CN113299055B

CN113299055B - Digital display device

Info

Publication number: CN113299055B
Application number: CN202110537940.4A
Authority: CN
Inventors: 王运良; 陈伟
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-05-18
Filing date: 2021-05-18
Publication date: 2022-06-21
Anticipated expiration: 2041-05-18
Also published as: CN113299055A

Abstract

The invention provides a digital display module aiming at the characteristics of strong function and multiple display parameters of a digital instrument, which is powered by input alternating current and comprises a power supply interface, a power supply circuit, a power consumption circuit and a function expansion interface, wherein the function expansion interface comprises a terminal A and a terminal B, and when the digital display module is externally connected with a current transformer, the measurement and display of current can be realized; and a certain pin of the function expansion interface and a certain pin of the alternating current power supply interface are combined for use, so that different functions can be realized.

Description

Digital display device

Technical Field

The invention relates to a digital display device, which is particularly suitable for alternating current output electrical equipment such as an alternating current generator set, an inverter and the like.

Background

The common inverter power supply and alternator group electrical equipment in the market is generally provided with a display instrument. With the progress of digital technology in recent years, digital intelligent meters are increasingly popularized to be used in the equipment, besides the functions of indicating parameters such as voltage and current of old-fashioned pointer meters, some digital intelligent meters also have the functions of recording and storing fault data, and a user can record operation history information through the meters and provide data support for later maintenance of the equipment.

Because the digital instrument has more functions, one or more keys are generally used for parameter setting or display data switching. Because the key needs to be provided with the hole and the adhesive film on the instrument shell, in some damp and vibrating strong current detection occasions of 220V or 380V, the adhesive film is easy to fall off to cause direct exposure of circuits in the instrument, so that the display fault of the instrument is caused slightly, and the safety accidents such as electric shock and the like are caused seriously.

Patent document CN213070415U discloses a digital display device, which mainly realizes multi-parameter rotation display by an automatic circulation mode of parameters to be displayed. The method is suitable for some common detection instruments, and users of the instruments only need to see required data in the using process without setting any parameters of the instruments. For some middle and high-end tables with monitoring and fault data recording functions, the method is slightly insufficient.

In addition, when the output voltage and frequency are unstable due to the failure of the ac power generating equipment or even no ac power is output, the digital display device with the failure record storage function cannot operate due to the absence of ac power supply, and the failure data stored therein cannot be read normally.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, and provides a digital display module aiming at the characteristics of high waterproof requirement of a digital instrument, more data to be displayed and data reading requirement under the condition of power generation equipment failure;

another object of the present invention is to further provide a digital display device.

The purpose of the invention is realized by the following technical scheme:

a digital display module is powered by input alternating current and comprises a power supply interface, a power supply circuit, a power consumption circuit and a function expansion interface;

the power supply circuit is arranged between the power supply interface and the power consumption circuit and is used for performing voltage reduction rectification on alternating current input from the power supply interface and supplying the alternating current to the power consumption circuit after the alternating current is stabilized;

the power supply interface comprises two terminals, wherein one terminal a is directly connected to the negative pole of the output of the power supply circuit or is reversely connected to the negative pole of the output of the power supply circuit through a diode;

the power consumption circuit comprises a display and an MCU (microprogrammed control unit), the power supply circuit is connected with the MCU, the power supply circuit supplies power to the MCU, and the MCU is connected with the display;

the function expansion interface comprises two terminals:

the terminal A and the terminal B, terminal A is connected to MCU directly or through resistance, parallelly connected a resistance between terminal A and the terminal B, when external current transformer, this resistance plays the effect of current sampling, at least one in two terminals is connected to the output positive pole or the input positive pole of supply circuit voltage regulator device through the diode, when linking this terminal to DC power supply positive pole to when being connected to power supply interface terminal a with the DC power supply negative pole, realize not having this display module DC supply under the alternating current input condition.

Further, the power consumption circuit further comprises a voltage reduction circuit, the voltage reduction circuit at least comprises a resistor, the terminal B is connected to the output end of the voltage reduction circuit, when the power consumption circuit is externally connected with a current transformer, the output of the voltage reduction circuit and alternating current signals output by the transformer are superposed and transmitted to the MCU, current measurement is achieved, and relevant parameters are displayed through the displayer.

