JPH05134711A - Control unit for mass flow controller - Google Patents

Abstract

PURPOSE:To arrange a mass flow controller control unit in the neighborhood of a mass flow controller as a different conpact device from a device control system, to shorten the path of an analog signal, to enable the stable operation of the mass flow controller to be executed, to easily execute hard design, to unnecessitate control for A/D inputting and D/A outputting to the mass flow controller in the device control system and to easily develop software. CONSTITUTION:The mass flow controller control unit 11 is provided with an MPU substrate 15, an A/D conversion substrate 16, D/A conversion substrates 17 and 18 and serial I/O 28, the mass flow controller is connected with the A/D and D/A conversion substrates 16-18 and the device control system is connected by serial I/O 28 with a line. The transmission and reception of the analog signal with the mass flow controller is executed with the substrates 16-18 and those with the device control system is linked with data communication.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mass flow controller control unit that functions as a driver for a mass flow controller.

[0002]

2. Description of the Related Art A mass flow controller adjusts a mass flow rate in a fluid flow path of gas, liquid, etc., and is installed in a line for transporting material gas, chemical liquid, etc. in the field of semiconductor device manufacturing, for example. In such a production line, an apparatus control system that controls the entire process is installed, and the drive control of the mass flow controller also plays the role of the apparatus control system.

FIG. 4 schematically shows the internal structure of a conventional device control system. In this figure, reference numeral 1 is the device control system, which includes an MPU board 2, an A / D conversion board 3, D / A conversion boards 4 and 5, input / output boards 6 and 7, and a constant voltage power supply 8. It has a control function of the mass flow controller 9.

The MPU board 2 constitutes a CPU and is responsible for overall internal control. A plurality of mass flow controllers 9, 9, ... Can be connected to the A / D conversion board 3, and these mass flow controllers 9, 9 ,.
The analog data signal from is converted into a digital data signal and transmitted to the MPU board 2. The MPU board 2 receives the mass flow controllers 9, 9, ...
Monitor the operating state of.

The MPU board 2 has a function of generating a digital control signal for driving and controlling each of the mass flow controllers 9, 9, ... One by one, and the digital control signal is supplied by the D / A conversion boards 4, 5. An analog signal for the mass flow controller is converted and given to each mass flow controller 9, 9, ....

In addition, the input / output boards 6 and 7 serve as interfaces with other controlled objects. The constant voltage power supply 8 supplies a power supply voltage to internal components.

With the above-described system, the mass flow controller is controlled by the device control system together with other devices arranged in the process, and operates in a state closely related to the other devices. ..

[0008]

By the way, in the conventional mass flow control system described above, a wiring cable is used to connect each mass flow controller to the device control system. However, since the mass flow controller handles an analog signal, the wiring thereof is performed. It is necessary to consider so as to avoid signal deterioration due to wiring resistance as much as possible in the design of.

However, the above-mentioned device control system is generally large in size, and because it cannot be installed in the vicinity of the mass flow controller in most cases in relation to maintenance and maintenance, the surrounding environment, etc., the cable becomes inevitably long and the electrical equipment hardware is inevitable. It creates a big constraint in design.

Further, since the device control system not only takes control of a large number of mass flow controllers at once, but also controls them in relation to other devices, it is complicated due to A / D input and D / A output. Data processing is required. Therefore, a lot of time and labor is spent in developing the device control program.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to control a mass flow controller which contributes to reduction of labor in both hardware and software development of a mass flow control system. To provide a unit.

[0012]

A mass flow controller control unit according to the present invention is a mass flow controller connection A / D converter for converting an analog data signal from one or more mass flow controllers into a digital data signal. Circuit, a D / A conversion circuit for connecting a mass flow controller, which converts a digital control signal for controlling drive of the one or more mass flow controllers into an analog control signal and gives the analog control signal, and the A / D conversion circuit And a communication control unit for receiving the digital control signal from the digital communication path and giving it to the D / A conversion circuit.

A mass flow controller control unit according to a second aspect of the present invention is an A / D converter for connecting a flow meter for converting an analog data signal from a flow path state indicator and a flow meter arranged in a fluid flow path into a digital data signal. Based on the contents of the digital data signal from the circuit and the A / D conversion circuit for connecting the mass flow controller and the A / D conversion circuit for connecting the flowmeter, the effective value of the flow rate in the fluid flow path is obtained and used as a flow path status indicator. And a display control unit for monitoring.

