Diagnostic system for controlling and monitoring VMS LED lamp

Abstract

The invention relates to the field of optical fiber type variable information signs. The invention discloses a diagnostic system for controlling and monitoring a VMS LED lamp, which is used for being installed between a control line of VMS control end equipment and the LED lamp and comprises a power supply and control circuit, an LED driving circuit, a fault detection circuit, a resistive load and a controlled link, the input end of the power supply and control circuit is connected with a control line through a controlled link, the resistive load is arranged in parallel with the input end of the power supply and control circuit, the power supply and control circuit supplies power to the LED driving circuit, and the output end of the LED driving circuit is used for being connected with an LED lamp. The fault detection circuit is used for monitoring the fault state of the diagnosis system and / or the LED lamp and transmitting a fault signal to the power supply and control circuit, and the power supply and control circuit controls the controlled link to be disconnected according to the received fault signal; the power supply and control circuit detects the voltage state input by the control line and sends a corresponding dimming signal to the LED drive circuit.

Description

Technical Field

[0001] The present invention belongs to the field of optical fiber variable message signs, and in particular relates to a diagnostic system for controlling and monitoring VMS LED lamps, which is used to replace halogen lamps used in optical fiber variable message signs (VMS). Background Art

[0002] Since the 1990s, variable message signs (VMS) have been an important element of road infrastructure involving public safety. Many VMS in Europe are installed in the form of large black boxes on gantries above the road. These boxes are equipped with multiple halogen reflector lamps. Each lamp is installed in a suitable position to project light to one end of the fiber optic bundle. The other end of the fiber optic bundle is divided into many small strands and led to a surface of the box. The light points emitted at the end of the small strands form a specific dot matrix group traffic sign. Therefore, when different individual lamps in the box are lit one by one under the control of the control center, the corresponding different dot matrix group traffic signs will be lit on the same surface of the box, and the traffic signs can be changed (hence variable), forming a variable message sign (VMS) fiber optic signal light box. Because all the light emitted by the halogen reflector lamp is directed in a single direction and concentrated on the fiber optic bundle, with the light output side facing the oncoming vehicles, the traffic signs appear very bright. Colored lenses can also be added between the halogen reflector lamp and the fiber optic bundle. In addition to the original basic white light points, they can also be equipped with light points including red, green or amber. The technical requirements of VMS are stipulated in the European standard EN12966 "Road Vertical Signs - Variable Information Traffic Signs". In the prior art, patent application DE4212124A1 also introduces a VMS system with optical fiber signs, halogen lamps and control terminal equipment.

[0003] There are competing technologies in the VMS market, such as large display boards that use arrays of LED matrix panels. The advantage of such panels is the ability to dynamically display graphics and alphanumerics in different sizes and colors. However, the initial acquisition cost of such LED panels is still high, not to mention that all control end equipment, mounting structures and software need to be updated at the same time to support the changes, so LED panels are more suitable for installation in strategic locations or new locations. Many simple VMS still operate satisfactorily in the form of fiber optic signal boxes, which have been operating for many years with reliable infrastructure support. Fiber-based VMS ensures clear identification of traffic signs, even in extreme weather conditions such as fog, rain, snow, sun, etc., and can display a variety of selected information (preset text and / or symbols in different colors) on a single screen. Maintenance work is reduced to replacing only the light source (lamp) instead of replacing the expensive LED matrix panel.

[0004] The commonly used halogen reflector lamps in VMS fiber optic signal light boxes (VMS signal light boxes) are 42V 65W50mm diameter with K2d lamp heads, providing 230 lumens output and an expected life of 2400 hours (100 days). Currently, LED lamps with similar lumen output have a lifespan of 10 times (2-3 years) or longer than their halogen counterparts. Updating all VMS lamps to LEDs will help reduce operating / maintenance costs and lower carbon footprint.

