WO2011006411A1

WO2011006411A1 - Dc fan fault detecting device and method with alarm

Info

Publication number: WO2011006411A1
Application number: PCT/CN2010/074137
Authority: WO
Inventors: 张新永
Original assignee: 中兴通讯股份有限公司
Priority date: 2009-07-13
Filing date: 2010-06-21
Publication date: 2011-01-20
Also published as: CN201474944U

Abstract

A fault detecting device having an alarm used for DC fans, and corresponding method. The fault detecting device comprises several fan fault detection circuits connected in parallel. All the fan fault detection circuits are connected to an input end of a signal processing unit. One end of the first current-limiting resistor in each fan fault detection circuit is connected to a power supply, and the other end is connected to the input end of the signal processing unit and the alarm signal of a fan. The method determines whether the fans have faults by judging the states of LEDs.

Description

Fault detecting device and method for DC fan with alarm output

Technical field

The invention belongs to a detecting device, and particularly relates to a fault detecting device and method for a DC fan with an alarm output.

Background technique

In existing power electronic equipment, the loss of heat itself is large, so it is often necessary to borrow a fan to cool it. The power supply in the electronic control device is mostly provided by the DC source, and the DC fan is easy to adjust, so the DC fan is often used in electronic equipment. Compared with the AC fan, the DC fan needs to add components to convert from DC to AC, so the DC fan is prone to failure. Usually, the DC fan will be blocked, open, or out of position. When the fault occurs, the heating parts of the equipment may be damaged due to overheating. Therefore, accurate and timely detection of fan failures appears to be important.

Currently, DC fans are classified into two types: no alarm output and alarm output. A fan with no alarm output, only the power and ground leads are provided. If you need to detect the fan status, you need to pass the external circuit. Most of the current methods are to detect the fan current. Because there are some shortcomings in the fault detection method of this fan, more and more users start to use the alarm output. DC fan, this fan has a fan alarm signal in addition to the power and ground leads, and the reasonable handling of the fan alarm signal is particularly important.

The existing fan detection method with alarm output is to connect a suitable pull-up resistor and power supply to the output fan alarm signal. The user generally determines whether the fan is normal according to the level conversion of the fan signal. As shown in FIG. 1( a ), it is a schematic diagram of a fault detecting circuit for outputting a DC fan with an alarm signal, which is mainly implemented by the signal processing unit 1 . Fault detection; Figure 1 (b) is a schematic diagram of the fan connection plug 2 in the circuit shown in Figure 1 (a).

Summary of the invention

The existing fault detection method needs to separately process multiple fault signals when processing multiple fans, so that more channels are detected; when the fan is reversely connected, the rear-stage circuit and the fan are damaged. Bad, and the alarm signal output of the fan is susceptible to level fluctuations due to interference factors such as temperature and power supply, and fluctuations in the level may cause subsequent detection of the circuit.

The technical problem to be solved by the present invention is to provide a fault detecting apparatus and method for a DC fan having an alarm output, which can simultaneously detect a fault of a plurality of fans and indicate a faulty fan by an alarm light.

In order to solve the above problem, the present invention discloses a fault detecting device for a DC fan having an alarm output, the device comprising a plurality of parallel fan fault detecting circuits, wherein all fan fault detecting circuits are connected to an input end of the signal processing unit, wherein One end of the first current limiting resistor in each of the fan fault detecting circuits is connected to the power source, and the other end of the first current limiting resistor is connected to the input end of the signal processing unit and the alarm signal of the fan.

In the above device, each of the fan fault detecting circuits further includes an LED and a second current limiting resistor, one end of the first current limiting resistor is connected to the power source, and the other end is connected to the alarm signal of the fan and An anode of the light emitting diode, a cathode of the light emitting diode is connected to one end of the second current limiting resistor, and the other end of the second current limiting resistor is connected to an input end of the signal processing unit.

The signal processing unit is implemented by an optocoupler or a triode.

When the signal processing unit is implemented by using an optocoupler, one end of the second current limiting resistor is connected to the input end of the primary side of the optocoupler, the output end of the optocoupler primary side is grounded, and the input end of the optocoupler secondary side is connected. The power supply, the output of the optocoupler secondary side outputs a detection signal, and the output terminal is grounded through a pull-down resistor.

