WO2005055062A1

WO2005055062A1 - Auto controlling system based on monitoring circuit of hardware of computer

Info

Publication number: WO2005055062A1
Application number: PCT/CN2004/001422
Authority: WO
Inventors: Cheng Li
Original assignee: Li, Qian
Priority date: 2003-12-08
Filing date: 2004-12-06
Publication date: 2005-06-16

Abstract

The present invention relates to an auto-controlling system based on monitoring circuit of hardware of computer, which is comprised of a computer, an executor, a controlled object and a sensor. On the motherboard of the computer, there is a monitoring circuit of hardware of computer, which has the integrated circuit chip as the kernel, in which the integrated circuit chip is programmable and has an internal bus. The monitoring circuit has an input port of fan speed count and a output port of fan PWM speed control. The output port of fan speed control is connected to the input of the executor. The output of the sensor is connected to input port of fan speed count. The system can use the monitoring circuit of hardware of computer on the motherboard as a controller and provide a control algorithm. The controlling system of the invention can achieve the purpose for monitoring and controlling more extensive controlled objects.

Description

Automatic control system based on computer hardware monitoring circuit

The present invention relates to a control system in a personal computer or a computer server (hereinafter collectively referred to as a computer), and particularly to a computer having a hardware monitoring circuit, a fan speed counting input port and a PWM fan speed control output port on a motherboard. Background technique

We know that an automatic control system includes the following basic parts: the controlled object, the sensor (transmitter), the controller, and the actuator.

At present, the development of computer technology is changing with each passing day, in which the frequency and integration of central processing units (CPU) and integrated circuits are constantly improving, so a large amount of heat will be generated, which will increase the temperature of the device and the inside of the computer case. Fans are often used for ventilation and heat dissipation. Most computer motherboards have hardware monitoring circuits to monitor and control the computer's operating conditions in real time, such as monitoring CPU fans, CPU temperature, chassis fans, and chassis temperatures. In these monitoring circuits, pulse width modulation (PWM) and automatic control technology are widely used. During computer operation, the hardware monitoring circuit automatically adjusts the fan speed according to the temperature of the component under test or the fan speed signal. The computer uses a smart fan (Smart fan ) Technology, the computer hardware monitoring circuit will control the fan to rotate according to the set temperature or set speed to dissipate heat to the computer components. When the temperature drops or the speed is too high, the fan speed will automatically decrease. When the temperature rises or the speed is low, the wind speed will automatically rise. The purpose is to reduce fan noise, save power usage, extend fan life, and ensure efficient system operation.

Generally, an integrated circuit (IC) chip of a computer hardware monitoring circuit provides 2 to 8 fan speed count input ports and 2-4 fan speed control output ports. These fan I / O ports Its monitoring circuit has a unique purpose. It is only used to connect a DC fan to the motherboard of the computer. It cannot be connected to other monitoring and control systems, and often has more than one I / O redundant wind. The fan port is the idle resource of the computer.

In the existing computer, although the manufacturers and CPUs have different main frequencies, and the computer cooling fans have different shapes and speeds, the electrical parameters of the fan interface on the computer motherboard are commonly observed by all manufacturers.

For 3-pin fans, the names and parameters of 3-pin fan connectors are shown in Table 1. In Table 1, plug 2 is the positive pole of the power supply. It provides + 12V _MAX working power for the DC fan. When controlling the fan speed, the voltage can be changed by adjusting the PWM duty cycle. Plug 3 is the common ground (G). Plug 1 is the fan speed. The fast and slow feedback signal input terminal. For a fan with a speed measurement function, the fan releases two pulse signals every one rotation of the fan (the following are based on analysis), and the computer hardware monitoring circuit will calculate the fan's rotation speed accordingly.

Table 1

The data and actual measurements provided by the computer and fan manufacturers show that the pulse waveform of the fan speed signal is a rectangular wave, and the frequency f of the signal of the rectangular wave has a linear relationship with the speed N. See Figure 1, which shows the fan speed pulse and the period T. Correlatively, the number of pulses occurring in a unit time can be measured to obtain the speed value:

Cycle T = tl + t2 Speed N = 60 ÷ (2 X T) (rev / min)

The relationship between the frequency f and the period is: f = l / T, the unit of f is hertz (Hz), and the unit of T is second.