A mass flow controller control unit according to a third aspect of the present invention includes a display having a data display function for one mass flow controller and functioning as a flow path state indicator, and an operation section for performing a display switching operation. In response to the display switching command, a switching command generating unit that gives a switching command to the display control unit to switch and display the display content on the display for each mass flow controller.

A mass flow controller control unit according to a fourth aspect of the present invention provides a fluid flow based on an alarm device and a digital data signal from the mass flow controller connection A / D conversion circuit and the flow meter connection A / D conversion circuit. And a flow path monitoring unit that activates an alarm device when there is an abnormality in the result of checking the condition of the road.

A mass flow controller control unit according to a fifth aspect of the present invention comprises a communication control section for sending out the check result of the flow path monitoring section to the digital communication path.

[0017]

The present invention has a digital communication function with respect to a digital signal corresponding to an analog signal that is transmitted to and received from a mass flow controller, so that it can be connected to the device control system through a digital communication path and can be a compact separate device. Since it can be placed in the vicinity of the mass flow controller, it is possible to shorten the path of the analog signal that communicates with the mass flow controller, and the stable operation of the mass flow controller can be achieved accordingly.
Makes electrical hardware design easier.

The present invention also provides an A / D input and a D / A for a mass flow controller in an apparatus control system.
Since it is not necessary to control for output, software development becomes easy.

According to the present invention as defined in claim 2,
Since it has a function to monitor the flow path condition, it enables the operator to visually monitor at the site near the mass flow controller, and can respond quickly to any abnormalities and prevent accidents from occurring. it can.

In particular, according to the present invention as set forth in claim 3, since the monitor means uses one having a display capability for one mass flow controller and the display contents are switched and displayed, the display device is used as a display. Is simple, and contributes to further downsizing of the unit housing.

Further, the present invention according to claim 4 has a function of notifying when an abnormality occurs in the state of the fluid flow path, so that the abnormality can be surely dealt with even if it is not always monitored. Is possible.

Further, by referring to the monitor of the flow path state, it is possible to take more accurate measures.

Further, according to the present invention of claim 5, since the check result in the flow path monitor can be sent to the digital communication path, there is no problem in the data processing in the conventional device control system. ..

[0024]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an internal configuration of a mass flow controller control unit (hereinafter referred to as MC control unit) according to an embodiment of the present invention, and FIG. 2 shows a connection mode with other devices. ..

In these figures, the numeral 11 indicates the MC control unit of the present invention. The MC control unit 11 can be connected to a plurality of mass flow controllers 12, 12, ... As shown in FIG.
, 13, ... Can be connected to and receive signals from them. An apparatus control system 14 is connected to the MC control unit 11 of the present invention via a digital serial communication line. The casing of the MC control unit 11 is formed of, for example, a stationary box,
AC100V power cable, mass flow controller connection connector, and flow meter connection connector, which will be described later, total 9
One and one communication connector are provided and can be installed near the mass flow controller 12.

As shown in FIG. 1, the MC control unit 11
Is one MPU board 15 and one A / D conversion board 16
And two D / A conversion boards 17 and 18, a mass flow controller connection terminal 19, a flow meter connection terminal 20 and one LC
The D display driver substrate 21, the LCD display 22, the constant voltage source 23, the READY monitor 24, the buzzer 25, the buzzer reset switch 26, the data changeover switch 27, and the serial I / O port 28 are provided, and the substrates 15 to 18, 2 are provided.
The ones are connected by a bus line.

The MPU board 15 is positioned as a CPU of this unit and controls overall internal control, and its functional details will be described later.

A / D conversion board 16 and D / A conversion board 1
7 and 18 are a mass flow controller 12 and a flow meter 13
Is an interface with the unit 11. That is, the A / D conversion board 16 has 9 channels of analog inputs of 0V to 5V, and the mass flow controller 1
2 and the analog data signals from the flowmeter 13 are converted into digital data signals and transmitted to the MPU board 15. Each of the D / A conversion boards 17 and 18 has an analog output of 0V to 5V, 3 channels for each 3 channels in total, and indicates a mass flow rate set value from the MPU board 15 and a soot control signal to the mass flow controller 12. The digital signal is converted into an analog control signal and given to each mass flow controller 12.

Here, six mass flow controllers 12 and flowmeters 13 are connected to the A / D conversion board 16, and three mass flow controllers 12 are connected to each of the D / A conversion boards 17 and 18, and the six mass flow controllers 12 are provided. Are connected. The connection terminals 19 are drawn out from those boards 16 to 18, and the connection terminals 20 are the A / D conversion boards 16
It was drawn from.