When the signal processing unit is implemented by a triode, one end of the second current limiting resistor is connected to the base of the triode, and the base of the triode is also grounded through a voltage dividing resistor, and the collector of the triode is connected to the power source. The emitter of the triode outputs a detection signal.

In the same way, the first current limiting resistor and the second current limiting resistor have the same or different resistance values.

The resistance values of the first current limiting resistors in the different fan fault detecting circuits are the same or different. The resistance values of the second current limiting resistors in the different fan fault detecting circuits are the same or different. The present invention also provides a method for detecting a fault of a DC fan having an alarm output of a fault detecting device for a DC fan having an alarm output, the method comprising: determining a light emitting diode finger If the indicator light is on, it is determined that the fan is faulty. If the LED indicator is off, it is determined that the fan is normal.

After the step of determining that the fan is faulty, the method further includes: indicating, by the alarm signal, the faulty fan.

The technical solution of the present invention uses a multi-channel shared fault detection circuit, which can detect faults of multiple fans at the same time, and only needs to provide one fault output signal to explain the existence of a fan fault, and the faulty fan is indicated by the warning light. The faulty fan is easy to find. In addition, the invention not only realizes the detection and processing of the alarm signals in the case of multiple DC fans in position, disconnection, blocking, and reverse connection, but also realizes effective protection of the fan and the detection circuit when the fan is reversely connected, and improves the fault detection circuit. The anti-interference ability makes fault detection more reliable and accurate. BRIEF abstract

1( a ) is a schematic diagram of a fault detecting circuit for a DC fan with an alarm signal output in the prior art;

Figure 1 (b) is a schematic view of the fan connection plug in the circuit shown in Figure 1 (a);

Figure 2 is a schematic circuit diagram of the present invention;

FIG. 3 is a schematic diagram of a circuit for implementing signal processing by using an optocoupler in the embodiment; FIG.

Figure 4 (a) is a schematic diagram of a circuit for implementing signal processing using the PC817 optocoupler in the practical application of the present invention;

Figure 4 (b) is a schematic view of the fan connection plug in the circuit shown in Figure 4 (a);

Fig. 5 is a circuit diagram showing the signal processing by the triode in the embodiment. Preferred embodiment of the invention

The technical solutions of the present invention are further described in detail below with reference to the accompanying drawings and specific embodiments.

A fault detecting device for a DC fan with an alarm output, as shown in FIG. 2, includes a plurality of parallel fans, and for each fan fault detecting circuit, a current limiting resistor R is required. One end is connected to the power supply 1 (ie VCC1), the other end is connected to the anode of the light-emitting diode VD, the cathode of the light-emitting diode is connected to one end of the current limiting resistor RL, and the other end of the resistance RL is connected to the input of the signal processing unit 1, the fan alarm The signal (FAN-F) is connected to the anode of the light-emitting diode VD.

Wherein, in the same fan fault detecting circuit, the resistance of the current limiting resistor R and the current limiting resistor RL may be the same or different; and for different fan fault detecting circuits, all the current limiting resistors R (ie, the entire device) In the current limiting resistor R), the resistor of the same resistance value can be selected, or the resistors with different resistance values can be selected respectively. Similarly, the current limiting resistor RL in the whole device can also select the resistor with the same resistance value, or different resistance can be selected. The resistance of the value.

The working process of the above device will be described below.

First, the alarm signal of the DC fan in each fan fault detection circuit can be defined as

FAN—Fx, (x=l, 2, 3...), the alarm signal terminal is connected to VCC1 through the current limiting resistor R. When the fan is working normally, the signal FAN-Fx is kept low, the current is flowing in the current limiting resistor R, and no current flows through the current limiting resistor RL and the LED VD. At this time, the optocoupler in the signal processing unit or The triode is in an off state, and the LED indicator is off;

When the fan is blocked or disconnected, the signal FAN-Fx is in a high-impedance state, that is, the signal

FAN—Fx will remain high. Thus, the photocoupler primary or triode base has current from VCC1 through current limiting resistor R, LED VD, and current limiting resistor RL. When the optocoupler or transistor is turned on, the LED indicator lights up, prompting the user that the fan of the road is faulty.

