of the first load capacitor C10 and the second load capacitor C20 are selected according to actual conditions to balance crystal parameters and improve circuit stability.

[0073] It should be noted that the structure of the passive crystal circuit 6 is as follows: Figure 5 As shown, the passive crystal, together with two grounded load capacitors, provides a 30MHz start clock for the network serial port pass-through chip 1. Figure 6As shown, the electricity meter collector can also include a debugging interface for connecting the RESFT terminal and GND of the network serial port transparent transmission chip 1, for restoring the factory settings of the network serial port transparent transmission chip 1, which is active low.

[0074] As an optional embodiment, it also includes:

[0075] LED circuit 7 has its first end connected to the fourth output end of power conversion module 2, and its second end connected to the Ethernet communication connection indicator drive pin, PHY chip connection indicator drive pin, and TCP client mode indicator drive pin of network serial port pass-through chip 1, respectively. It is used to light up when the network serial port pass-through chip 1 is powered on and has a normal Ethernet communication connection, when the PHY chip inside the network serial port pass-through chip 1 is working normally, and when the network serial port pass-through chip 1 is in TCP client mode.

[0076] In this invention, considering that the normal operation of the network serial port pass-through chip 1 is crucial in the actual operation of the electricity meter collector, this solution adds an LED circuit 7. By observing the lighting status of the LED circuit 7, the operating status of the network serial port pass-through chip 1 can be detected in a timely manner. Specifically, the LED circuit 7 can light up when the network serial port pass-through chip 1 is connected to the Ethernet in a normal communication manner after being powered on, when the PHY chip inside the network serial port pass-through chip 1 is working normally after being powered on, and when the network serial port pass-through chip 1 is in TCP (Transmission Control Protocol) client mode after being powered on, so that users or operators can observe the operating status of the network serial port pass-through chip 1 in a timely manner.

[0077] It should be noted that, as Figure 7 As shown, the LED (Light Emitting Diode) circuit 7 can include a first light-emitting diode L1, a second light-emitting diode L2, a third light-emitting diode L3, and corresponding current-limiting resistors. On the one hand, it is used to control the brightness of the first light-emitting diode L1, the second light-emitting diode L2, and the third light-emitting diode L3, and on the other hand, it also controls the current sinking magnitude of the IO port. A low level lights up the corresponding light-emitting diode.

[0078] As an optional embodiment, Ethernet interface 5 is an RJ45 interface, and the electricity meter data collector also includes:

[0079] The network transformer circuit 8 has a first Ethernet signal receiving port connected to the Ethernet signal transmitting port of the network serial port pass-through chip 1. The first Ethernet signal receiving and transmitting port is connected to the Ethernet signal receiving port of the network serial port pass-through chip 1. The second Ethernet signal receiving port and the second Ethernet signal receiving and transmitting port are both connected to the Ethernet cable through an RJ45 interface.

[0080] In this utility model, considering that the electricity meter collector needs to be connected to the Ethernet cable and the main station through the Ethernet interface 5, in order for the electricity meter collector to carry out stable long-distance transmission, this solution chooses to add a network transformer circuit 8. The first advantage is that the network transformer circuit 8 can enhance the signal through signal coupling, thereby improving the signal transmission distance and stability, helping to eliminate signal attenuation during long-distance transmission, and ensuring the correct transmission of data. The second advantage is that because the PHY in the network serial port pass-through chip 1 is directly connected to the Ethernet cable, its output signal will suffer significant loss after reaching a certain distance. Furthermore, if the Ethernet cable is directly connected to the network serial port pass-through chip 1, it is easily susceptible to lightning surges and static electricity, causing damage. The network transformer circuit 8, however, can magnetically isolate the network serial port pass-through chip 1 from the external network (such as the Ethernet cable), cutting off the DC component and ground loop, thus preventing chip damage due to voltage differences or lightning surges. The third advantage is its common-mode noise suppression capability. The differential transmission characteristics of the network transformer circuit 8 can suppress common-mode interference (such as power supply noise and electromagnetic radiation), improving the signal-to-noise ratio. The fourth advantage is level matching, converting the low-voltage differential signal output by the network serial port pass-through chip 1 into an Ethernet level suitable for long-distance transmission, enhancing driving capability. In addition, this solution selects the RJ45 interface as Ethernet interface 5 because the RJ45 interface has a metal shield, which can reduce the radiation of high-frequency signals and reduce the impact of electromagnetic interference on the internal circuit structure of the electricity meter collector. Furthermore, the RJ45 interface is compatible with various network cables to ensure physical interoperability with devices such as switches and routers.

