CN204422633U - Current monitoring system - Google Patents

Abstract

The utility model discloses this current monitoring system that a kind of the utility model provides, comprise current measuring device, current measuring device comprises MCU mainboard, power module, line current sample circuit, line voltage distribution sample circuit, board turning lamp circuit and watchdog circuit; This system also comprises handhold read-write device; Current measuring device and the equal built-in with wireless module of handhold read-write device, current measuring device carries out data interaction by communication and handhold read-write device.Handhold read-write device of the present utility model adopts panel computer to carry wireless module, and is communicated with current measuring device by the data interactive mode of radio communication, effectively reduces communications cost; In addition, the utility model adopts three layers of Power supply mode and low power dissipation design, ensure that the reliability of system while reducing maintenance cost.Applicability of the present utility model is strong, and Consumer's Experience is friendly.

Description

Current Monitoring System

technical field

The utility model relates to a current monitoring system.

Background technique

The utility model patent with the publication number CN201320000884 discloses an online current monitor for distribution lines, which includes a current monitor, an induction coil installed on a phase wire of the distribution line, and the induction coil is wrapped with a silicone rubber insulating layer. The current monitor includes a signal acquisition module, a GSM short message module, a single-chip microcomputer and a display, and a DC power supply for supplying power to the above-mentioned components. The signal collection module, the single-chip microcomputer and the display are connected in sequence, and the induction coil is connected to the signal collection module through wires. The signal collection module is connected to the GSM SMS module connection.

The utility model patent with the publication number CN201420053006 discloses a wireless temperature monitoring system based on RFID, including a measurement chip and a handheld reader. The measurement chip includes a single-chip microcomputer control circuit, a temperature recorder, a temperature sensor, a power conversion circuit and Wireless module; the handheld reader includes a wireless module, a button adjustment circuit, a single-chip microcomputer control circuit, a liquid crystal display circuit, an audible and visual alarm system and a system power supply.

The prior art has the following problems: 1. GSM text message transmission has a limited amount of data, and the cost of text messages is high; 2. The sampling solar power supply method has high maintenance costs; 3. The hand-held reader uses buttons to control, and the interface is not friendly.

Utility model content

The purpose of the utility model is to provide a low-cost, energy-saving and reliable current monitoring system.

The current monitoring system provided by the utility model includes a current measuring device, and the current measuring device includes an MCU main board, a power module, a line current sampling circuit, a line voltage sampling circuit, a flop lighting circuit and a watchdog circuit; the system also includes Handheld reader-writer; both the current measurement device and the handheld reader-writer have built-in wireless modules, and the current measurement device interacts with the handheld reader-writer through wireless communication.

The power module includes a CT power-taking circuit, a rechargeable backup power supply and a lithium battery. The rechargeable backup power supply uses a farad capacitor. The lithium battery is a one-time backup power supply.

The handheld reader includes PDA, USB HUB circuit, USB-to-UART circuit and wireless module; the USB interface of PDA is connected to the wireless module via the USB-to-UART circuit through the USB HUB circuit. The PDA adopts a tablet computer.

The line current sampling circuit includes a current transformer CT and a signal conditioning circuit.

The handheld reader of the utility model adopts a tablet computer equipped with a wireless module, and communicates with the current measuring device through the data interaction mode of wireless communication, effectively reducing the communication cost; in addition, the utility model adopts a three-layer power supply mode and low power consumption Designed to ensure system reliability while reducing maintenance costs. The utility model has strong applicability and friendly user experience.

Description of drawings

Fig. 1 is a functional block diagram of the utility model.

Fig. 2 is a functional block diagram of the current measuring device of the present invention.

Fig. 3 is a functional block diagram of the handheld reader-writer of the present invention.

Fig. 4 is the HUB circuit diagram of the USB of the present invention.

Fig. 5 is a circuit diagram of USB to UART of the present invention.

Fig. 6 is a UART and wireless module interface circuit diagram of the utility model.

Fig. 7 is a work flow diagram of the utility model.

Detailed ways

As shown in Figure 1, the utility model includes a current measuring device and a handheld reader. Both the current measurement device and the handheld reader have built-in wireless modules, and the current measurement device is connected to the handheld reader PDA through wireless communication for data interaction.

As shown in Figure 2, the current measuring device of the present invention includes a MCU main board, a power supply module, a wireless module, a line current sampling circuit, a line voltage sampling circuit, a flop lighting circuit and a watchdog circuit. The line current sampling circuit includes a current transformer CT and a signal conditioning circuit.

The power module includes a CT power-taking circuit, a rechargeable backup power supply and a lithium battery. The rechargeable backup power uses farad capacitors. Lithium battery is a one-time backup power supply.

The utility model adopts a three-layer power supply mode to ensure that the service life is not less than 10 years. The first layer is the CT power-taking circuit; if the current on the line is greater than NA, then the CT power-taking circuit is sufficient for the normal use of the current measurement device without consuming battery power at all. The second layer is a rechargeable backup power supply, and the utility model can adopt a farad capacitor; if the current on the line reaches the capacitor charging condition, then the electric quantity stored in the capacitor can also be used by the current measuring device when the line current becomes small. The third layer is the lithium battery. When the line current is less than NA, the CT will not consume enough power for the normal use of the current measurement device, and the battery will be consumed.

The sampling frequency of the current measuring device of the present utility model is 1KHz, that is, 20 points are sampled per cycle, so as to ensure the sampling accuracy.

