JP2644742B2 - Composite transmitter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a controller for controlling a transmitter, an actuator, and the like for detecting a plant state such as temperature, pressure, and differential pressure.

[Conventional technology]

Transmitters and controllers are generally used as process control devices that control the operation of conventional processes, etc.
These transmitters are equipped with a sensor that detects temperature, pressure, differential pressure, flow rate, etc., and a converter that converts the output signal of the sensor into, for example, a unified electrical signal of 4 to 20 mA DC and outputs it. Transmitters, pressure transmitters, differential pressure transmitters, etc.

The controller compares the signals output from these transmitters with preset parameter values and outputs a signal for correcting the deviation to control an operating device such as a valve or an actuator.

Recently, a microcomputer has been used for both the transmitter and the controller.
As disclosed in Japanese Patent Application Laid-Open No. 85649 and Japanese Patent Application Laid-Open No. Sho 59-114930, there is a type in which a signal conversion section performs multi-item signal processing using a microprocessor. In the case of a controller, a distributed direct digital control (Direct Digital control, D) called a one-loop controller is used.
DC) is widespread.

FIG. 2 is a block diagram of a conventional transmitter using a microprocessor.

Reference numeral 1 denotes a composite sensor unit, in which a differential pressure sensor 2, a static pressure sensor 3, which detects the pressure of the plant, and a temperature sensor 4, which detects the temperature of the housing of the sensor unit, are housed.

Reference numeral 5 denotes a multiplexer which inputs signals from the differential pressure sensor 2, the static pressure sensor 3, and the temperature sensor 4 to perform signal processing. An input selector 6 selects an output signal of the multiplexer 5 based on an input selection signal Ex. 7 converts this output signal
A / D converter.

A microprocessor 8 compares the output signal of the A / D converter 7 with the correction coefficient value of the memory 9 and corrects the output signal of the differential pressure sensor 2. Reference numeral 10 denotes a D / A converter for converting the output of the microprocessor 8 into an analog signal. Reference numeral 11 denotes a production computer for writing a map of a temperature correction coefficient and a static pressure correction coefficient into the memory 7.

Reference numeral 12 denotes an input / output communication device for changing a measurement range, adjusting a zero point, setting a signal delay time, and the like.

In this transmitter, the microprocessor 8 is an A / D converter 7
And the correction coefficient value of the memory 9 are input and compared, and the output signal of the differential pressure sensor 2 is corrected for temperature and static pressure, and only the corrected differential pressure signal is D / A converted. enter the vessel 10, and converts this case the analog signal I ₀ of the 4 to 20mA DC.

The production computer 11 is used when manufacturing a transmitter, and the map of the temperature correction coefficient and the static pressure correction coefficient written in the memory 9 is specific to each transmitter.

FIG. 3 is a block diagram of a conventional controller using a microprocessor.

Reference numeral 13 denotes a multiplexer, which inputs signals E ₁ , E ₂ , and E ₃ to perform signal processing. 14 is an input selector, which is an input selection signal
Selecting a signal output to the A / D converter 15 from the multiplexer 13 by E _y. Reference numeral 16 denotes a microprocessor, which inputs an output signal of the A / D converter 15 and a set value of the memory 17 to perform an arithmetic operation, and inputs the output signal to the D / A converter 18. D / A converter
18 converts the output of the microprocessor 16 into an analog signal I _0.

In this controller, the microprocessor 16 is the A / D converter 1
Calculate based on the output of 5 and the set value set in the memory 17, and output the output signal by the D / A converter 18 to DC4 ~ 20.
This is output as a mA signal to control various operating devices.

[Problems to be solved by the invention]

As described above, the conventional transmitter outputs a signal using a microprocessor, but is used only for the purpose of obtaining an auxiliary signal for reducing the influence value of the temperature sensor and the static pressure sensor transmitter itself. Not.

That is, the temperature signal and static pressure signal obtained from the sensor are used to compensate the differential pressure transmitter,
As the output signal of the transmitter, only the signal related to the differential pressure is output as a unified analog signal DC4 to 20mA. In the case of performing the process control, the differential pressure transmitter,
The problem of separately requiring a pressure transmitter and a temperature transmitter remains.

In the case of a controller, the arithmetic processing of various signals is performed by a microprocessor, but the output signal of the above transmitter is used as an input signal. It will not change.