[0081] It should be noted that the structure of the RJ45 interface is as follows: Figure 8 As shown, the RJ45 interface uses a 100Mbps connection, and the pin definitions are as follows. Figure 9 As shown.

[0082] As an optional embodiment, the network transformer circuit 8 is a network voltage regulator chip. The CT pin of the primary side of the network voltage regulator chip is connected to the preset power supply and ground respectively, and the CT pin of the secondary side is connected to the preset power supply and ground respectively. The first Ethernet signal receiving port is connected to the Ethernet signal transmitting port of the network serial port pass-through chip 1, and the first Ethernet signal receiving and transmitting port is connected to the Ethernet signal receiving port of the network serial port pass-through chip 1. The second Ethernet signal receiving port and the second Ethernet signal receiving and transmitting port are both connected to the Ethernet cable through the RJ45 interface.

[0083] In this invention, considering that the PHY in the network serial port pass-through chip 1 may be a voltage-driven PHY or a current-driven PHY, if the PHY is a voltage-driven PHY, then the CT pin of the primary side and the CT pin of the secondary side of the network voltage regulator chip need to be grounded; conversely, if the PHY is a current-driven PHY, then the CT pin of the primary side and the CT pin of the secondary side of the network voltage regulator chip need to be connected to a preset power supply. Therefore, the network transformer circuit 8 of this solution can stably support the network serial port pass-through chip 1 under both types of PHYs.

[0084] As an optional embodiment, the network transformer circuit 8 further includes: a ferrite bead X, a first capacitor C1, and a second capacitor C2;

[0085] The first end of the magnetic bead X is connected to a preset power supply, and the second end is connected to the first end of the first capacitor C1, the first end of the second capacitor C2, the CT pin of the primary side of the network voltage regulator chip, and the CT pin of the secondary side of the network voltage regulator chip, respectively.

[0086] The second terminal of the first capacitor C1 is grounded;

[0087] The second terminal of the second capacitor C2 is grounded.

[0088] In this invention, considering that if the PHY in the network serial port pass-through chip 1 is a current-driven PHY, the CT pin of the primary side and the CT pin of the secondary side of the network voltage regulator chip need to be connected to a preset power supply. Also, considering that the Ethernet signal may be subject to excessive interference during transmission, this solution also adds a ferrite bead X, a first capacitor C1, and a second capacitor C2. The ferrite bead X can effectively suppress high-frequency noise, while the first capacitor C1 and the second capacitor C2 serve as filters to improve the accuracy of the Ethernet signal transmission process.

[0089] It should be noted that in practical applications, when the PHY in the network serial port pass-through chip 1 is a voltage-driven PHY, the CT pin of the primary side and the CT pin of the secondary side of the network voltage regulator chip need to be grounded; conversely, if the PHY in the network serial port pass-through chip 1 is a current-driven PHY, then the CT pin of the primary side and the CT pin of the secondary side of the network voltage regulator chip need to be connected to a preset power supply. Therefore, in order to be compatible with the two types of PHY, this solution can also set corresponding switching devices, such as: first switch, second switch, and third switch. Among them, the first end of the first switch is connected to the preset power supply, the second end is connected to the first end of the magnetic bead X, and the control end is connected to the controller.

[0090] The second end of the magnetic bead X is connected to the first end of the first capacitor C1, the first end of the second capacitor C2, the CT pin of the primary side of the network voltage regulator chip, and the CT pin of the secondary side of the network voltage regulator chip, respectively.

[0091] The second terminal of the first capacitor C1 is connected to the first terminal of the second switch;

[0092] The second terminal of the second switch is grounded, and the control terminal is connected to the controller.