As shown in Figure 3, the handheld reader includes four parts: PDA, USB HUB circuit, USB to UART circuit and wireless module. The USB interface of the PDA is expanded to four-way USB through the USB HUB circuit, which is convenient for subsequent function expansion; on this basis, a group of USB is selected to be converted into a UART through the USB-to-UART circuit, so as to realize the control operation of the wireless module.

The PDA of the present utility model can adopt tablet computer.

As shown in Figure 4, the PDA USB of the present utility model is expanded to four-way USB by expansion chip U1, facilitates follow-up function expansion; The model that expansion chip U1 can adopt Texas Instruments is the conversion chip of TUSB2046BI.

The pin 1 of the standard USB interface conversion chip U1 is connected to the power supply V3P3 through the resistor R13; the pin 1 is also grounded through the capacitor C14, and the pin is also connected to the pin 3 of the Mini-USB interface chip J10 through the resistor R10; the pin of the conversion chip U1 Pin 2 is grounded through capacitor C15, and this pin is also connected to pin 2 of Mini-USB interface chip J10 through resistor R11; pin 3 and pin 25 of the conversion chip U1 are connected to power supply V3P3; pin 26 is connected to power supply through resistor R150 V3P3 connection; its 29 pins and 30 pins are connected with a crystal oscillator circuit; its 4 pins are connected to the reset pin of the PDA for transmitting the reset signal RST; its 6 pins and 8 pins are connected to the power supply V3P3 through the resistor R112; its 11 Pins and 12 pins, 15 pins and 16 pins, 19 pins and 20 pins, 23 pins and 24 pins form a total of four downstream ports, of which the fourth port is connected to the standard USB-to-serial port interface; its 7 pins, 27 pins, 28 feet and 31 feet are grounded.

The standard USB interface conversion chip U1 adopts the bus power supply mode.

Pin 1 of the Mini-USB interface chip J10 is connected to the power supply VBUS through an adjustable resistor PTC1; its pins 4, 5 and 6 are all grounded.

As shown in Figure 5, the circuit diagram of USB to UART of the present invention, wherein the conversion chip U3 can adopt the chip of model FT232R of FTDI Company.

The 4 pins of the conversion chip U3 are connected to the power supply V3P3, and this pin is also grounded through the capacitor C32; its 20 pins are connected to the bus power supply VBUS; its 15 pins and 16 pins are connected to the standard USB interface conversion chip in the Mini-USB to standard USB interface circuit The fourth port of U1 is connected; its 19th pin is connected to the bus power supply VBUS through the resistor R31, and this pin is also grounded through the resistor R30; its 1st and 5th pins are used as serial ports to connect with the serial port of the wireless module, and 1st pin is the sending port , 5 feet is the receiving port; its 7 feet, 18 feet, 21 feet, 25 feet and 26 feet are all grounded.

As shown in FIG. 6, the wireless module of the present invention includes a wireless transceiver chip U4. The serial port of the wireless transceiver chip is connected to the serial port of the conversion chip U3 in the standard USB-to-serial port interface, and its antenna terminal is connected to the antenna ANT4.

The working principle of the utility model is: the current measurement device takes electricity through the current transformer CT in the line current sampling circuit, and converts the measured non-electrical quantity signal of the transmission line into a periodic signal through the signal conditioning circuit in the line current sampling circuit. Then the periodic signal is converted into a pulse signal, and the pulse signal is transmitted to the MCU; the MCU saves the result in the EEPROM through the judgment and processing of the internal program, and waits for the staff to use the handheld reader to obtain the data and process it.

As shown in Figure 7, the use steps of the handheld reader-writer of the present utility model are as follows:

Step 1, open the PDA, click to enter the APP application software;

Step 2, select the address serial number of the device to be tested, as well as the start and end dates, and click to start the data test;

Step 3, after the data interaction is successful, the PDA automatically draws the current monitoring curve according to the start and end dates. During the data interaction process, there will be a timeout retransmission mechanism and verification to ensure the validity and continuity of the data.

The current measuring device of the utility model records a real-time sampling average value every 5 minutes, and writes it into the EEPROM after verification. The advantage of this processing is to avoid data loss when the current measuring device is powered off or reset, and also increases the reliability of reading and writing EEPROM.

Claims (7)

1. A current monitoring system comprises a current measuring device, and the current measuring device comprises an MCU main board, a power supply module, a line current sampling circuit, a line voltage sampling circuit, a flop lighting circuit and a watchdog circuit; it is characterized in that the system also Including the handheld reader; both the current measurement device and the handheld reader have built-in wireless modules, and the current measurement device performs data interaction with the handheld reader through wireless communication. 2. The current monitoring system according to claim 1, wherein the power module comprises a CT power-taking circuit, a rechargeable backup power supply and a lithium battery. 3. The current monitoring system according to claim 2, wherein the rechargeable backup power supply uses a farad capacitor. 4. The current monitoring system according to claim 2, wherein the lithium battery is a one-time backup power supply. 5. The current monitoring system according to claim 1, characterized in that, said handheld reader-writer comprises a HUB circuit of PDA, USB, a USB to UART circuit and a wireless module; the USB interface of PDA is passed through the HUB circuit of USB The USB to UART circuit is connected with the wireless module. 6. The current monitoring system according to claim 5, wherein the PDA adopts a tablet computer. 7. The current monitoring system according to claim 1, wherein the line current sampling circuit comprises a current transformer CT and a signal conditioning circuit.