When the fan plug is reversed, the LED indicator lights up, and because the current limiting resistor RL is used, the signal processing unit does not cause overcurrent burnout due to abnormal alarm signals. At the same time, the internal alarm of the fan The circuit will not be damaged. That is, the current limiting resistor RL acts as a reverse connection protection. In addition, the alarm output signal of the fan is also susceptible to fluctuations due to external interference such as temperature and power supply under normal working conditions. The use of the current limiting resistor RL can also improve the anti-interference ability of the fault detection circuit.

In the above device, the signal processing unit 1 can be implemented by using the photocoupler 10 or the transistor 11. When the signal processing unit is implemented by an optocoupler, according to the specifications and the requirements of the circuit, the primary and secondary sides of the optocoupler can be connected or separated, and the size of the current limiting resistors R and RL can be calculated according to the optocoupler specifications; In the case of a triode, the fan ground and the detection signal ground must be identical, and the resistance of the current limiting resistor needs to be calculated according to the turn-on characteristics of the triode. The following is a description of the circuit when the signal processing unit 1 is implemented by the optocoupler 10. As shown in FIG. 3, one end of the current limiting resistor RL is connected to the input end of the primary side of the optocoupler, and the other end of the optocoupler is connected to the VCC1 ground; One end of the secondary side of the optocoupler is connected to VCC2, and the other end of the secondary side is connected to the ground of VCC2 through a pull-down resistor R', wherein VCC1 and VCC2 can be connected in common or non-co-connected; , ' , , , , , specifically, taking the number of detected fans as 5 as an example, to introduce a fault detecting device that uses an optocoupler to implement signal processing. At this time, the fault detecting device selects a PC817 optocoupler 101, as shown in FIG. 4 . ( a ) shows that the primary and secondary sides of the optocoupler have a common ground current of 2 mA, which means that the conduction current is satisfied. The recommended maximum current should not exceed 50 mA. The LEDs use Φ3 red LEDs to work. The current is between 1 and 10 mA, and the current limiting resistors R and RL are both 5.1K resistors. Figure 4 (b) is a schematic view of the fan connector plug 2 in the circuit of Figure 4 (a).

When a fan is blocked, the optocoupler input current is 2.4 mA (ie, the minimum operating current), and the current meets the LED operating requirements, that is, the LED indicator light in the fan fault detection circuit becomes bright; when five fans When fully blocked, the optocoupler input current is 12 mA (ie, the maximum operating current), and the indicators of the LEDs in the five-way fan fault detection circuit are all brightened. It can be seen that the maximum and minimum operating currents are Optocoupler recommended within the working range. For light-emitting diodes, the 1N4148 can be used because its recommended maximum current is 200 mA, which can meet the circuit requirements. The resistance loss is calculated by 0.05W, and the resistor with a power of 1/4W is selected as the current limiting resistor to meet the circuit requirements.

Moreover, the experiment shows that in the fan fault detecting circuit formed by the above parameters, when the fan is in normal operation, the optocoupler is turned off, the red LED is extinguished, and the detection signal is a low level signal; when any one or more fans are blocked When the switch is turned, disconnected, and the fan is reversed, the fan fault detection circuit will start the optocoupler operation, the detection signal is a high level signal, and the corresponding red LED is lit, and the output of the signal processing unit is detected. The signal level can determine the fan failure, and the faulty fan can be specifically located through the illuminated red LED.

Next, the circuit when the signal processing unit 1 is implemented by the transistor 11 is introduced. As shown in FIG. 5, one end of the current limiting resistor RL is connected to the base of the triode, and the voltage dividing resistor R" is terminated to the base of the triode. The other end of the voltage dividing resistor R" is connected to the power ground. When using an NPN or PNP transistor, The emitter connection is connected to the pull-up or pull-down resistor R', the collector is connected to VCC2, and the signal output from the emitter is the detection signal of the fan fault detection circuit.

It can be seen from the above embodiment that the device of the present invention uses a multi-channel shared fault detection circuit for a DC fan with an alarm output to realize fault detection of multiple fans and indicate a faulty fan through an alarm light, and the entire detection The processing circuit outputs a detection signal. In addition, the method can also effectively protect the fan and the processing circuit when the fan is reversely connected, and improve the anti-interference ability of the fault detecting circuit.