[0005] There are multiple suppliers in various regions that provide VMS control terminal infrastructure equipment. Their control and monitoring functions are basically the same, but there are also some subtle differences. The main features of the control terminal equipment supported by the present invention are:

[0006] Provide 42V rectified AC power to light the lamp to Full output;

[0007] Provide 34V rectified AC power to light the lamp to Dim (darkness) output;

[0008] Provides 36V battery DC power to light the lights in emergency situations;

[0009] (Some control-end devices only provide phase-cut rectified AC voltage in Full / DIM operation);

[0010] The sensor is in normal operation (voltage and current) when the light is on;

[0011] When the light is off, use a low level or short pulse to detect whether the light is normal.

[0012] When a light "failure" is detected, the console alerts the operator and stops using the light.

[0013] Conventional MR16 or GU10 retrofit LED lamps have similar physical dimensions to halogen reflector lamps, but they do not meet direct replacement requirements because they operate at much lower currents than halogen lamps, which results in control-side sensing failures. In addition, if a major component in the LED driver circuit fails, the retrofit LED lamp may not automatically communicate the fault status back to the existing control-side equipment. Summary of the invention

[0014] The object of the present invention is to provide a diagnostic system for controlling and monitoring VMS LED lamps, which is installed between the control line of the VMS control end device and the LED lamp so as to provide the necessary control and monitoring functions for this part of the VMS and directly replace the VMS halogen lamp without any changes to the control end device.

[0015] To achieve the above-mentioned purpose, the present invention provides a diagnostic system for controlling and monitoring VMS LED lamps, which is used to be installed between the control line of the VMS control end device and the LED lamp, and includes a power supply and control circuit, an LED drive circuit, a fault detection circuit, a resistive load and a controlled link; the input end of the power supply and control circuit is connected to the control line through the controlled link, the resistive load is arranged in parallel with the input end of the power supply and control circuit, the power supply and control circuit supplies power to the LED drive circuit, the output end of the LED drive circuit is used to connect the LED lamp, the fault detection circuit is used to monitor the fault state of the diagnostic system and / or the LED lamp and transmit the fault signal to the power supply and control circuit, and the power supply and control circuit controls the controlled link to be disconnected according to the received fault signal; the power supply and control circuit detects the voltage state of the control line input and sends a corresponding dimming signal to the LED drive circuit.

[0016] During normal operation, the VMS control end device provides different operating and test voltages to the diagnostic system. The diagnostic system senses the input voltage status and provides FULL (full scale) or DIM (dark scale) output current levels to the LED lamp to provide different brightness outputs. The resistive load draws an operating current similar to that of a halogen lamp after replacing the LED lamp, allowing the VMS control end device to sense the normal operating voltage and current, thereby determining that no fault has occurred.

[0017] When a fault occurs in the LED lamp, or the power and control circuit of the diagnostic system, or the LED drive circuit, its fault detection circuit will detect the problem, causing the power and control circuit to trigger the controlled link disconnection and separate the resistive load and the diagnostic system from the VMS control end device, resulting in no current flowing. When the VMS control end device detects an abnormal working current, it stops the circuit from working and alerts the operator to perform maintenance.

[0018] In some embodiments, the controlled link is composed of a relay and a fuse, the fuse is arranged in parallel with the contacts of the relay, and the contacts are in a closed circuit state during normal operation.

[0019] In some embodiments, the relay is a SET-RESET type latching relay, and the fuse is a time-delay fuse.

[0020] In some embodiments, the fault detection circuit monitors the LED lamp current and the output of the power supply and control circuit respectively through connecting lines. When a fault occurs, the fault detection circuit RESETs the controlled link to a disconnected state through the power supply and control circuit through the connecting lines.

[0021] In some embodiments, the power supply and control circuit distributes and regulates the voltage provided from the control line for use by the LED driver circuit and all other circuits in the diagnostic system.

[0022] In some embodiments, the power supply and control circuit also has an auxiliary power supply to provide redundant power supply to continue operating the controlled link in the event of a failure of the main power supply in the power supply and control circuit.