(S),

Result: N = 30 X f (rev / min) Formula 1

Generally, when the number of pulses generated by one rotation of the fan is n, the rotation speed is N = 60 ÷ n X f, n = 2, 3, 4 and so on. The high level V of the output signal in Figure 1. _h , that is, the voltage amplitude is determined by the motherboard circuit, and the low-level V of the output signal is determined by the built-in speed measurement signal circuit of the fan. The principle is shown in Figure 2. The output of the built-in speed measurement signal circuit of the fan adopts an open-collector type, and an external pull-up load is provided. ,

When Q is on, 1 = 10 mA _max output voltage ν _ω = 0.4 volt (typical value); When Q is turned off, I 0 mA _min outputs the voltage V. _h = E. (Main board monitoring circuit working voltage). Because output V. It takes the power of the main board monitoring circuit, so the fan speed signal generation circuit automatically adapts to the working voltage of the motherboard chip. The fan speed can be seen in the computer's basic input and output system (BIOS), and it can also be monitored by the application software (program) under the operating system. Fan speed, BIOS and applications can display and control according to different values of fan speed input.

In the input channel of the computer application system, the analog voltage (current) output by the sensor must be converted by the A / D converter before being sent to the computer for processing. One of the methods of A / D conversion is the voltage / frequency (V / F) conversion method. V / F conversion is to convert the analog signal into a frequency signal and then send it to the computer. Although the response speed of the frequency measurement is slow, the V / F conversion The characteristics are good accuracy and linearity, low price, and the frequency measurement itself makes a counting process, which can be directly input to the I / O port of the interface circuit, or the timer / counter port when the level requirements are met.

The counting and calculation of the computer speed feedback signal are completed by a hardware monitoring circuit, which is composed of a programmable integrated circuit as the core. Hardware monitoring circuits mostly use highly integrated integrated circuits such as W83782D. W83637HF, ADM1031, etc. The common basic characteristics of these chips are: (1). All are programmable devices with internal bus integrated circuit chips, (2). Adjust the duty cycle to control the fan speed. (3). Both provide fan speed counting and temperature measurement input channels. The discussion and examples in this article are described by W83637HF. This series of products has a wide range of applications in the market, which are typical and representative. The function of the hardware monitoring circuit mainly completes the setting of temperature and rotation speed, the setting of the adjustment interval, the detection of temperature and rotation speed, and the formation and control calculation of temperature and rotation speed deviation. W83637HF is a general-purpose interface circuit that provides input and output device connections, with driver interfaces, serial interfaces, parallel interfaces, keyboard and mouse interfaces, infrared ports, smart card interfaces, system power management, and more. The main functions related to this article are the computer hardware status monitoring provided by W83637HF, which can measure multiple sets of computer system parameters, such as operating voltage, fan speed, and CPU temperature. W83637HF supports Smart fan control system, including two automatic modes: Thermal Cruise and Speed Cruise. W83637HF's main performance (list only relevant parts of this article):

W83637HF is a programmable device with a clock frequency of 24 or 48MHZ;

Support LPC internal bus; ' 3-way temperature measurement, support thermistor, diode and CPU built-in PN junction measurement; built-in 8-bit A / D converter;

5 voltage monitoring (+ 5V, +3. 3V, Vcoro, Vbai :, + 5VSB);

40-terminal programmable universal input / output port;

3-way fan speed counting;

3-way fan speed control;

Over-temperature output interrupt signal οντ # _;

System management interrupt signal SMI #;

Programmable interrupt protection signal is enabled / disabled;

Program the setting value and interval of all monitoring parameters;

Support application software to measure computer system monitoring parameters (Intel, Acer, Winbond and other company programs);

With automatic detection of power supply voltage sound;

Comply with Microsofe Computer 2000 / Computer 2001 Hardware Design Guide;

Support ACPI and DPM power management;

On-chip 8-bit register and bus configuration;

128-pin package.

The hardware monitoring circuit has a fan speed control function. The fan speed is controlled by adjusting the fan working voltage. The fan working voltage is adjusted by adjusting the PWM duty cycle. The circuit output voltage has a linear relationship with the PWM duty cycle. The output voltage:

XPWM Duty cycle type 5

The PWM output is smoothed and filtered to become an analog voltage. The PWM duty cycle is adjusted so that the swing (adjustment range) of the output voltage is 0-12 volts (for a 12V DC power supply), which is essentially a digital-to-analog converter. W83637HF provides three fan speed control based on pulse width modulation. The duty cycle of pulse width can be controlled by program. The default duty cycle is 100%, corresponding to 12V output voltage. Fans without speed regulation will run in this state. . The schematic diagram of the PWM application circuit is shown in Figure 3. The circuit includes the PWM control signal input, filtering, isolation amplification and output drive. Usually, the computer fan port can output current. Io = 300 ^ 1000mA, can directly drive relays and other actuators. Notebook computer fan port can output current Io = 150mA (typical value).