Further, the step-down circuit includes two divider resistors that are connected, terminal B connects between two divider resistors, and when external current transformer, the output of step-down circuit and the alternating current signal of mutual-inductor output superpose and transmit for MCU, realize the measurement of electric current.

Further, the function expanding interface terminal B is connected to the positive electrode of the output end or the positive electrode of the input end of the voltage stabilizing device of the power supply circuit through a diode, when the positive electrode of the direct current power supply is connected to the terminal and the negative electrode of the direct current power supply is connected to the power supply interface terminal a, direct current power supply to the display module under the condition of no alternating current input is realized, at the moment, the resistor connected in parallel between the two terminals of the function expanding interface plays a role of pulling up the resistor, and the voltage of the terminal a is pulled up to the voltage of the direct current power supply.

Further, a specific short-circuit time is set in the MCU preset software to be associated with corresponding function calling, and when direct current is supplied, the power supply interface terminal a and the function expansion interface terminal A are short-circuited for a specific time, so that the following effects are achieved: the display module measures display parameter settings; different combinations of different display parameters and different time lengths are carried out, and automatic cycle display is carried out; displaying abnormal data in a fault diagnosis mode; the timing prompt and alarm function is turned on or off; and/or, clearing the display time.

Furthermore, the digital display module also comprises an infrared receiving device, and the infrared receiving device receives an instruction of an external infrared remote controller and transmits the instruction information to the MCU.

Further, a specific infrared instruction is set in the MCU preset software to be associated with corresponding function calling, so that the following effects are achieved: measuring display parameter settings; different combinations of different display parameters and different time lengths are carried out, and automatic cycle display is carried out; automatically recording the detected abnormal data, and displaying the abnormal data in a diagnosis mode according to an infrared remote control instruction; the timing prompt and alarm function is turned on or off; resetting the running time record; and/or, display data calibration.

Further, the display module also comprises a wireless communication module, wherein the wireless communication module can be a short-distance Bluetooth and/or wifi module and the like, or a Zig-Bee, an Ultra Wideband (UWB), Near Field Communication (NFC) and the like, and also can be a long-distance wireless transmission technology, such as GPRS/CDMA, a data transmission radio station, spread spectrum microwave, a wireless bridge and satellite communication, a short-wave communication technology and the like. Or a combination of both.

The invention further provides a display device comprising the digital display module. The display device comprises the digital display module and a shell, wherein the digital display module is embedded into the shell, and except for an alternating current input interface and a function expansion interface, pins of other components and parts and a circuit board bonding pad are sealed by pouring sealant, so that the waterproof and shock-resistant purposes are realized.

Furthermore, the shell of the display device is dark transparent or semitransparent, and infrared signals can be transmitted under the condition that no opening is formed on the surface of the shell.

In the invention, because the display device has no keys, the front shell does not need to be provided with holes, all the components on the PCB assembly, except the alternating current input interface and the function expansion interface, pins and pads of other components can be sealed by pouring sealant, thus the display device is further suitable for occasions with high requirements on water resistance and shock resistance, and if the alternating current input interface and the function expansion interface adopt waterproof connectors, the whole display device can completely reach the waterproof grade of IP 67.

Aiming at the characteristic of more measurement parameters of the digital display device, the function expansion interface with one or two pin terminals is arranged on the circuit board of the display device, so that the functions of current measurement, parameter setting display, timing prompt and alarm are realized, fault record data stored in the display device can be called out, and auxiliary judgment is provided for overhauling and maintaining power generation equipment. Aiming at the problem that the display device cannot normally operate because of no alternating current power supply caused by equipment faults, the direct current positive electrode is connected to a certain needle of the function expansion interface, and the direct current negative electrode is connected to a certain needle of the alternating current input interface, so that the direct current power supply of the display device is realized, and the recorded data reading of the fault equipment is realized under the condition of no alternating current.