SUMMARY OF THE INVENTION An object of the present invention is to provide a composite transmitter that can use the functions of various conventional transmitters as a single unit and that can also function as a controller.

[Means for solving the problem]

The features of the present invention for achieving the above object are formed on a single chip, at least, a differential pressure detecting means for detecting a process differential pressure or a pressure difference, a static pressure detecting means for detecting a process static pressure, And a composite sensor unit having a temperature detecting unit for detecting a temperature in the housing in which the single chip is stored, and a storage unit for storing each correction coefficient value for correcting each detection signal from the composite sensor unit. In order to selectively capture the detection signal from the composite sensor unit and correct each detection signal with each of the captured detection signals, a correction calculation process of the detection signal is performed using the correction coefficient value of the storage unit. A digital operation unit for performing the operation, and an output unit for transmitting the operation result of the digital operation unit to the outside, wherein the temperature detection unit provided in the composite sensor unit; Separately, plant temperature detecting means for directly detecting the temperature state of the plant and outputting a detection signal to the digital operation means, a differential pressure signal in which static pressure and temperature are corrected, a static pressure signal in which temperature is corrected And arbitrarily selecting and outputting each signal of the temperature signal obtained by the plant temperature detecting means.

Still further, it is formed on a single chip, at least
A composite comprising: a differential pressure detecting means for detecting a process differential pressure or a pressure difference; a static pressure detecting means for detecting a static pressure of a process; and a temperature detecting means for detecting a temperature in a housing in which the single chip is stored. A sensor unit, storage means for storing each correction coefficient value for correcting each detection signal from the composite sensor unit, and selectively captures a detection signal from the composite sensor unit; Digital correction means for performing correction calculation processing of the detection signal using the correction coefficient value of the storage means for correcting each detection signal, and output means for transmitting the calculation result of the digital calculation means to the outside. In the composite transmitter, a temperature signal of the plant is directly detected and a detection signal is output to the digital operation means, separately from the temperature detection means provided in the composite sensor unit. Plant temperature detecting means, and parameter setting means for storing at least each parameter set value of a proportional parameter, a derivative parameter and an integral parameter, and inputting the parameter set value to the digital calculating means. In addition to the above-described correction calculation processing of each detected signal, a correction calculation using the above-described parameters is performed, and a differential pressure signal corrected in static pressure and temperature, a static pressure signal corrected in temperature, and the plant The purpose is to arbitrarily select and output each signal of the temperature signal obtained by the temperature detecting means.

[Action]

In the composite transmitter of the present invention, a temperature sensor formed in a composite sensor unit used in a conventional transmitter is used to detect the temperature of the transmitter itself, whereas a thermocouple or a thermometer is used. A plant temperature detecting unit for directly detecting the temperature of the plant by a resistance pair is provided, and this output signal is input to a microprocessor as digital operation means together with each output signal of the composite sensor unit. Correction calculation is performed on the output signal of the differential pressure sensor whose temperature has been corrected and the output signal of the static pressure sensor whose temperature has been corrected, and further, each set value such as a proportional parameter, an integral parameter and a differential parameter is stored. And a parameter setting means for inputting to the microprocessor, wherein corrected output signals of the differential pressure sensor and the static pressure sensor are provided. The detection signal of the plant temperature detection unit is added and the calculation is performed again by the microprocessor, and the calculation result is transmitted to the outside. Therefore, as an output signal, a differential pressure signal, a static pressure signal, and a temperature signal are provided as necessary. Can be selected and obtained, and one instrument can be used as a differential pressure transmitter, a pressure transmitter, and a temperature transmitter, and because of its configuration, it can be used as a controller. Thus, the functions of the transmitter and the controller can be unified, and the economy and reliability can be improved.

〔Example〕

 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of a composite transmitter according to the present invention, and the same parts as those in FIGS. 2 and 3 are denoted by the same reference numerals.

