Electrified LED display screen for overhead line system

Abstract

The utility model discloses an electrified LED display screen for a contact network, which comprises a direct-current high-voltage input sampling unit, an isolation sampling unit and an electrified signal processing unit which are sequentially connected, and a control card circuit and a display screen unit which are respectively connected with a driving switching control module, the electrified signal processing unit is respectively connected with the control card circuit and the driving control module, and is used for generating a corresponding trigger signal when the overhead line system is electrified or de-electrified; the control card circuit comprises a first branch circuit and a second branch circuit, the first branch circuit is used for generating a display screen driving signal when the contact network is powered on, and the second branch circuit is used for generating a display screen driving signal when the contact network is powered off; and the driving switching control module is used for switching the display screen driving signal and outputting the display screen driving signal to the display screen unit. According to the utility model, the two scanning units are adopted to generate red power-on scanning information signals and green power-off scanning information signals respectively, information is switched through a pure hardware buffer, the switching speed is higher, and the switching is safer.

Description

Technical Field

[0001] The utility model belongs to the technical field of rail transportation, and in particular relates to an electric LED display screen for a contact network. Background Art

[0002] The overhead line of the electrified track is a live device, and the live state of the overhead line is generally displayed through the live display screen in the vehicle depot. At present, in the rail transit industry, the live LED display screens used in the overhead line are mostly customized products. Once damaged, they must either be re-purchased or a custom manufacturer must be found to design new parts. The feasibility of self-repair is extremely low. Moreover, the unit drive circuit of the current overhead line LED display screen mostly adopts a constant voltage scanning method, which is prone to cause lamp bead aging, dead lights and other phenomena. In addition, the current overhead line LED display screen mostly uses a 1 / 16 scanning method, which is only suitable for use in indoor and other places with weak light. When used in semi-outdoor or outdoor places with strong light, the brightness of the displayed characters or images is insufficient. Utility Model Content

[0003] In order to solve the above technical problems, the utility model provides an electric LED display screen for contact network.

[0004] The technical solution provided by the utility model is as follows:

[0005] A powered LED display screen for a contact network comprises a DC high-voltage input sampling unit connected to the contact network, an isolation sampling unit and a powered signal processing unit connected to the DC high-voltage input sampling unit in sequence, and a control card circuit and a display screen unit respectively connected to a drive switching control module; the powered signal processing unit is respectively connected to the control card circuit and the drive control module, and is used to generate a corresponding trigger signal when the contact network is powered or powered off; the control card circuit comprises a first branch and a second branch, the first branch is used to generate a display screen drive signal when the contact network is powered on, and the second branch is used to generate a display screen drive signal when the contact network is powered off; the drive switching control module is used to switch the display screen drive signal and output it to the display screen unit; the display screen unit is used to display corresponding prompt characters when the contact network is powered on or powered off.

[0006] Furthermore, it also includes a mains power conversion unit, which is used to convert high-voltage AC mains power into low-voltage DC power to provide power supply voltage for each unit module.

[0007] Preferably, it also includes an audible and visual alarm device connected to the electrical signal processing unit, which is used to emit flashing lights and warning voice when the contact network loses power.

[0008] Further, the DC high-voltage input sampling unit includes a plurality of voltage-dividing resistors and a first photocoupler connected in series, and the isolation sampling unit includes the first photocoupler and a second photocoupler connected to the first photocoupler; the collector of the phototransistor in the first photocoupler is connected to the base of the transistor Q1 through a current-limiting resistor, and the emitter of the phototransistor in the first photocoupler is grounded; the emitter of the transistor Q1 is connected to a +5V voltage, and a resistor is connected in series between the emitter and the base of the transistor Q1, and the collector of the transistor Q1 is connected in series with the light-emitting diode in the second photocoupler and then grounded; the collector of the phototransistor in the second photocoupler is connected to a +5V voltage through a pull-up resistor, and the emitter of the phototransistor in the second photocoupler is grounded through a resistor and is connected in parallel with a buffer capacitor; the emitter of the phototransistor in the second photocoupler is used to output an electrical signal voltage INS to the electrical signal processing unit.

[0009] Furthermore, the powered signal processing unit adopts a six-way Schmitt-triggered inverter to generate trigger signals OE_R and OE_G for triggering the switching of powered and powered-off signals respectively, and also for generating trigger signals OE_RX and OE_GX for triggering the control card circuit; the trigger signals OE_RX and OE_GX are also used to trigger an external sound and light alarm device.