Compared with the display instrument equipped by the existing inverter power supply and the electrical equipment such as the alternating current generator set, the display device provided by the invention is only provided with two-pin interfaces, and combines an internal exquisite and simple circuit structure, so that the display device provided by the invention is small and compact, low in cost and rich in use scenes, and can prompt a client to perform targeted maintenance on the equipment regularly after the timing prompt and alarm functions are started, such as engine oil replacement, air filter cleaning and the like, aiming at the gasoline and diesel generator set, and the display device has good market prospect.

Drawings

Fig. 1 is a schematic block diagram of a power supply and function expansion interface in embodiment 1 of the present invention;

fig. 2 is a schematic block diagram of a power supply and function expansion interface according to embodiment 5 of the present invention;

fig. 3 is a circuit configuration diagram of a step-down rectifier module according to

embodiment

1 or 5 of the present invention;

fig. 4 is a circuit configuration diagram of another step-down rectifier module in

embodiment

1 or 5 of the present invention;

fig. 5 is a circuit configuration diagram of another step-down rectifier module in

embodiment

1 or 5 of the present invention;

fig. 6 is a software control flow chart of the function expansion interface of the present invention for switching different functions.

The voltage-reducing rectifier circuit comprises a power supply interface 1, a terminal 1a, a terminal 1B, a terminal 2, a power supply circuit 21, a voltage-reducing rectifier module 22, a capacitor 23, an LDO voltage-stabilizing device 24, a capacitor 3, a microcontroller MCU 4, a resistor 5, a diode 6, a resistor 7, a voltage-reducing circuit 71, a divider resistor 72, a divider resistor 8, an equivalent low-voltage load 9, a function expansion interface 9A, a terminal 9B and a terminal.

Detailed Description

The present invention is further described below in conjunction with the appended drawings, but should not be construed as limiting the invention. Any modification and decoration without departing from the spirit and substance of the present invention falls within the scope of the present invention.

The expression of a resistor or a diode in the present invention means that a resistor or a diode can be implemented, but does not exclude the use of two or more series components. However, in case of being able to implement the function, a solution should be superior in circuit simplicity and cost.

Example 1

As shown in fig. 1, in this example, the two terminals of the power supply interface 1 (ac power input interface) are a terminal 1a and a terminal 1b, respectively. The power supply circuit 2 includes a buck rectifier module 21, a capacitor 22, an LDO regulator 23, and a capacitor 24. The power consumption circuit comprises an MCU3, a voltage reduction circuit 7 and an equivalent low-voltage load 8. The voltage-reducing circuit 7 includes a voltage-dividing resistor 71 and a voltage-dividing resistor 72. The equivalent low-voltage load 8 comprises modules or components such as a display, an infrared receiver and the like.

The function expansion interface 9 has a two-terminal structure including a terminal 9A and a terminal 9B. The terminal 9A is connected to the ADC pin of the microcontroller MCU3 through a resistor 4. The terminal 9B is connected between the voltage dividing resistor 71 and the voltage dividing resistor 72 of the step-down circuit 7, and is connected to the output terminal anode of the LDO regulator device 23 through the diode 5. A transformer sampling resistor 6 is connected in parallel between the terminal 9A and the terminal 9B.

In this example, ac power is input to two ends 1a and 1B of the power supply interface 1 of the digital display device, as shown in fig. 3, the ac power passes through a capacitor C1, a rectifier bridge B1, a resistor R3 and a voltage regulator D1 to realize the functions of resistance-capacitance voltage reduction and full-bridge rectification, and finally the voltage output to two ends of the capacitor 22 is stabilized within a certain range, so as to ensure that the LDO voltage regulator device 23 operates stably, and the stable dc power Vcc output by the LDO voltage regulator device 23 is supplied to a digital control part with the microcontroller MCU3 and other equivalent low-voltage loads 8 as the core.

Two ends of the mutual inductor sampling resistor 6 are respectively connected in parallel to two

pin terminals

9A and 9B of the function expansion interface 9, and the terminal 9A is connected to an ADC pin of the microcontroller MCU3 through the resistor 4; the terminal 9B is connected to one end of a voltage dividing resistor 71 and one end of a voltage dividing resistor 72 of the voltage dropping circuit 7, the other end of the voltage dividing resistor 71 is connected to the anode of the output end of the LDO voltage regulator 23, the other end of the voltage dividing resistor 72 is connected to the cathode of the output of the power supply circuit 2, and the terminal 9B is also connected to the anode of the output end of the LDO voltage regulator 23 through a diode 5.