There are also voltage levels such as DC + 5V, + 24V, + 48V in the circuits in different computers and electronic equipment. The above analysis results are also applicable.

The computer hardware monitoring circuit has a smart fan automatic control system. There are two types of smart fan automatic control system according to the system composition and the return signal is temperature or speed. One is a thermal cruise automatic control system, the other is One is the Speed Cruise automatic control system. In the temperature patrol mode, there are three channels of temperature / PWM voltage control: system temperature / PWM1 voltage control, CPU temperature / PWM2 voltage control, chassis temperature / PWM3 voltage control, and PWM voltage control is output through the fan speed control terminal. The smart fan automatic control system provided by the integrated circuit W83637HF can automatically control the fan speed according to the set temperature, keeping the temperature within the set temperature range. Set the temperature and temperature allowable range (for example, 55 ± 3 degrees) through the BIOS. As long as the temperature is within the set range during operation, the fan is stopped. Once the temperature exceeds the upper limit of the set temperature (58 degrees), the fan will turn on. It starts at a set speed, and then the hardware monitoring circuit automatically controls the PWM duty cycle to change the fan voltage and adjust the fan speed according to the change in temperature. The following three cases are discussed with reference to Figure 5:

(1) If the temperature still exceeds the upper limit setting T (for example: 58 degrees), the duty cycle of PLi will slowly increase. If the fan is already running at the maximum speed (the maximum duty cycle), and the temperature still exceeds the set upper limit ( (For example, 58 degrees), the system will generate a warning message to protect the computer system.

(2) If the temperature is below the set upper limit (for example, 58 degrees), but above the set lower limit (for example, 52 degrees), the fan speed will remain at the current speed, as long as the temperature is within the set range (52 A 58 degrees) are all the same.

(3) If the temperature is below the set lower limit (for example, 52 degrees), the PWM duty cycle will slowly decrease until the speed is zero. As long as the temperature is below 52 degrees, the fan will not run.

In the fan speed patrol mode, the system provides three channels of speed / PWM voltage control: fan speed 1 / PWM1 voltage control, fan speed 2 / PWM2 voltage control, fan speed 3 / PWM3 voltage control, and the fan speed is passed through the fan speed counting terminal. Enter. W83637HF according to the preset speed set (Common speed factor Count is used for convenience analysis. The relationship between Count and speed is shown in Equation 6.) Control the fan speed to make the fan speed run within a certain interval. Set the required fan speed factor Count (set speed) through the BIOS, for example, set Count to 160 ± 10, as long as the fan speed is within the set range, the output PWM duty cycle will remain unchanged, and the fan operating voltage will not If the current fan speed factor is higher than the set upper limit, such as 160 + 10, the PWM duty cycle will increase and the output voltage will increase to keep the speed factor less than the set upper limit. In another case, if the current fan speed constant is low When the lower limit is set to 160-10, the duty cycle of PLi will decrease and the output voltage will decrease to keep the speed factor above the lower limit.

In the temperature patrol and speed patrol system, the instructions of the hardware monitoring circuit W87637HF are accepted. Therefore, the hardware monitoring circuit W87637HF is the actual controller and the core of the control system.

The structure diagram of the computer in the temperature patrol mode is shown in Figure 8, except that the feedback link in the figure uses A / D in the monitoring circuit instead of T / F: At this time, a semiconductor temperature sensor is used, and the sensor output is sent to the computer monitoring circuit. It is an analog signal, which is converted into a digital signal by the A / D converter in the monitoring circuit. The hardware monitoring circuit W83637HF functions as a controller, compares the measurement signal sent by the temperature sensor with the set temperature, obtains the deviation signal, and calculates it according to a pre-designed control algorithm, and then adjusts the P duty cycle. The output voltage signal, the fan plays the role of an actuator, the object being adjusted is the computer part. In this operating mode, the temperature of the computer part determines the size of the fan speed. This is a closed-loop control system. Summary of the invention

The technical problem to be solved by the present invention is to provide a composition method of a monitoring and control system based on a computer hardware monitoring circuit, which can utilize the resources of an existing computer to a greater extent, and can monitor and control a wider range of controlled objects.