[0023] In some embodiments, the power supply and control circuit controls the on / off operation and dimming function of the LED driving circuit according to the voltage and / or the phase cutting time on the control line.

[0024] In some embodiments, the LED driving circuit is dimmed and controlled from the power supply and control circuit via connecting wires, and the output of the LED driving circuit is connected to the LED lamp via connecting wires, and is connected to the fault detection circuit via connecting wires.

[0025] In some embodiments, the resistive load includes an internal resistive load and an optional connector, the optional connector is arranged in parallel with the internal resistive load, and the optional connector is used to connect to the external resistive load.

[0026] In some embodiments, a box is also included, in which the power supply and control circuit, LED drive circuit, fault detection circuit, internal resistance load and controlled link are all arranged, and the optional connector, LED lamp connector and input terminal connection wires are all extended out of the box.

[0027] Beneficial technical effects of the present invention:

[0028] The diagnostic system of the present invention cooperates with the LED lamp to directly replace the VMS halogen lamp without any change to the control terminal equipment, thereby reducing the workload and cost of the existing VMS transformation, while reducing the operation / maintenance cost and carbon footprint. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 A prior art conceptual diagram of a VMS fiber optic matrix traffic sign illuminated by halogen lamps is shown, where each lit lamp displays a corresponding traffic sign on the surface of the VMS signal light box;

[0031] Figure 2 A diagram showing the appearance of a prior art halogen lamp used in a VMS fiber optic matrix traffic sign - a small glass reflector type halogen lamp with two connecting wires and a connector;

[0032] Figure 3An example block diagram showing different functions in a prior art VMS control terminal device;

[0033] Figure 4 It is a flow chart showing the operation logic of the control terminal equipment;

[0034] Figure 5 yes Figure 1 Conceptual image of a VMS fiber-optic matrix traffic sign using LED lights as the light source. Each LED light requires a diagnostic system to support its operation;

[0035] Figure 6 A diagram showing the structure of the plastic box of the diagnostic system;

[0036] Figure 7 shows a simplified block diagram of the diagnostic system of the present invention;

[0037] Figure 8 shows a functional block diagram of a preferred embodiment of the diagnostic system of the present invention;

[0038] Fig. 9 It is a table showing the relationship between the diagnostic system and the control end functions. DETAILED DESCRIPTION

[0039] To further illustrate the various embodiments, the present invention provides drawings. These drawings are part of the disclosure of the present invention, which are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, a person of ordinary skill in the art should be able to understand other possible implementations and advantages of the present invention. The components in the figures are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0040] The present invention will now be further described with reference to the accompanying drawings and specific implementation methods.

[0041] Figure 1 1 is a conceptual diagram of a prior art VMS system 100, which is composed of a control terminal device 101 connected to a VMS signal light box 103 via a control line 102. The control line 102 is respectively connected to different halogen lamps in the VMS signal light box 103, such as 104a, 104b and 104c, and the halogen lamps 104a, 104b and 104c respectively irradiate the light to the optical fiber bundles 105a, 105b and 105c. The optical fiber bundles 105a, 105b and 105c are further divided into many small bundles and distributed on the sign surface 106 of the VMS signal light box 103 to form a plurality of light spots. The plurality of light spots are arranged into common traffic signs, such as speed limit numbers 107a, staff 107b and arrows 107c. Sometimes, multiple groups of lights and light bundles can also be used in conjunction with colored lenses to form a combined sign, such as a red circle with a white speed limit of 50 and two amber dots with switches flashing on the side.

[0042] Figure 2 Features of a prior art halogen lamp 200 (104) commonly used in a VMS signal light box 103 are described. The lamp is composed of a halogen bulb 201, a glass reflector lamp body 202, an insulating end cap 203, two connecting wires 204a / 204b and a connector 205a / 205b. A fixture is provided in the VMS signal light box 103 for fixing the halogen lamp 200 in place so that the light can be directly projected and focused onto one end of the optical fiber bundle. A corresponding lamp line connector is placed next to the fixture to connect the halogen lamp 200 to the corresponding control position of the halogen lamp 200 in the control terminal device 101 via the control line 102.