When the two ends of the function expanding interface 9 are connected with the current transformer, the current transformer outputs an alternating voltage signal which is in direct proportion to the current detected by the transformer through the transformer sampling resistor 6, and if the resistances of the divider resistor 71 and the divider resistor 72 are equal, the signal is approximately raised by Vcc/2; through the matching of the sampling resistor 6 of the mutual inductor, the signal fluctuates between 0 and Vcc, and the micro controller MCU3 can sample and calculate the signal in real time so as to realize the measurement of the current.

When no ac power is input to the two ends 1a and 1B of the power supply interface 1, the terminal 9B of the function expansion interface 9 is connected to the positive electrode of the 5V dc power supply, and the terminal 1a of the power supply interface is connected to the negative electrode of the 5V dc power supply, so that the dc power supply forms a loop through the diode 5, the digital control circuit taking the microcontroller MCU3 and other equivalent low-voltage loads 8 as the core, and the internal diode of the rectifier bridge B1 in fig. 3, and realizes dc power supply to the digital control circuit taking the microcontroller MCU3 and other equivalent low-voltage loads 8 as the core. At this time, the terminal 9A is short-circuited to the terminal 1a of the power supply interface 1, the voltage of the input function expansion terminal 9A is changed from Vcc to 0V, the microcontroller MCU3 is interrupted by the timer, digital sampling is performed on the voltage signal of the function expansion terminal 9A every 200 μ s, if the sampled voltage value is less than 0.2V, the terminal 9A is considered to be short-circuited to the

terminal

1a, and 1 is added to the value of the count register t 1; until the sampled voltage value is detected to rise from 0V to approximately Vcc again, when the value of T1 is greater than the minimum effective value T1, the different values of the T1 register correspond to different instructions, including parameter settings and internal historical data displays.

The minimum effective value T1 is set to 200, namely when the short-circuit time of the two terminals of the terminal 1a and the terminal 9A is less than 40ms, the system does not react, and therefore misjudgment caused by instantaneous impact of current sampling can be effectively avoided.

Presetting software in a microcontroller MCU3, setting specific short-circuit time in the preset software to be associated with corresponding function calling, and when direct current is supplied, short-circuiting the power supply interface terminal 1a and the function expansion interface terminal 9A for specific time to realize: the display module measures display parameter settings; different combinations of different display parameters and different time lengths are carried out, and automatic cycle display is carried out; displaying abnormal data in a fault diagnosis mode; the timing prompt and alarm function is turned on or off; and/or, clearing the display time. And can be set at the moment of power-on, the watch displays main configuration and software version number data in a flashing mode, the flashing time can be set to be maintained for 0.5 second or a plurality of seconds, so that after-sales personnel can judge whether the function setting is correct, and after the flashing is finished, the system enters a normal mode and starts to circularly display.

Similarly, when the infrared receiver is integrated, the same function as the terminal short circuit is realized by setting a specific infrared instruction in the MCU preset software and associating the specific infrared instruction with the corresponding function call. The advantage of using an infrared receiver is that the operability of the instructions is stronger.

The software control flow for switching different functions of the function expanding interface is shown in fig. 6.

Example 2

This example is substantially the same as example 1, except that: the terminal 9A of the two-pin function expansion interface 9 is connected to the ADC pin of the microcontroller MCU3 through the resistor 4, and is connected to the positive electrode of the output terminal of the LDO regulator 23 through a diode. The terminal 9B is connected between the voltage dividing resistor 71 and the voltage dividing resistor 72 of the voltage reducing circuit 7, and a transformer sampling resistor 6 is connected in parallel between the terminal 9A and the terminal 9B.

When no alternating current is input into the two

ends

1a and 1b of the power supply interface 1, the positive electrode of the 5V direct current power supply is connected to the terminal 9A of the function expansion interface 9, and the negative electrode of the 5V direct current power supply is connected to the terminal 1a of the power supply interface, so that direct current power supply for the display device is realized.