[0093] The second terminal of the second capacitor C2 is connected to the first terminal of the third switch;

[0094] The second terminal of the third switch is grounded, and the control terminal is connected to the controller.

[0095] It should also be noted that the controller can control the opening or closing of the first switch, the second switch, and the third switch to ensure that the CT pin of the primary side of the network voltage regulator chip and the CT pin of the secondary side of the network voltage regulator chip can be connected to a preset power supply or directly grounded, thereby ensuring stable compatibility with both types of PHY.

[0096] As an optional embodiment, the network transformer circuit 8 further includes: a first current-limiting resistor R10, a second current-limiting resistor R20, a third current-limiting resistor R30, a fourth current-limiting resistor R40, a first ESD transistor F1, a second ESD transistor F2, a third ESD transistor F3, and a fourth ESD transistor F4.

[0097] The first end of the first current-limiting resistor R10 is connected to the serial data positive input port of the network voltage regulator chip, and the second end is connected to the first end of the first ESD transistor F1.

[0098] The first end of the second current-limiting resistor R20 is connected to the serial data negative input port of the network voltage regulator chip, and the second end is connected to the first end of the second ESD transistor F2.

[0099] The first end of the third current-limiting resistor R30 is connected to the serial data positive receive port of the network voltage regulator chip, and the second end is connected to the first end of the third ESD transistor F3.

[0100] The first end of the fourth current-limiting resistor R40 is connected to the serial data negative receiving port of the network voltage regulator chip, and the second end is connected to the first end of the fourth ESD transistor F4.

[0101] The second terminals of the first ESD transistor F1, the second ESD transistor F2, the third ESD transistor F3, and the fourth ESD transistor F4 are all grounded.

[0102] In this invention, because the electricity meter collector is connected to the Ethernet cable via an RJ45 interface, extremely high electrostatic voltage may be introduced when a person or device interfaces with the RJ45 interface. Therefore, this solution adds a first ESD (Electro-Static Discharge) tube F1, a second ESD tube F2, a third ESD tube F3, and a fourth ESD tube F4. The ESD tubes can limit transient voltages within a safe range through clamping voltage to protect the safety of downstream circuits and the human body that comes into contact with the RJ45 interface. The ESD tubes can solve the problem of transient high voltage (such as surges) caused by lightning strikes, power switching, and disconnection of inductive loads. In addition, the ESD tubes can also filter out high-frequency noise on the Ethernet cable. Considering the possibility of overcurrent in the circuit of the electricity meter collector, this solution also includes a first current-limiting resistor R10, a second current-limiting resistor R20, a third current-limiting resistor R30, and a fourth current-limiting resistor R40 to limit the current in the circuit, prevent the electronic components in the circuit from being burned out due to excessive current, and improve the safety of the solution.

[0103] It should also be noted that, such as Figure 10 As shown, in this scheme, the network transformer circuit 8 uses the FC1008 chip for electrical isolation, signal coupling, and differential transmission. Since the PHY chip inside the network serial port pass-through chip 1 (CH9121 chip) is current-driven, the CT pin of the FC1008 chip needs to be connected to a 3.3V power supply. The ferrite bead X and capacitor are for filtering. The ESD transistor and current-limiting resistor are both EMC (Electromagnetic Compatibility) protected to protect the Ethernet communication differential signal port.

[0104] As an optional embodiment, Ethernet interface 5 is an RJ45 interface, and the electricity meter data collector also includes:

[0105] Bob Smith circuit 9 has its first Ethernet signal receiving port connected to the Ethernet signal transmitting port of network serial port pass-through chip 1. The first Ethernet signal receiving and transmitting port is connected to the Ethernet signal receiving port of network serial port pass-through chip 1. Both the second Ethernet signal receiving port and the second Ethernet signal receiving and transmitting port are connected to the Ethernet cable through an RJ45 interface.