The technical solutions adopted by the present invention to solve the above technical problems are:

The invention consists of a computer, an actuator, a controlled object, and a sensor, which is a closed-loop automatic control system. It uses a hardware monitoring circuit on the computer's main board as a controller; it uses a P medical and amplifier circuit integrated on the monitoring circuit to complete digital / analog (D / A) conversion, using fan output channel as actuator output channel; The feedback signal is input to the hardware monitoring circuit by the fan speed counting terminal. The fan speed counting input channel is used as the feedback signal channel. The controlled parameter output by the sensor is converted into a frequency signal by a parameter / frequency converter to complete the analog / digital (A / D). Conversion; The controlled object and parameter sensor can be controlled objects and parameter sensors inside or outside the computer, and the established method provided by the computer can be used to set the adjusted parameter setting and allowable interval through the basic input output system (BIOS). Can use computer CPU as controller through internal bus (such as LPC, ISA, Smbus (I2C)), use application software to control and complete monitoring. '

The beneficial effects of the present invention are: make full use of the existing hardware and software resources of the computer, change the dedicated speed signal measurement channel into a multi-purpose signal measurement channel, and expand the dedicated fan output channel into an output channel that can use multiple actuators , Evolving a dedicated speed control system into a multi-purpose measurement and closed-loop control system.

The invention has a simple structure (compared to using a computer PCI slot for input / output signals), plug and play, no driver required, and can run in a state that does not occupy a CPU and no operating system applications. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is the pulse waveform diagram of the speed measuring fan;

Figure 2 is a schematic diagram of the connection between the speed measuring fan and the computer motherboard;

Figure 3 is a schematic diagram of the PWM control circuit of the monitoring circuit;

Figure 4 is the connection diagram of fan socket with SSR, load and feedback signal;

Figure 5 is the temperature control curve of the PWM control signal and the temperature of the object being adjusted in the temperature patrol mode; Figure 6 is the PWM control signal and the speed curve of the fan in the speed patrol mode;

FIG. 7 is a block diagram of an existing computer system speed tour ring;

Figure 8 is a block diagram of the control system when the computer system uses a T / F converter;

FIG. 9 is a block diagram of a control system according to Embodiment 1 of the present invention;

Figure 10 is a block diagram of the control system when the computer system controls external objects;

11 is a circuit diagram of a temperature / frequency converter according to an embodiment;

FIG. 12 is a schematic diagram of liquid level control according to the second embodiment of the present invention. detailed description

Example of feedback measurement channel: In this embodiment, the rotational speed signal measurement channel is used to measure the temperature, and the output signal of the temperature / frequency (T / F) converter is used to replace the fan's rotational speed feedback signal. The circuit diagram of the T / F converter is shown in Figure 11. The working principle of T / F conversion is as follows. In Figure 11, LM35 is used as a temperature sensor. LM35 is a high-precision integrated circuit temperature sensor. LM35 integrates the driving circuit, signal processing circuit and necessary logic control circuit on a single chip IC. It is easy to use and small in size. The output voltage of the sensor has a linear relationship with the change in temperature. Its main characteristics are: When the temperature changes from 50 ° C to + 150 ° C, it can change linearly at 10mV / ° C. 5V The output voltage is proportional to the Celsius temperature to achieve the temperature-to-voltage conversion. According to the single power connection of Figure 11, it can achieve a temperature measurement of 0 ~ + 150 ° C, and the corresponding output voltage is 0 ~ 1. 5V In the circuit, LM331 is a voltage / frequency (V / F) converter. LM331 as a voltage / frequency converter is a common circuit suitable for A / D converter. LM331 accepts the voltage signal of LM35 and converts the voltage into frequency. The signal is input from terminal 7 to a voltage of 0 to 1. 5V, which is converted by V / F of the LM331 into a frequency and sent to the subsequent computer monitoring circuit for counting. Here, the T / F conversion circuit performs two conversions, namely temperature / electricity. Voltage (T / V) conversion and voltage / frequency (V / F) conversion. According to the circuit structure shown in Figure 11, select the appropriate circuit parameters to fit the speed / frequency curve with the temperature / frequency curve. In the circuit, the role of R4 and adjustable potentiometer Rwl is to adjust the gain deviation of LM331 and the deviation caused by R2, R5 and C3. The size of R6 is adjusted according to the working voltage. It is adjusted to meet the 4N28 input current requirements.