Example 3

This example is substantially the same as example 1, except that: the terminal 9A of the two-pin function development interface 9 is connected to the ADC pin of the microcontroller MCU3 through the resistor 4. Terminal 9B is connected to the negative output terminal of power supply circuit 2 only through resistor 72 and to the positive output terminal of LDO regulator 23 through diode 5. A transformer sampling resistor 6 is connected in parallel between the terminal 9A and the terminal 9B.

When the current transformer is connected to the two ends of the function expanding interface 9, the current transformer outputs an alternating voltage signal which is proportional to the current detected by the transformer through the transformer sampling resistor 6, the negative half cycle of the signal is clamped to the negative electrode of the output end of the power supply circuit 2 by the protection diode in the MCU body, and the MCU3 realizes the current measurement by sampling the positive half cycle of the signal in real time.

When no alternating current is input into the two ends 1a and 1B of the power supply interface 1, the positive electrode of the 5V direct current power supply is connected to the terminal 9B of the function expansion interface 9, and the negative electrode of the 5V direct current power supply is connected to the terminal 1a of the power supply interface, so that direct current power supply for the display device is realized.

Example 4

This example is substantially the same as example 1, except that: the terminal 9A of the two-pin function development interface 9 is connected to the ADC pin of the microcontroller MCU3 through the resistor 4. Terminal 9B is connected to the output terminal anode of power supply circuit 2 only through resistor 71 and to the output terminal anode of LDO regulator device 23 through diode 5. A mutual inductor sampling resistor 6 is connected in parallel between the terminal 9A and the terminal 9B.

When the current transformer is connected to the two ends of the function expanding interface 9, the current transformer outputs an alternating voltage signal proportional to the current detected by the transformer through the transformer sampling resistor 6, the signal and the positive voltage of the output end of the LDO voltage regulator 23 are superposed and output to the ADC pin of the MCU3, the positive half cycle of the signal is clamped to the positive electrode of the output end of the power supply circuit 2 by the protection diode in the MCU, and the MCU3 realizes the current measurement by sampling the negative half cycle of the signal in real time.

Example 5

This embodiment is substantially the same as embodiment 1 except that a diode 5 is connected to the input terminal anode of the LDO regulator device 23 (fig. 2). When no ac power is input to the two terminals 1a and 1B of the power supply interface 1, the terminal 9B of the function expansion interface 9 is connected to the positive electrode of the 5V dc power supply, and the terminal 1a of the power supply interface is connected to the negative electrode of the 5V dc power supply, so that the dc power supply forms a loop through the diode 5, the LDO regulator 23, the digital control circuit with the microcontroller MCU3 and other equivalent low-voltage loads 8 as the core, and the internal diode of the rectifier bridge B1 in fig. 3. The LDO voltage regulator device 23 converts the input 5V direct current into 3.3V, and realizes the direct current power supply of a digital control circuit taking the microcontroller MCU3 and other equivalent low-voltage loads 8 as cores.

Example 6

The embodiment is basically the same as embodiment 1, except that when the value of the counter register T1 is greater than the set value T1, the parameter setting mode is entered, the MCU 3IO port connected to the terminal 9A through the resistor is set to the general IO port mode or the serial port mode, and the external communication module is used to perform parameter setting or history data reading on the display device.

Example 7

This embodiment is substantially the same as embodiment 1, except that the buck rectifier module 2 is a resistor-capacitor buck half-bridge rectifier circuit shown in fig. 4 instead of the resistor-capacitor buck full-bridge rectifier circuit shown in fig. 3.

Example 8

This embodiment is substantially the same as embodiment 1, except that the buck rectifier module 2 is a switched buck circuit shown in fig. 5 instead of the rc buck full bridge rectifier circuit shown in fig. 3.