[0043] The general control functions of the prior art control terminal device 300 (101) are as follows: Figure 3 As described above, each lamp is connected to a control location 301 of a corresponding halogen lamp in a control terminal device 300 (101). A single control terminal device 300 can accommodate a plurality of similar control locations 301, which share a common power control and user interface device 302.

[0044] Each control location 301 has two sets of switches: a selector switch 3011, an ON / OFF switch 3012, and a set of sensing circuits 3013. The selector switch 3011 selects different voltages under the command of the user interface 302: 42Vrms 3011a, 34Vrms 3011b, and 36Vdc 3011c for normal light operation and a test voltage 3011d for testing when the light is not on. The selected voltage is then connected to the ON / OFF switch 3012 to perform the "on" 3012a, "off" 3012b functions, and the flashing function 3012c, which is a series of continuous cycles on / off, used to operate, for example, an amber flashing logo.

[0045] Before the operator selected voltage is transmitted to the control line 303 (102), it passes through a set of voltage 3013a and current 3013b sensing devices to detect and ensure that the halogen lamp connected to the other side of the control line 303 (102) is operating within predetermined upper and lower voltage and current limits. When the control line 303 (102) is detected to be operating outside of those predetermined limits, the sensing devices will actively shut down the associated control location 301 and notify the operator through the user interface 302 in the control terminal device 300 (101).

[0046] Figure 4 yes Figure 3 The internal operation flow chart of the prior art control terminal device 300 (101) is used as an example to control the halogen lamp in the VMS signal light box. These operation flows are also applicable to the LED lamp and diagnostic system of the present invention.

[0047] All operations stop until a lamp is selected for lighting or testing.

[0048] When the operator wants to light a lamp, he will start the operation by inputting instructions from the user interface 302. The control end device 300 checks the input parameters, knows that the user wants to light the lamp, sets the output switch 3012 to ON 3012a, and then sets the correct level output through the selection switch 3011.

[0049] When the lamp is on, the system control function on the user interface 302 will start a timer to periodically check whether the output voltage 3013a and current 3013b are within the control range. If the detection results are outside the acceptable range, the system will issue a fault alarm to the operator. If everything is normal, the lamp will continue to light until there is a shutdown command from the user interface 302, and the control position will compare the operating status and switch the ON / OFF switch 3012 to OFF 3012b.

[0050] In some cases, the operator wants to perform some tests to verify whether the halogen lamp that has not been lit for a long time is still intact, and the sign must not be lit during the test to avoid affecting traffic. The user interface 302 can issue a test command to send a low voltage test level or a short duration voltage pulse 3011d through the selection switch 3011, so that the halogen lamp will not receive enough energy to light up, but the system can still draw the corresponding current through the control line 303 (102) and detect success through the sensor terminal 3013 to confirm the healthy state of the halogen lamp.

[0051] The VMS signal light box 103 based on halogen lamp can be transformed into Figure 5 The VMS signal light box 503 suitable for LED lamps does not require any modification to the original VMS control terminal device 101 and the control line 102. Other components in the VMS signal light box 503, such as the optical fiber bundle 105a / 105b / 105c and the dot matrix traffic signs 107a / 107b / 107c on the sign surface 106, have not changed. The diagnostic system 500a / 500b / 500c is inserted between the control line 102 and the LED lamp 504a / 504b / 504c. The LED lamp 504a / 504b / 504c used in this example is a simple lamp based on COB LED without any internal driving circuit or other electronic equipment. The illumination output and physical installation size of the LED lamp 504a / 504b / 504c match the VMS halogen lamp.

[0052] Figure 6It shows that the diagnostic system 500 can be constructed as a plastic diagnostic system box 5003 with electronic equipment inside. Its input terminal connection wires 5004a / 5004b and connectors 5005a / 5005b are the same as halogen lamps 204a / 204b and 205a / 205b, and can be directly replaced. The polarized connector 5002 (i.e., LED lamp connector) is used to connect one of the LED lamps 504a / 504b / 504c, and the optional connector 5001 can be used to connect an optional external large-size resistor load to withstand the same large operating current as the halogen lamp, so that the halogen lamp can be replaced with an LED lamp with the diagnostic system 500 without modifying the control terminal device 101.