[0010] Furthermore, the first branch and the second branch of the control card circuit both include a communication unit, a control card and a drive buffer circuit connected in sequence; the communication unit is used to receive external instructions to perform firmware upgrades and update display information for the control card.

[0011] Preferably, the control card uses an ARM chip with a Crotex-M3 core to generate LED screen scanning information of the HUB-08 interface.

[0012] Furthermore, the display screen unit is composed of four two-color constant current dot matrix screens, which are used to display the red word "powered" when the contact network is powered or to display the green word "no power" when the contact network is powered off.

[0013] Preferably, the housing of the display screen unit is made of alloy plastic steel and is provided with a strong magnet.

[0014] Compared with the prior art, the utility model has the following beneficial effects:

[0015] The control card of the utility model adopts an ARM processor with a Cortex-M3 core, and the maximum frequency can reach 96MHz. The scanning speed used to drive the LED dot matrix is ​​fast enough, and there is no tailing, flickering and other phenomena. The utility model adopts a dedicated chip design unit driver board for constant current scanning, which has the characteristics of strong compatibility, good light efficiency, no flicker, and long service life of lamp beads. The DC high voltage signal detection of the utility model adopts a resistor voltage division method to directly take power, and sends it to the switching signal unit after two-level optical coupling isolation to ensure the safety of the voltage resistance level; and the utility model adopts a 2.4G communication method to directly modify the displayed characters and their brightness and update related programs, avoiding the tedious process of modifying the screen that requires disassembly. The utility model uses two scanning units to each generate a red "powered" and a green "no power" scanning information signal, and switches the information through a pure hardware buffer, which is faster and safer. This utility model adopts a synchronous rectification switching power supply, which has higher conversion efficiency and less heat generation than the traditional switching power supply, which is conducive to long-term uninterrupted power supply operation; and the entire LED screen uses four 4.75mm diameter patch high-brightness two-color 1 / 4 scanning constant current unit screens to form a dot matrix screen with good light efficiency and clearer light. The entire screen shell is made of alloy plastic steel, which is light and rust-proof, easy to wall-mount and hoist; at the same time, the unit screen panel is fixed by a strong magnet magnetic attraction, which is more convenient to install and disassemble. In addition, the utility model also reserves an external control interface, and other methods can be used to control the screen display information. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation to the present invention.

[0017] Figure 1 This is a schematic diagram of a powered LED display circuit module provided by an embodiment of the utility model;

[0018] Figure 2 It is a circuit diagram of DC high voltage input sampling and isolated sampling provided by an embodiment of the utility model;

[0019] Figure 3 It is a circuit diagram of an electrical signal processing unit provided in one embodiment of the utility model;

[0020] Figure 4 The utility model provides a schematic diagram of the working process of an electric LED display screen according to an embodiment of the present invention. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0022] like Figure 1 As shown, the circuit module composition of the powered LED display screen provided in this embodiment mainly includes a mains conversion unit, a DC high voltage input sampling unit, a primary isolation sampling unit, a secondary isolation sampling unit, an electrical signal processing unit, a drive switching control circuit, a display screen unit and a two-way control card circuit.

[0023] The AC power conversion unit is a power supply device that converts 220V AC power into 5V DC power. It is used to provide power supply voltage to each unit in the entire screen. Its output end adopts synchronous rectification technology. Under full load, its conversion efficiency can reach up to about 92%. Compared with the diode rectifier circuit, it has the characteristics of good stability, low heat, low power consumption and small size. It is very suitable for installation inside the LED screen.

[0024] The function of the DC high-voltage input sampling unit is to input the 750V DC high-voltage electricity drawn from the contact network into the primary isolation sampling unit after resistor voltage division, drive the diode inside the primary isolation sampling unit (photocoupler) to emit light, and obtain a level jump signal at the output end of the photocoupler. This signal is used to control the conduction of the signal of the secondary isolation sampling unit, control the conduction of the light-emitting diode inside the secondary photocoupler, and obtain a sampling signal of the presence or absence of high voltage at the output end of the secondary photocoupler. After receiving the jump signal of the secondary isolation photocoupler, the electrical signal processing unit sends it to its inverter circuit, and after amplification and buffering, three groups of trigger signals are generated: one group of signals is sent to the drive switching control circuit for switching the signal output of the two HUB-08 interfaces; one group is sent to the two control card circuits for the control card system status switching control; one group is sent to other external devices through the external interface for switching flash indication, alarm sound start control, etc.