Example 9

This embodiment is substantially the same as embodiment 1, except that the equivalent low-voltage load 8 further includes a wireless communication module such as a bluetooth module and/or a wifi module. At this time, the infrared receiver may or may not be present. By adopting the Bluetooth module or the wifi module, the display device can realize the information communication between the display device and a control terminal (such as a mobile phone, a tablet or a computer) with Bluetooth or wifi, and realize the setting of the MCU3, the online updating of the MCU3 preset software, the storage and backup of running information and the like. In addition, the abnormal display device can be warned at the control end, and timely maintenance is facilitated. When a plurality of display devices exist, the display devices can be numbered and monitored, so that the monitoring time is greatly saved, and the working efficiency is improved.

Claims

1. A digital display module is supplied with power by input alternating current and is characterized by comprising a power supply interface, a power supply circuit, a power consumption circuit and a function expansion interface;

the function expansion interface comprises two terminals:

the display module comprises a terminal A and a terminal B, wherein the terminal A is directly or through a resistor connected to the MCU, a resistor is connected in parallel between the terminal A and the terminal B, when the terminal A is externally connected with a current transformer, the resistor plays a role of current sampling, at least one of the two terminals A or B is connected to an output positive electrode or an input positive electrode of a voltage stabilizing device of the power supply circuit through a diode, and when a direct-current power supply positive electrode is connected to the terminal and a direct-current power supply negative electrode is connected to a power supply interface terminal a, direct-current power supply to the display module under the condition of no alternating-current input is realized;

setting specific short-circuit time in the MCU preset software to be associated with corresponding function calling, and when the direct current is supplied, short-circuiting the power supply interface terminal a and the function expansion interface terminal A for specific time to realize that: the display module measures display parameter settings; different combinations of different display parameters and different time lengths are carried out, and automatic cycle display is carried out; displaying abnormal data in a fault diagnosis mode; the timing prompt and alarm function is turned on or off; and/or, clearing the display time.

2. The digital display module of claim 1, wherein the power consuming circuit further comprises a voltage dropping circuit, the voltage dropping circuit comprises at least one resistor, the terminal B is connected to an output end of the voltage dropping circuit, when the current transformer is externally connected, an output of the voltage dropping circuit and an alternating current signal output by the transformer are superposed and transmitted to the MCU, so as to measure the current.

3. The digital display module according to claim 2, wherein the voltage-reducing circuit comprises two voltage-dividing resistors connected with each other, the terminal B is connected between the two voltage-dividing resistors, and when the current transformer is externally connected, the output of the voltage-reducing circuit and the alternating current signal output by the transformer are superposed and transmitted to the MCU, so as to measure the current.

4. The digital display module as claimed in claim 1, wherein the function expansion interface terminal B is connected to the positive terminal of the output terminal or the positive terminal of the input terminal of the voltage regulator device of the power supply circuit through a diode, and when the positive terminal of the dc power supply is connected to the terminal and the negative terminal of the dc power supply is connected to the power supply interface terminal a, the display module is supplied with dc power without ac input, and at this time, the resistor connected in parallel between the two terminals of the function expansion interface functions as a pull-up resistor to pull up the voltage of the terminal a to the voltage of the dc power supply.

5. The digital display module according to any one of claims 1 to 4, further comprising an infrared receiving device, wherein the infrared receiving device receives an instruction from an external infrared remote controller and transmits the instruction information to the MCU.

6. The digital display module of claim 5, further comprising a wireless communication module, wherein the wireless communication module is a Bluetooth and/or wifi module.

7. The digital display module of claim 5, wherein a specific infrared instruction is set in the MCU preset software to be associated with a corresponding function call, so as to realize: measuring display parameter settings; different combinations of different display parameters and different time lengths are carried out, and automatic cycle display is carried out; automatically recording the detected abnormal data, and displaying the abnormal data in a diagnosis mode according to an infrared remote control instruction; the timing prompt and alarm function is turned on or off; resetting running time records; and/or, display data calibration.

8. A display device comprising the digital display module of any one of claims 1 to 7.

9. The display device of claim 8, comprising the digital display module and a housing, wherein the digital display module is embedded in the housing, and pins of other components and circuit board pads are sealed by pouring sealant except for the alternating current input interface and the function expansion interface.

10. A display device as claimed in claim 8 or 9, characterized in that the housing is dark-colored transparent or translucent and allows transmission of infrared signals without openings in the surface.