[0053] If you want to further reduce the carbon footprint in the future, you can make slight modifications to the control end device 101 to reduce the sensing current and change the resistance load value of the diagnostic system 500 to reduce power consumption. Therefore, you can disconnect and remove the external large-size resistance load connected to the optional connector 5001, and only use a small internal resistance load to meet the already reduced current detection requirements of the control end device.

[0054] Figure 7 This is a simplified block diagram of the diagnostic system 500 of the present invention to facilitate understanding of its working principle, and all of its main functions are included in the diagnostic system box 5003.

[0055] The voltage signal of the control end device 101 is input from the control line 102 and connected to the internal resistance load 5008 and the power supply and control circuit 5010 through the connector 5005a / 5005b, the connecting line 5004a / 5004b and the controlled link 5009. A large-sized external resistance load is connected in parallel with the internal resistance load 5008 through the optional connector 5001, which can increase the power of the resistance load to match the halogen lamp, while keeping the size of the diagnostic system box 5003 small and easy to install near the LED lamp.

[0056] The power circuit part of the power supply and control circuit 5010 obtains the input voltage from the controlled link 5009 (on state) through the power connection line 520, and provides appropriate power to the LED drive circuit 5006 and the fault detection circuit 5007 through the connection lines 521 and 522 respectively. The control circuit part of the power supply and control circuit 5010 detects the input voltage state to determine the LED lamp current level and sends a dimming control signal to the LED drive circuit 5006 via the connection line 511.

[0057] The output 531 of the LED driver circuit 5006 is branched to the polarized connector 5002 through the connection line 533, and to the fault detection circuit 5007 through the connection line 532. When there is an abnormality or fault in the connection line 522 or the connection line 532 input of the power circuit, the fault detection circuit 5007 will generate an output 512 to the control circuit in the power supply and control circuit 5010, resulting in a fault signal to control and disconnect the controlled link 5009 via the connection line 510. When the control link 5009 is open, the control line 102 is separated from the power connection line 520, the internal resistance load 5008 and the optional connector 5001, and the control end device 101 detects that there is no current passing and issues an alarm.

[0058] There are many ways to construct the functions in the diagnostic system 500. The controlled link 5009 can be a relay, a trip switch or a semiconductor switch, etc. The power supply and control circuit 5010 can be a microcontroller or even just a timer and controlled output device formed by several logic gates and power transistors. The LED drive circuit 5006 is a driver with analog or PWM dimming control, and the fault detection circuit 5007 can be an optocoupler with logic circuits, all of which are well-known technologies.

[0059] Figure 8 is a more detailed block diagram of a diagnostic system according to a preferred embodiment of the present invention.

[0060] The controlled link 5009 is constructed as a fuse 50091 and relay contacts 50092a connected at both ends thereof. The relay contacts 50092a are one part of the set (SET)-reset (RESET) type latching relay 50092 and are directly controlled by the latching relay 50092. When the input operating voltage of the control line 102 is activated, the power connection line 520 is activated and the power circuit 5010a of the power supply and control circuit 5010 is started. Then the control circuit 5010b of the power supply and control circuit 5010 starts to work. The latching relay 50092 is locked to the set (SET) state through the connection line 510, resulting in the relay contacts 50092a being closed. Most of the operating current flows through the closed relay contacts 50092a, bypassing the fuse 50091.

[0061] Fuse 50091 is a time-delay fuse with a rated current of approximately 10-20% of the normal operating current, so if relay contact 50092a is open at the beginning of operation, fuse 50091 will not blow immediately, leaving time for latching relay 50092 to close relay contact 50092a and provide a bypass for fuse 50091. However, if latching relay contact 50092a does not enter the set (SET) state for any reason and remains open, and the operating current flows through fuse 50091 for a time exceeding the time-delay specification of fuse 50091, fuse 50091 will blow, isolating power connection line 520, internal resistance load 5008 and optional connector 5001 from control line 102.