[0025] The two control card circuits include interconnected 2.4G wireless communication units, screen control cards and drive buffer circuits. The two 2.4G wireless communication units are mainly used for wireless communication between the two screen control cards. Function 1 is to provide control card firmware upgrades. Through a proprietary protocol, instructions are sent to the control card chip to achieve the firmware wireless IAP upgrade function. Function 2 is for the two control cards to update the font sampling information and display information. Both screen control cards are dot matrix character scanning control cards, using Crotex-M3 core ARM chips. Their main function is to generate LED screen scanning information for the HUB-08 interface. The output mode can be 1 / 4, 1 / 6, 1 / 8, 1 / 16, etc. It can drive two types of LED dot matrix screens with constant voltage or constant current. The maximum driving capacity of a single card is: monochrome 64*1280, 48*1696, 32*2560; dual color 64*640, 48*848, 32*1280. The main function of the drive buffer circuit is to amplify the HUB-08 signal generated by the control card to improve its load and anti-interference capabilities, so as to drive the LED screen to display words.

[0026] The main function of the drive switching control circuit is to output two groups of HUB-08 signals with buffer driving capability at the output end of the drive switching control circuit after the control of the power signal processing unit from the four-way HUB-08 signals input by the two control cards, and send them to the signal input end of the LED dot matrix screen. When the power signal is sent, the red "powered" character control card signal is switched to the screen signal input end, and the screen displays the red power word; when the power signal disappears, the green "no power" control card signal is switched to the screen signal input end, and the screen displays the green no power word.

[0027] like Figure 2As shown, J1 and J2 are DC high voltage signal inputs, and the input voltage range is DC200~1000V. Resistors R2, R4, R6, R8, R9, and the internal light emitting diode of pin 1-2 of photoelectric coupler U1 together form a voltage divider circuit to ensure that the internal light emitting diode between pin 1-2 of U1 can be normally turned on within the input range of DC high voltage, so that the photoelectric transistor of pin 3-4 of U1 is saturated and turned on. Under the action of bias resistor R13 and current limiting resistor R10, the base of Q1 obtains voltage from +5VB, R13, R10, and GNDB, which meets the conditions for Q1 to be turned on, so that Q1 is saturated and turned on. The voltage +5VB passes through the emitter 3 and collector 2 of Q1 and is supplied to R11, the internal light emitting diode between pin 1-2 of U2, R12, and GNDB branch, so that the internal photoelectric transistor of pin 3-4 of photoelectric coupler U2 is saturated and turned on, which constitutes a DC high voltage input sampling unit and a primary isolation sampling unit. +5VA, R15, the phototransistor at pins 3-4 inside U2, R14, and buffer capacitor C1 together form a secondary isolation sampling unit, and the "powered" signal voltage INS is obtained at pin 3 of the photocoupler U2.

[0028] like Figure 3 As shown, U20 is a six-inverter chip with Schmitt trigger. R16, D5, R17, D6, R18, D2, R19, D3 and the internal inverter of U20 together form the "powered" and "no power" indication and signal output circuit (powered signal processing unit). Under the trigger of the "powered" signal INS, two trigger signal outputs are formed. OE_R is the red enable trigger signal, OE_G is the green enable trigger signal, which are used to trigger the red "powered" and green "no power" HUB-08 signal switching respectively; OE_RX is the red "powered" trigger signal of the external device and the scanning card, and OE_GX is the green "no power" trigger signal of the external device and the scanning card, which are used to trigger the generation of the red "powered" and green "no power" signals of the scanning card respectively. J3 is the output socket for triggering the external sound and light alarm signal. The resistor R20 is a current limiting resistor, which is used to trigger the "powered" signal output of the external sound and light alarm device.

[0029] The display unit uses 4 32*64 constant current unit dot matrixes, which are combined in a combination of 2 high and 2 long to form a screen that can display two 64*64 dot matrix Chinese characters. Under normal circumstances, when the high voltage of the contact network exists, it should display red "powered"; when the high voltage of the contact network disappears, it should display green "no power". Since the screen uses a high-brightness two-color SMD diode with a diameter of 4.75, the characters on the entire screen are still very clear.

[0030] like Figure 4 As shown in the figure, the working process of the whole system is as follows:

[0031] When the system is powered on and no system upgrade command is received, the MCU processor reads the program instructions stored in its ROM, initializes the peripherals, enters the main control program, displays the enable signal OE, and sends it to the trigger switch board through the two data lines of HUB-08.