The present invention also provides a method for detecting a fault of a DC fan having an alarm output by using the fault detecting device of the DC fan having the alarm output, the method comprising: determining whether the LED indicator is on, if the LED indicates If the light is on, it is determined that the fan is faulty. If the LED indicator is off, it is determined that the fan is normal.

In addition, the principle of detecting the fault by applying the above-described fault detecting device is the same as the principle of detecting the fault by the above-described fault detecting device, and details are not described herein.

The detection method provided by the invention realizes the fault detection of a plurality of fans and indicates the faulty fan through the warning light, and the entire detection processing circuit outputs a detection signal. In addition, the method can effectively protect the fan and the processing circuit when the fan is reversely connected, and improve the anti-interference ability of the fault detecting circuit.

One of ordinary skill in the art will appreciate that all or a portion of the steps above may be accomplished by a program to instruct the associated hardware, such as a read-only memory, a magnetic disk, or an optical disk. Alternatively, all or part of the steps of the above embodiments may also be implemented using one or more integrated circuits. Correspondingly, each module/unit in the above embodiment may be implemented in the form of hardware or in the form of a software function module. The invention is not limited to any specific form of combination of hardware and software.

It is a matter of course that the invention may be embodied in various other modifications, equivalents, modifications and improvements within the spirit and scope of the invention. It is intended to be within the scope of the appended claims.

INDUSTRIAL APPLICABILITY A fault detecting device for a DC fan with an alarm output proposed by the present invention employs a multi-channel shared fault detecting circuit, which can simultaneously detect faults of a plurality of fans and indicate faults through warning lights. The fan makes it easy and quick to find the faulty fan. In addition, the device not only realizes the detection and processing of the alarm signal when multiple DC fans are in place, open circuit, blocked or reversed, but also realizes the fan and the detection circuit when the fan is reversely connected. The effective protection improves the anti-interference ability of the fault detection circuit, making the fault detection more reliable and accurate.

Claims

Claim

1. A fault detecting device for a DC fan having an alarm output, the device comprising a plurality of parallel fan fault detecting circuits and a signal processing unit, wherein all fan fault detecting circuits are connected to an input end of the signal processing unit, wherein each fan One end of the first current limiting resistor in the fault detecting circuit is connected to the power source, and the other end of the first current limiting resistor is connected to the input end of the signal processing unit and the alarm signal of the fan.

2. The apparatus according to claim 1, wherein

Each of the fan fault detection circuits further includes a light emitting diode and a second current limiting resistor, one end of the first current limiting resistor is connected to the power source, and the other end is connected to the alarm signal of the fan and the light emitting diode The anode of the light emitting diode is connected to one end of the second current limiting resistor, and the other end of the second current limiting resistor is connected to an input end of the signal processing unit.

3. The apparatus according to claim 1 or 2, wherein

The signal processing unit is implemented by an optocoupler or a triode.

4. The apparatus according to claim 2, wherein

When the signal processing unit is implemented by an optocoupler, one end of the second current limiting resistor is connected to the input end of the primary side of the optocoupler, the output end of the optocoupler primary side is grounded, and the input end of the optocoupler secondary side is connected to the power source. The output end of the optocoupler secondary side outputs a detection signal, and the output terminal is grounded through a pull-down resistor.

5. The apparatus according to claim 2, wherein

6. The device according to claim 2, 4 or 5, wherein

7. The device according to claim 2, 4 or 5, wherein

The resistance values of the first current limiting resistors in the different fan fault detecting circuits are the same or different.

8. The apparatus according to claim 2, 4 or 5, wherein The resistance values of the second current limiting resistors in the different fan fault detecting circuits are the same or different.

The method for detecting a fault of a DC fan having an alarm output of a fault detecting device for a DC fan with an alarm output according to any one of claims 2-8, wherein the method comprises: determining an LED indicator If it is on, if the LED indicator is on, it is determined that the fan is faulty. If the LED indicator is off, it is determined that the fan is normal.

The method of claim 9, wherein after the step of determining that the fan is faulty, the method further comprises:

The faulty fan is indicated by an alarm signal.