The LCD display driver board 21 is an MPU.
The LCD display 22 is driven and controlled based on the display data from the substrate 15.
It is supposed to have a display capacity of 6 digits x 2 lines. The constant voltage power supply 23 supplies power to the internal circuit, the mass flow controller 12 and the flow meter 13, and the AC 100
V It has a plug into a commercial power outlet. RE
The ADY monitor 24 is for illuminating, for example, an LED when the MPU board 15 is in the communication OK state, and monitors the state. The buzzer 25 is for sounding an alarm and a buzzer when the flow rate in the fluid flow path system to be processed by the mass flow controller 12 or the flow meter 13 changes abnormally. The buzzer reset switch 26
This is for stopping the operating buzzer 25. The data changeover switch 27 is for changing the display content on the LCD display 22. Serial I
The / O port 28 is the main unit 11 and the device control system 1
A communication line connecting with 4 is connected.

Next, the operation of this embodiment constructed as described above will be described with reference to FIG. First, the device control system 14 transmits an inquiry to start setting data transmission. This inquiry is received by the MPU board 15. Then, the MPU board 15 confirms whether or not the reception preparation is completed, and if the preparation is completed, the reception preparation completion is returned. Upon receiving the completion of preparation, the device control system 14 transmits the set value of each mass flow controller 12 and the set value of the effective upper and lower limits of each flow meter 13. Each setting data is received by the MPU board 15. As a result, the device control system 14 downloads the data to the MC control unit 11, and the MPU board 15 sends the received digital data to the D / A conversion boards 17 and 18, and after the digital data is converted into analog signals in each of them, It is given to the mass flow controller 19. At this time, MP
The U board 15 performs data processing necessary for D / A conversion output of the setting data of each mass flow controller 12, and outputs the data at a constant cycle. On the other hand, the MPU board 15 returns the effective value obtained from each mass flow controller 12 and the flow meter 13, uploads it to the device control system 14, and supplies the effective value to the LCD display driver 21. At this time, the MPU board 15 reads the sampling output from the A / D conversion board 20 at a constant cycle and performs data processing such as level conversion.

The LCD display driver 21 sends the received data to the LCD display 22 for monitoring. This L
The effective value abnormality displayed on the CD display 22 is updated in real time. In addition, the contents of the data displayed on the LCD display 22 can be sequentially switched and displayed by the data changeover switch 27. That is, when the operator operates the switch 27 with a button or the like, the MPU board 15 instructs the LCD display driver 21 to switch the channel to be displayed each time the MPU board 15 receives the switch 27. As a result, the LCD display driver 21 switches the display on the LCD display 22 to that of another channel. Therefore, the operator can select the channel he or she wants to watch.

At the same time, the MPU board 15 checks the effective value obtained based on the effective upper and lower limit values, and if there is an abnormality, activates the buzzer 25 and sounds an alarm.
When the buzzer reset switch 26 is turned on,
The MPU board 15 stops the operation of the buzzer 25.

Therefore, the MC control unit 11 of this embodiment
According to the above, it is possible to dispose the device in the vicinity of the mass flow controller 12, which is compact and separate from the device control system 14 dedicated to the mass flow controller 2. Therefore, it is possible to shorten the path of the analog signal that communicates with the mass flow controller 12, that is, the analog signal path between the A / D conversion board 16 and the D / A conversion boards 17, 18 and the mass flow controller 12. In addition, the operation of the mass flow controller 12 can be stabilized, and the electrical hardware can be easily designed.

Further, since it is not necessary for the device control system 14 to perform control for A / D input and D / A output to the mass flow controller 12, software development is facilitated.

Further, since the LCD display 22 has a function of monitoring the flow path state, it is possible to visually monitor an operator at the site near the mass flow controller 12 and promptly respond to an abnormality. ..

In particular, according to this embodiment, the LCD display 2
2 shows that the channels of the mass flow controller 12 are switched and displayed one by one.
The CD display 22 may be a simple one, and the unit 1
This contributes to further downsizing of the first housing.

Furthermore, when an abnormality occurs in the state of the fluid flow path, an alarm is issued by operating the buzzer 25. Therefore, even if the abnormality is not always monitored, it is possible to reliably deal with the abnormality occurrence. It is possible.