[0106] In this invention, the Bob Smith circuit 9 has three functions: first, impedance matching: the Bob Smith circuit 9 can provide a common-mode termination for Ethernet cables, matching the characteristic impedance of the transmission line and reducing signal reflection; second, common-mode noise absorption: by guiding common-mode noise (such as external electromagnetic interference) to ground, it prevents it from coupling into the signal and avoids data errors; third, preventing signal overshoot / ringing: suppressing the reflection of high-frequency signals at the end of the transmission line, ensuring the integrity of the signal waveform (especially in 100 Mbps / 1 Gigabit Ethernet), and improving the reliability of the solution.

[0107] It should be noted that, as Figure 11 As shown, the Bob Smith circuit 9 consists of four resistors and a high-voltage ceramic capacitor. Its main function is impedance matching, because transmission lines in Ethernet are typically of relatively low impedance, while devices connected to these lines may have different impedance characteristics. The Bob Smith circuit 9 achieves impedance matching between the signal lines and devices by adding resistors and high-voltage ceramic capacitors between the signal lines and ground, thereby reducing reflections and signal loss.

[0108] It should also be noted that the 1-CH9121 network serial port transparent transmission chip has an internal Ethernet media transmission layer (MAC) and physical layer (PHY), and integrates a TCP / IP (Internet Protocol) stack, enabling bidirectional transparent transmission of network data packets and serial port data. It supports 10 / 100M, has five full-duplex / half-duplex adaptive Ethernet interfaces, is compatible with the 802.3 protocol, and supports full-duplex and half-duplex serial communication. It also supports automatic switching between RS485 transmit and receive, and can be easily configured via host computer software or serial port commands, making it convenient and quick.

[0109] It should also be noted that, such as Figure 12 As shown, this solution provides a meter data acquisition device with the 1-CH9121 network serial port pass-through chip as its core.

[0110] It should be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0111] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An electricity meter collector characterized by, include: Network serial port pass-through chip, DC-DC power conversion circuit, electricity meter signal transmission circuit, electricity meter external interface in the shape of a network port, Ethernet interface; The external interface of the electricity meter is connected to the network serial port transparent transmission chip through the electricity meter signal transmission circuit. The external interface of the electricity meter is connected to the electricity meter for mutual communication between the network serial port transparent transmission chip and the electricity meter. The input terminal of the DC-DC power conversion circuit is connected to the voltage output terminal of the meter through the external interface of the meter. The first output terminal is connected to the power supply terminal of the meter signal transmission circuit. The second output terminal is connected to the first power supply terminal of the network serial port pass-through chip. The third output terminal is connected to the second power supply terminal of the network serial port pass-through chip. This circuit is used to convert the isolation voltage transmitted by the meter into the first voltage required for the operation of the meter signal transmission circuit and the second and third voltages required for the operation of the network serial port pass-through chip. The Ethernet signal receiving port and the Ethernet signal transmitting port of the network serial port pass-through chip are both connected to the Ethernet cable through the Ethernet interface.

2. The meter reader of claim 1 wherein, The meter signal transmission circuit includes: an RS485 chip, a first resistor, a second resistor, and a third resistor; The RS485 chip's receive data output pin is connected to the serial data receive pin of the network serial port pass-through chip, and its drive data input pin is connected to the serial data transmit pin of the network serial port pass-through chip. Both the receive enable pin and the drive enable pin are connected to the RS485 transmit / receive switching control pin of the network serial port pass-through chip. The positive differential signal terminal of the RS485 chip is connected to the first terminal of the first resistor, the first terminal of the second resistor, and the positive differential signal terminal of the external interface of the meter, respectively. The negative differential signal terminal of the RS485 chip is connected to the second terminal of the second resistor, the first terminal of the third resistor, and the negative differential signal terminal of the external interface of the meter, respectively. The second end of the first resistor is connected to the first output end of the DC-DC power conversion circuit; The second end of the third resistor is connected to ground.

3. The meter reader of claim 1 wherein, Also includes: A passive crystal circuit is connected to the clock signal terminal of the network serial port pass-through chip to provide a preset clock signal to the network serial port pass-through chip.