Known output according to LM35 data:

V ₀ = (10mv / ° CX t) Equation 2

Output frequency according to LM331 data: f. _ut = (R4 + Rwl) Vi / (2. 09R2R5C3) Calculated according to the parameters in Figure 11: f. _ut = 256Vi formula 3

Substituting Equation 2 into: f. _ut = 2.56t Equation 4

-In this way, the temperature is input to the fan pulse counting terminal in the form of a frequency signal, and the T / F conversion is completed. When the input voltage is 0 ~ 1.5V, the output frequency is 0 ~ 384Hz. It can be seen that when the temperature of the entire circuit changes from 0 ~ 150 ° C, the number displayed by the computer is 0 ~ 11520 revolutions per minute corresponding to the count. Very convenient. When the temperature is 55 ± 3 degrees, the output frequency is 141 ± 9Hz and the (corresponding) speed is around 4219 rpm. These data will be used in Table 2 below.

In this embodiment, the fan interface of the computer motherboard is three pins, from which the control voltage and the frequency signal converted by the sensor are input. In order to reduce power supply interference, the 12V power supply of the circuit is obtained from the 12V power supply of the computer by an isolated DC / DC voltage converter or provided by the external circuit of the computer. In order to reduce channel interference, the frequency output of the LM331 is optically isolated, so that the T / F converter is not electrically connected to the computer. The output signal from the 3 terminals of the LM331 is transmitted to the measurement terminal of the speed feedback through the output of the optical coupler 4N28. Using a digital temperature sensor such as the TMP03 / 04 with a temperature / frequency converter, the circuit can be simplified.

The structure of the computer's speed patrol mode is shown in Figure 7. The hardware monitoring circuit W83637HF also functions as a controller. It adjusts the output voltage signal by adjusting the PWM duty cycle to control the fan speed. At the same time, the monitoring circuit accepts the fan speed feedback Signal, but there is no direct signal connection with the actual controlled object-computer components. In this mode of operation, the temperature of the cooling object has no exact relationship with the controller. The improvement method is to use the T / F conversion circuit shown in Figure 11 to form the feedback link according to the structure of Figure 8. Install a temperature measuring element such as LM35 on the surface of the computer component to convert the temperature signal into a frequency signal proportional to it. Input the feedback signal at the counting terminal to calculate the corresponding temperature, as shown in Equation 4. This structure has several advantages:

(1) The cooling object (the controlled object) has a signal connection with the computer hardware monitoring circuit (controller). The temperature of the cooling object (the controlled parameter) is related to the fan speed (actuator output) and forms a closed-loop regulation system.

(2) The sensor has good linearity and small error.

(3) The frequency signal is easy to transmit remotely, and it is easy to isolate.

(4) No A / D converter.

(5) The ready-made fan socket provided on the computer motherboard can be used as an interface for easy connection. At this time, the original speed tour ring has evolved into a universal closed-loop automatic control system. The analysis of Figure 5 above is also applicable to the situation at this time. Table 2 lists the corresponding relationship between the frequency, Count, and speed when the T / F conversion circuit is set at 55 ± 3 degrees. According to the speed factor Count corresponding to Table 2 Setpoint and allowable temperature range. Therefore, it can be seen that Count can correspond to any parameter converted into a frequency quantity, not just the speed.

Example of an open-loop control system: As shown in FIG. 4, the established driving circuit and interface (socket) of the hardware monitoring circuit on the computer motherboard are used. The input (control) circuit of the SSR is used to connect the working power terminal of the PWM fan socket on the computer motherboard. With this voltage signal as the control signal of the relay, the SSR output (controlled) circuit is connected in series with the load, the load is powered by 110V AC, and the load is an AC fan of the computer power supply. Obviously the relay can also use an electromagnetic relay.

In this way, it is possible to control both DC fans of different voltage levels and higher-power AC fans or other actuators such as valves and motors. As long as DC power or AC power is used in the relay output circuit, pay attention to the action required by the load The direction selection relay is normally open (contact) or normally closed (contact).