[0032] In the absence of external DC high voltage trigger, the INS trigger signal is L level. After amplification by the inverter circuit, OE_R is H level, OE_G is L level, and the green "no power" character information is output, driving the 128*64 dot matrix LED screen to display the 64*64 dot matrix green "no power" character. At this time, if there is an external sound and light alarm device, a flash alarm will be issued and a high-volume warning voice of "contact network power failure, please check quickly" will be emitted.

[0033] In the case of external DC high voltage trigger, the INS trigger signal is H level, after amplification by the inverter circuit, OE_R is L level, OE_G is H level, and the red "powered" character information is output, driving the 128*64 dot matrix LED screen to display the 64*64 dot matrix red "powered" character. At this time, if there is an external sound and light alarm device, the flash alarm device will not work, and the high-volume alarm voice will be turned off.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Under the idea of ​​the present invention, the technical features in the above embodiments or different embodiments can also be combined, and there are many other changes in different aspects of the present invention as described above. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An electric LED display screen for overhead line, characterized in that: It includes a DC high-voltage input sampling unit connected to the contact network, an isolation sampling unit and an electric signal processing unit connected to the DC high-voltage input sampling unit in sequence, and a control card circuit and a display screen unit respectively connected to a drive switching control module; the electric signal processing unit is respectively connected to the control card circuit and the drive control module, and is used to generate a corresponding trigger signal when the contact network is powered or de-powered; the control card circuit includes a first branch and a second branch, the first branch is used to generate a display screen drive signal when the contact network is powered, and the second branch is used to generate a display screen drive signal when the contact network is de-powered; the drive switching control module is used to switch the display screen drive signal and output it to the display screen unit; the display screen unit is used to display corresponding prompt characters when the contact network is powered or de-powered.

2. An electrically powered LED display screen for overhead line as claimed in claim 1, characterized in that: It also includes a mains power conversion unit, which is used to convert high-voltage AC mains power into low-voltage DC power so as to provide power supply voltage for each unit module.

3. The powered LED display screen for overhead line as claimed in claim 1, characterized in that: It also includes an audible and visual alarm device connected to the electrical signal processing unit, which is used to emit flashing lights and warning voice when the contact network loses power.

4. The powered LED display screen for overhead line as claimed in claim 1, characterized in that: The DC high-voltage input sampling unit includes a plurality of voltage-dividing resistors and a first photoelectric coupler connected in series, and the isolation sampling unit includes the first photoelectric coupler and a second photoelectric coupler connected to the first photoelectric coupler; the collector of the phototransistor in the first photoelectric coupler is connected to the base of the transistor Q1 through a current-limiting resistor, and the emitter of the phototransistor in the first photoelectric coupler is grounded; the emitter of the transistor Q1 is connected to a +5V voltage, and a resistor is connected in series between the emitter and the base of the transistor Q1, and the collector of the transistor Q1 is connected in series with a light-emitting diode in the second photoelectric coupler and then grounded; the collector of the phototransistor in the second photoelectric coupler is connected to a +5V voltage through a pull-up resistor, and the emitter of the phototransistor in the second photoelectric coupler is grounded through a resistor and connected in parallel with a buffer capacitor; the emitter of the phototransistor in the second photoelectric coupler is used to output an electrical signal voltage INS to the electrical signal processing unit.

5. The powered LED display screen for overhead line as claimed in claim 4, characterized in that: The powered signal processing unit adopts a six-way Schmitt-triggered inverter to generate trigger signals OE_R and OE_G for triggering the switching of powered and powered-off signals respectively, and also to generate trigger signals OE_RX and OE_GX for triggering the control card circuit; the trigger signals OE_RX and OE_GX are also used to trigger an external sound and light alarm device.

6. The powered LED display screen for overhead line as claimed in claim 1, characterized in that: The first branch and the second branch of the control card circuit both include a communication unit, a control card and a drive buffer circuit connected in sequence; the communication unit is used to receive external instructions to perform firmware upgrades and update display information for the control card.

7. An electrically powered LED display screen for overhead line as claimed in claim 6, characterized in that: The control card adopts an ARM chip with a Crotex-M3 core to generate LED screen scanning information of the HUB-08 interface.

8. The powered LED display screen for overhead line as claimed in claim 1, characterized in that: The display screen unit is composed of four two-color constant current dot matrix screens, which are used to display the red word "powered" when the contact network is powered or to display the green word "no power" when the contact network is powered off.

9. The powered LED display screen for overhead line as claimed in claim 1, characterized in that: The shell of the display screen unit is made of alloy plastic steel and is provided with a strong magnet.

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