4. The meter reader of claim 3 wherein, The passive crystal circuit includes: a passive crystal, a first load capacitor, and a second load capacitor; The external crystal oscillator input terminal of the passive crystal is connected to the positive phase input terminal of the crystal oscillation of the clock signal of the network serial port pass-through chip and the first terminal of the first load capacitor, respectively. The external crystal oscillator output terminal is connected to the inverted phase output terminal of the crystal oscillation of the clock signal of the network serial port pass-through chip and the first terminal of the second load capacitor, respectively. The second terminal of both the first load capacitor and the second load capacitor is grounded.

5. The meter reader of claim 1 wherein, Also includes: The LED circuit has its first end connected to the fourth output terminal of the DC-DC power conversion circuit, and its second end connected to the Ethernet communication connection indicator driver pin, PHY chip connection indicator driver pin, and TCP client mode indicator driver pin of the network serial port pass-through chip, respectively. The LED is used to light up when the network serial port pass-through chip is powered on and has a normal Ethernet communication connection, when the PHY chip inside the network serial port pass-through chip is working normally, and when the network serial port pass-through chip is in TCP client mode.

6. The meter reader of claim 1 wherein, The Ethernet interface is an RJ45 interface. The electricity meter data acquisition unit also includes: The network transformer circuit has a first Ethernet signal receiving port connected to the Ethernet signal transmitting port of the network serial port pass-through chip, a first Ethernet signal receiving and transmitting port connected to the Ethernet signal receiving port of the network serial port pass-through chip, and a second Ethernet signal receiving port and a second Ethernet signal receiving and transmitting port both connected to the Ethernet cable through the RJ45 interface.

7. The meter reader of claim 6 wherein, The network transformer circuit is a network voltage regulator chip. The primary side center tap CT pin of the network voltage regulator chip is connected to the preset power supply and the ground wire respectively. The secondary side center tap CT pin is connected to the preset power supply and the ground wire respectively. The first Ethernet signal receiving port is connected to the Ethernet signal transmitting port of the network serial port pass-through chip. The first Ethernet signal receiving and transmitting port is connected to the Ethernet signal receiving port of the network serial port pass-through chip. The second Ethernet signal receiving port and the second Ethernet signal receiving and transmitting port are both connected to the Ethernet cable through the RJ45 interface.

8. The meter reader of claim 7 wherein, The network transformer circuit also includes: a ferrite bead, a first capacitor, and a second capacitor; The first end of the magnetic bead is connected to the preset power supply, and the second end is connected to the first end of the first capacitor, the first end of the second capacitor, the CT pin of the primary side of the network voltage regulator chip, and the CT pin of the secondary side of the network voltage regulator chip, respectively. The second terminal of the first capacitor is grounded; The second terminal of the second capacitor is grounded.

9. The meter reader of claim 7 wherein, The network transformer circuit further includes: a first current-limiting resistor, a second current-limiting resistor, a third current-limiting resistor, a fourth current-limiting resistor, a first ESD transistor, a second ESD transistor, a third ESD transistor, and a fourth ESD transistor. The first end of the first current-limiting resistor is connected to the serial data positive input port of the network voltage regulator chip, and the second end is connected to the first end of the first ESD transistor. The first end of the second current-limiting resistor is connected to the serial data negative input port of the network voltage regulator chip, and the second end is connected to the first end of the second ESD transistor; The first end of the third current-limiting resistor is connected to the serial data positive receiving port of the network voltage regulator chip, and the second end is connected to the first end of the third ESD transistor. The first end of the fourth current-limiting resistor is connected to the serial data negative receiving port of the network voltage regulator chip, and the second end is connected to the first end of the fourth ESD transistor. The second ends of the first ESD transistor, the second ends of the second ESD transistor, the second ends of the third ESD transistor, and the second ends of the fourth ESD transistor are all grounded.

10. The meter collector of any one of claims 1 to 9, wherein, The Ethernet interface is an RJ45 interface. The electricity meter data acquisition unit also includes: The Bob Smith circuit has its first Ethernet signal receiving port connected to the Ethernet signal transmitting port of the network serial port pass-through chip, and its first Ethernet signal receiving and transmitting port connected to the Ethernet signal receiving port of the network serial port pass-through chip. Both the second Ethernet signal receiving port and the second Ethernet signal receiving and transmitting port are connected to the Ethernet cable through the RJ45 interface.

Images