[0062] The bridge rectifier 540 is placed between the internal resistive load 5008 and the power connection line 520, so that the control line 102 can be connected without considering the electrical polarity. As an option, a larger resistive load can be placed externally through an optional connector 5001, so that the diagnostic system housing 503 can be kept small and easy to install and maintain.

[0063] The power connection line 520 distributes the input voltage to: a) the power supply circuit 5010a to supply the control circuit 5010b; b) the low voltage power supply circuit 5011a provides low voltage power (e.g., 12V) to other internal circuits in the diagnostic system 500 through the low voltage line 559; c) the LED driver power supply circuit 553 that controls the on / off operation of the LED drive circuit 5006, and d) the auxiliary redundant low voltage power supply 552a.

[0064] The control circuit 5010b in this embodiment is a timing and control circuit based on CMOS logic gates, which obtains power through its power circuit 5010a through the power connection line 520 and the low voltage line 559. At the initial start, the control circuit 5010b generates a short duration setting (SET) voltage, which is connected to the latching relay 50092 via the connection line 510 to lock it in the setting (SET) position and close the relay contact 50092a. It also provides a delayed start for the power circuit 553 of the LED driver circuit 5006 through the connection line 513. This is because when the lamp is in the off state, the control terminal device 101 may send a low voltage or short pulse to the VMS circuit to check the continuity of the circuit. Although such a pulse cannot light up the halogen lamp, it can still provide enough energy for the LED driver circuit 5006, resulting in a visible short flash of the LED lamp, which is undesirable. It is necessary to suppress the test pulse connection so that the LED driver circuit 5006 is only lit when the control line 102 sends the normal working power supply voltage.

[0065] LED driver circuit 5006 can be any LED driver solution on the market with dimming control and suitable input voltage range (e.g. 25-60vdc) and output voltage and current levels to match the LED lamp. (e.g. 18V 350mA COB type LED)

[0066] The control circuit 5010 b generates a dimming signal according to the working voltage level reflected to the power connection line 520 by the voltage state from the control terminal device 101 , and then dims the LED driving circuit 5006 through the connection line 511 .

[0067] Fig. 9 A table of output voltages from the control terminal is shown, along with the corresponding behavior from the diagnostic system 500. When the control terminal voltage is 42Vrms, the LED driver circuit 5006 gives a full-scale output. When the control terminal voltage drops to 34Vrms or 36Vdc, the dimming signal controls the LED driver circuit 5006 via the connection line 511 and adjusts the output of the LED driver circuit 5006 to a DIM output (e.g., 50% drive current). The control terminal voltage of 17.5Vrms is too low for the LED driver circuit 5006, and the pulse test is suppressed by the power supply circuit 553 of the LED driver circuit 5006 via the connection line 513 of the control circuit 5010b, so the LED driver circuit 5006 has no output for both test voltages.

[0068] The output 531 from the LED driver circuit 5006 is monitored by the fault detection circuit 5007 before being sent to the connection line 5002. When the diagnostic system 500 is running but no current is flowing to the LED lamp, a fault signal will be generated on the connection line 5121.

[0069] The auxiliary redundant low voltage power supply 552a is composed of a simple voltage regulator, which is responsible for resetting the latching relay 50092 when the low voltage power supply 5011a fails. The auxiliary redundant low voltage power supply 552a ensures the normal state of the power supply and LED output current by monitoring the fault signal connection line 5121, the power connection line 520, and the low voltage line 559. And in the event of a fault, it provides sufficient voltage output to send a reset (RESET) voltage to the latching relay 50092 through the connection line 5122, resetting (RESET) the latching relay 50092 from the previously latched setting (SET) position.