Further, by referring to the monitor of the flow path state by the LCD display 22 described above, more accurate correspondence can be made.

Furthermore, since the effective value check result in the MPU board 15 can be sent to the device control system 14, there is no problem in the data processing that has been performed in the device control system.

[0042]

As described above, according to the present invention, since it has a digital communication function with respect to a digital signal corresponding to an analog signal transmitted / received to / from a mass flow controller, it has a digital communication path with the device control system. Since it is possible to connect it in the vicinity of the mass flow controller as a compact separate device,
It is possible to shorten the path of the analog signal that is exchanged with the mass flow controller, which enables stable operation of the mass flow controller, and facilitates the electrical hardware design.

According to the present invention, the A / D input to the mass flow controller in the device control system,
Since it is not necessary to perform control for D / A output, software development can be facilitated.

As a result, the mass flow controller control system can be constructed with a commercially available personal computer equipped with a serial I / O port.

According to the present invention as defined in claim 2,
Since it has a function to monitor the flow path condition, it enables the operator to visually monitor at the site near the mass flow controller, and can respond quickly to any abnormalities and prevent accidents from occurring. it can.

In particular, according to the present invention as set forth in claim 3, since the monitor means uses one having a display capability for one mass flow controller and the display contents are switched and displayed, the display device is used as a display. Is simple, and contributes to further downsizing of the unit housing.

Further, according to the invention of claim 4,
When an abnormality occurs in the state of the fluid flow path, it has a function of notifying the abnormality, so that it is possible to reliably deal with the abnormality even if it is not always monitored.

Further, by referring to the monitor of the flow path state, it is possible to take more accurate measures.

Furthermore, according to the present invention as defined in claim 5, since the check result in the flow path monitoring section can be sent to the digital communication path, there is no problem in the data processing in the conventional apparatus control system. ..

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a mass flow controller control unit according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a connection mode between the mass flow controller control unit shown in FIG. 1, the mass flow controller, and the device control system.

3 is a cycle diagram for explaining the operation of the mass flow controller control unit shown in FIG.

FIG. 4 is a block diagram showing a configuration of a conventional mass flow controller control unit.

[Explanation of symbols]

 11 Mass Flow Controller Control Unit 12 Mass Flow Controller 13 Flow Meter 14 Device Control System 15 MPU Board 16 A / D Conversion Board 17, 18 D / A Conversion Board 19 Mass Flow Controller Connection Connector 20 Flow Meter Connection Connector 21 LCD Display Driver 22 LCD display 25 Buzzer alarm 26 Buzzer reset switch 27 Data changeover switch 28 Serial I / O port

Claims (5)

[Claims] 1. An A / D conversion circuit for connecting a mass flow controller, which converts an analog data signal from one or more mass flow controllers into a digital data signal, and a digital circuit for drive controlling the one or more mass flow controllers. A D / A conversion circuit for connecting a mass flow controller, which converts a control signal into an analog control signal and gives it to the mass flow controller, and outputs the output of the A / D conversion circuit for connecting the mass flow controller to a digital communication path and the digital control signal. A mass flow controller control unit including a communication control unit that receives the signal from the digital communication path and supplies the D / A conversion circuit for connecting to the mass flow controller. 2. A flow path state indicator, a flow meter connection A / D conversion circuit for converting an analog data signal from a flow meter arranged in a fluid flow path into a digital data signal, and a mass flow controller connection A / D And a display control unit for obtaining a flow rate effective value in the fluid flow channel based on the contents of the digital data signal from the D conversion circuit and the A / D conversion circuit for connecting the flow meter and monitoring the flow rate effective value on the flow channel status display. The mass flow controller control unit according to claim 1, which is provided. 3. A display which has a data display function for one mass flow controller and which functions as a flow path state indicator, an operation section for performing a display switching operation, and a display unit in the display in response to the display switching command. The mass flow controller control unit according to claim 2, further comprising: a switching command generation unit that gives a display control unit a switching command to switch and display the display content for each mass flow controller. 4. The state of the fluid flow path is checked based on the digital data signals from the alarm device, the mass flow controller connection A / D conversion circuit and the flow meter connection A / D conversion circuit, and the result is abnormal. The mass flow controller control unit according to any one of claims 1 to 3, further comprising: a flow path monitoring unit that sometimes activates an alarm device. 5. A communication control section for transmitting the check result of the flow path monitoring section to a digital communication path.
The described mass flow controller control unit.