Example 1 of the closed-loop control system: The composition structure shown in FIG. 7 is adopted. The closed-loop control system based on the computer hardware monitoring circuit is an automatic temperature control system for computer components. It consists of a computer, an actuator, a solid state relay (SSR), a fan, The controlled object is composed of computer parts, a feedback sensor, a temperature sensor and a T / F. The motherboard of the computer uses a programmable device W83737HF (or other similar device) as the core to form a hardware monitoring circuit. The circuit has a fan speed counting input port. , PWM fan speed control output port and amplifier circuit. The system uses the hardware monitoring circuit on the computer motherboard as the controller. The output of the fan fan speed control is connected to the solid state relay (SSR) input. The fan is connected to the SSR. The temperature sensor is used to measure the temperature of the computer components. The signal from the temperature sensor passes the temperature. The frequency / frequency (T / F) converter outputs a frequency signal to complete the analog / digital (A / D) conversion of the input channel. The output of the temperature / frequency converter is connected to the fan speed counting input terminal.

The controlled parameter setting and allowable interval are set by the computer's basic input and output system. See Table 2 for the set temperature setting and allowable interval.

Table 2 is a comparison table of Count, speed, temperature, and input frequency. Count and speed in the table are calculated by the following formula 6, the frequency is calculated by the formula 1, and the temperature is calculated by the formula 4. Table 2 and the temperature column in the table will also be used later.

Table 2 Count-speed temperature frequency

1 170 3970 52 132

2 160 4219 55 141

The relationship between 3 150 4500 58 150 speed N and speed factor Count is given by the integrated circuit W83637HF specification:

N / 2 K / Count type 6

It can be seen that the speed factor Count is inversely proportional to N, and the default constant K = l. 35 X 10 2. A larger Count corresponds to a smaller NR. When Ν = 1000, the Count is 675. A smaller Count corresponds to a larger N. Set the speed count in the BIOS to 5 digits. When N = 99999, Count = 6.7.

In addition to the temperature requirements when the computer is working, there are other environmental requirements such as humidity, vibration, radiation, and air pressure according to different occasions. These quantities can be converted by the sensor or transmitter into electricity and then converted into frequency signals or using digital sensors It is converted into a frequency signal and measured by a computer speed input terminal to form a measurement and control system. In this way, you can use the alarm and interrupt signals set by the computer for the speed signal. For example, by measuring the humidity signal, an automatic humidity control system can be constructed to humidify or dehumidify.

In addition to working in the automatic control mode described above, the smart fan system can also work in the manual BIOS control mode. In addition, because the programmable integrated circuit of the hardware monitoring circuit has an internal bus connected to the CPU such as the LPC bus, ISA bus, and Smbus (I2C) bus, the monitoring circuit can also communicate with the CPU to exchange data. Many applications also do this, such as speedfan.exe and Intel (INTEL) LDCM software. In this case, use the CPU as the controller, write the control algorithm in the application program, use the speed signal measurement channel as the feedback signal measurement channel, and use the fan speed control output channel as The output channel of the actuator, connected to the controlled object can also form a closed-loop control system.

In addition to monitoring the internal parameters of the computer, according to the composition principle of the control system, it is also applicable to external process control of the computer to form a control system. As shown in Figure 10, it is further expanded. After SSR is connected to the actuator or the control valve, the controlled object can be production In the process, the controlled parameter signal is converted by the sensor at the same time, and then the V / F conversion is used to use the frequency signal as the final output for feedback. This forms a closed-loop control system. System. A control system, in addition to the above parts, is equipped with auxiliary devices. For example, given devices, display devices, conversion devices, etc., these are implemented on a computer through a keyboard, a display, and computer external devices.

Closed-loop control system Example 2: It is a closed-loop control system—an automatic control system for the tank liquid level. The schematic diagram of the system is shown in Figure 12. It consists of a computer—controller, actuator—SSR and electric control valve. Controlled object-a material tank, which consists of a level sensor and a V / F converter used to measure the level of the controlled object.

The SSR and V / F converter can be set in the computer case. The output of the liquid level sensor is connected to the input of the V / F converter. The output of the SSR controls the electric control valve. In the computer case, the Puli fan speed control output is connected to the SSR input; the V / F output is connected to the fan speed counting input port, as shown in Figure 10 to implement the system composition. If the height of the tank is 100mm, the liquid level in the tank is required to be 500mm ± 50mm to form a liquid level adjustment system, where qi represents the inflow of the material and q. Represents the outflow of materials, h represents the liquid level of the storage tank; hs represents the height of the liquid level of the storage tank required for production. The liquid level sensor sends the change of the liquid level in the tank (the controlled parameter) to the computer, and the computer hardware monitoring circuit W87637HF (controller) sends the adjusted parameter h and the given liquid level height hs from the liquid level sensor. (Predetermined signal) Make a comparison, and send a corresponding control signal according to the deviation signal obtained from the comparison, to control the opening of the inlet valve to change the amount of liquid inflow, so that the liquid level is maintained near a given value hs. Note that in this example, the actuator must be connected in a reaction mode. When the liquid level rises, the actuator moves to a small direction, and it can also be done by using sensor migration. .