[0070] As previously described, the reset (RESET) of the latching relay 50092 opens the relay contact 50092a, and after a short delay, the operating current blows the fuse 50091, electrically isolating the diagnostic system 500 from the control line 102. Fig. 9It can be seen that when the latching relay 50092 is in the reset (RESET) state, the LED driving circuit 5006 will have no output, and the control end device 101 is in the Failure Isolation state. When the control end device 101 senses that there is no current reaching the diagnostic system 500, it will isolate the circuit and remind the operator to perform maintenance service.

[0071] Although the present invention has been specifically shown and described in conjunction with the preferred embodiments, it should be understood by those skilled in the art that various changes may be made to the present invention in form and details without departing from the spirit and scope of the present invention as defined by the appended claims, all of which are within the scope of protection of the present invention.

Claims

1. A diagnostic system for controlling and monitoring VMS LED lamps, which is installed between the control line of the VMS control terminal device and the LED lamp, characterized in that: It includes a power supply and control circuit, an LED driving circuit, a fault detection circuit, a resistive load and a controlled link; the input end of the power supply and control circuit is connected to the control line through the controlled link, the resistive load is arranged in parallel with the input end of the power supply and control circuit, the power supply and control circuit supplies power to the LED driving circuit, the output end of the LED driving circuit is used to connect the LED lamp, the fault detection circuit is used to monitor the fault state of the diagnostic system and / or the LED lamp and transmit the fault signal to the power supply and control circuit, and the power supply and control circuit controls the controlled link to be disconnected according to the received fault signal; the power supply and control circuit detects the voltage state of the control line input and sends a corresponding dimming signal to the LED driving circuit.

2. The diagnostic system for controlling and monitoring a VMS LED lamp according to claim 1, characterized in that: The controlled link is composed of a relay and a fuse. The fuse is arranged in parallel with the contacts of the relay. The contacts are in a closed circuit state during normal operation.

3. The diagnostic system for controlling and monitoring a VMS LED lamp according to claim 2, characterized in that: The relay is a SET-RESET type latching relay, and the fuse is a time-delay fuse.

4. The diagnostic system for controlling and monitoring a VMS LED lamp according to any one of claims 1 to 3, characterized in that: The fault detection circuit monitors the LED lamp current and the output of the power supply and control circuit respectively through the connection lines. When a fault occurs, the fault detection circuit resets the controlled link to a disconnected state through the power supply and control circuit through the connection lines.

5. The diagnostic system for controlling and monitoring a VMS LED lamp according to claim 1, characterized in that: The power supply and control circuit distributes and regulates the voltage provided from the control line for use by the LED drive circuit and all other circuits in the diagnostic system.

6. The diagnostic system for controlling and monitoring a VMS LED lamp according to claim 5, characterized in that: The power supply and control circuit also has an auxiliary power supply to provide redundant power supply to continue operating the controlled link in the event of a failure of the main power supply in the power supply and control circuit.

7. The diagnostic system for controlling and monitoring a VMS LED lamp according to claim 1, characterized in that: The power supply and control circuit controls the on / off operation and dimming function of the LED driving circuit according to the voltage and / or the phase cutting time on the control line.

8. The diagnostic system for controlling and monitoring a VMS LED lamp according to claim 1, characterized in that: The LED driving circuit is dimmed and controlled from the power supply and control circuit via connecting wires, and the output of the LED driving circuit is connected to the LED lamp via connecting wires, and is also connected to the fault detection circuit via connecting wires.

9. The diagnostic system for controlling and monitoring a VMS LED lamp according to claim 1, characterized in that: The resistive load includes an internal resistive load and an optional connector. The optional connector is arranged in parallel with the internal resistive load, and the optional connector is used to connect to an external resistive load.

10. The diagnostic system for controlling and monitoring a VMS LED lamp according to claim 9, characterized in that: It also includes a box, in which a power supply and control circuit, an LED driving circuit, a fault detection circuit, an internal resistance load and a controlled link are all arranged, and an optional connector, an LED lamp connector and an input terminal connection line are all extended out of the box.

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