If the tank liquid level sensor output corresponds to 0 ~ 5V (TlOOmm liquid level, then the sensor output: Vo = 5h, and by the circuit of Figure 11 and Equation 3,

Obtained: f = 1280h Equation 7

According to Equation 6 and Equation 1, the speed factor Count = K / N = K / 30f is used to calculate the Count value at different frequencies. Given Count and the allowed change interval, Count = 35 ± 4 is calculated. Enter the value through the BIOS, then The tank liquid level is 500 ± 50mm and the liquid level is automatically adjusted.

table 3

Count h (mm) f (Hz) 1 31 550 704 '

2 35 500 640

3 39 450 576 The closed-loop automatic adjustment system constructed according to Figure 10 is particularly suitable for constant value adjustment. As long as the corresponding frequency signal relationship between the sensor and the V / F converter is output, the corresponding speed factor Count and the allowable change interval are calculated. Adjust the parameters and allowable change intervals. List the table similar to Table 3 and key in the values through the BIOS. The controller's algorithm does not require ordinary users to enter. References:

1. http://www.national.com/, LM35.PDF

2. http: 〃 www, winbond.com, W83637HF.PDF

3. http://www.almice.com, SPEEDFAN.EXE

4. http: 〃 www.sunon.com

Claims

Rights request

1. A measurement system based on a computer hardware monitoring circuit. The computer hardware monitoring circuit is used to form a controller, and the signal output by the sensor is connected to the fan speed measurement input terminal of the monitoring circuit. It is characterized in that the sensor output channel is provided with There are parameter / frequency converters.

2. A closed-loop control system based on a computer hardware monitoring circuit. The system consists of a computer, actuator, controlled object, and sensor. The closed-loop control system is composed of a computer hardware monitoring circuit on the motherboard of the computer. The hardware monitoring circuit is programmable and internal. The bus integrated circuit chip is the core and has a fan speed counting input port and a fan pulse width modulation (Puli) speed control output port, which is characterized in that the output signal of the hardware monitoring circuit fan P hunting speed control output port is amplified to drive and execute The input connection constitutes the output digital / analog conversion channel. The sensor is used to measure the parameter of the controlled object. The signal output by the sensor is a frequency signal through the parameter / frequency converter. Its output is connected to the fan speed counting input port of the hardware monitoring circuit. The input analog / digital conversion channel is formed, and the hardware monitoring circuit is used as the controller.

3. An open-loop control system based on a computer hardware monitoring circuit. The computer hardware monitoring circuit is used to form a controller, and the hardware monitoring circuit fan pulse width modulation (PWM) speed control is used to adjust the circuit output, which is characterized in that the circuit output is amplified. After driving the relay, connect the load in the relay output circuit.

4. The open-loop control system according to claim 3, wherein the relay is an electromagnetic relay or a solid state relay (SSR), and the load is a fan.

5. The measurement or control system according to claim 1 or 2, wherein the parameter / frequency converter is a temperature / frequency converter or a level / frequency converter or a humidity / frequency converter.

6. The measurement or control system according to claim 1 or 2, characterized in that the value of the fan speed measurement has an exact correspondence (mathematical) relationship between the measurement and the parameters of the controlled object.

7. The measurement and control system according to claim 1, 2, and 3, characterized in that the calculation and control functions are completed in an integrated circuit chip of a computer hardware monitoring circuit.

8. The control system according to claim 2, wherein the controlled parameter setting value and allowable interval can be set through a computer's basic input and output system.

9. The measurement or control system according to claim 1, wherein the sensor is a digital sensor, and the sensor outputs a frequency signal.

10. The measurement and control system according to claim 1 or 2 or 3, characterized in that the monitoring circuit can communicate with and use the CPU of the computer through any of the internal buses LPC, ISA, Smbus (I2C) that are made available on it. Application software measurement or control.