In the figure, reference numeral 19 denotes a multiplexer for inputting output signals of the differential pressure sensor 2, the static pressure sensor 3, and the temperature sensor 4 as in the case of FIG. Reference numeral 20 denotes a plant temperature detector, which uses a thermocouple or a resistance temperature detector and outputs an output signal to the multiplexer 19. 21 is an input selector selects the signal output from the multiplexer 19 to the A / D converter 22 by input select signal E _Z. 23 is a microprocessor, which is an A / D converter 22
A / A is compared with the output signal of
The sensor signal input to the D converter 22 is corrected. Reference numeral 25 denotes a parameter setting memory for storing parameter values such as a proportional parameter, an integral parameter, and a derivative parameter and inputting them to the microprocessor 23. 26 is a D / A converter that converts the output of the microprocessor 23 into an analog signal. 27
Is an input / output device for selecting an output signal of the D / A converter 26, and 28 is a production computer for writing a map of a temperature correction coefficient and a static pressure correction coefficient to the memory 24.

In the electronic transmitter and controller of this embodiment, the multiplexer 19 has a differential pressure sensor 2 for detecting the differential pressure of the plant.
, The output of the static pressure sensor 3 for detecting the pressure of the plant as the static pressure of the transmitter, and the output of the temperature sensor 4 for detecting the temperature of the main body of the transmitter. A plant temperature signal directly detected by a thermocouple or a resistance temperature detector is input from the unit 20.

Input selector 21 operates according to the input selection signal E _Z, sends a signal to the multiplexer 19. The multiplexer 19 inputs the output signal to the A / D converter 22 according to the signal. The microprocessor 23 compares the output signal of the differential pressure sensor 2, the output signal of the static pressure sensor 3 and the output signal of the temperature sensor 4 sequentially sent from the A / D converter 22 with the correction coefficient value of the memory 24. The output of the differential pressure sensor 2 is corrected for temperature and static pressure, and the output of the static pressure sensor 3 is corrected for temperature, and then the corrected differential pressure signal and static pressure signal are corrected. Then, the output signal of the plant temperature detector 20 and the proportional, integral, and derivative parameter values set in the parameter memory 25 are added to calculate and perform necessary correction to obtain an operation output signal.

The operation signal obtained by the operation is converted to DC 4 to 20 by the D / A converter 26.
It is converted into an analog signal I ₀ of mA.

In this way, the A / D converter 26 can output a differential pressure signal, a static pressure signal, and a temperature signal whose characteristics have been corrected as necessary.

The selection of each output signal is made by the input / output communication device 27.

The production computer 28 writes the map of the temperature correction coefficient and the static pressure correction coefficient into the memory 24, and is used only when manufacturing a transmitter. memory
The map of the temperature correction coefficient and the static pressure correction coefficient written in 24 is specific to each transmitter.

As described above, by using this embodiment, it is not necessary to separately prepare the differential pressure transmitter, the pressure transmitter, and the temperature transmitter, and these three functions can be satisfied by one instrument.

In addition, since both functions of the transmitter and the controller can be obtained, it is possible to use both of them with one device, and the cost and reliability can be greatly improved.

〔The invention's effect〕

ADVANTAGE OF THE INVENTION According to this invention, the conventional various transmitter function can be shared by one unit, Furthermore, the composite transmitter which can also serve also as a controller can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of a process control apparatus according to the present invention, FIG. 2 is a block diagram of a conventional transmitter, and FIG. 3 is a block diagram of a conventional controller. 1 ... combined sensor unit, 2 ... differential pressure sensor, 3 ... static pressure sensor, 4 ... temperature sensor, 5,13,19 ... multiplexer, 7,15,22 ... A / D converter, 8 , 16,23 ... Microprocessor, 20 ... Plant temperature detector, 25 ... Parameter setting memory, 10,18,26 ... D / A converter.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Tomoyuki Tobita 882, Ichimo, Katsuta-shi Naka Works, Hitachi, Ltd. (56) References JP-A-59-114930 (JP, A) JP-A-56-145327 (JP, A) Japanese Utility Model Showa 58-167432 (JP, U)

Claims (2)

(57) [Claims] At least a differential pressure detecting means for detecting a process differential pressure or a pressure difference, a static pressure detecting means for detecting a process static pressure, and the single chip are formed on a single chip. Sensor unit having a temperature detecting means for detecting a temperature inside the housing, storage means for storing each correction coefficient value for correcting each detection signal from the composite sensor unit, and A digital operation means for selectively acquiring a detection signal and correcting each detection signal with each of the acquired detection signals so as to perform a correction operation processing of the detection signal using the correction coefficient value of the storage means; A composite transmitter comprising: an output unit that transmits a calculation result of the calculation unit to the outside; wherein, apart from the temperature detection unit provided in the composite sensor unit, A plant temperature detecting means for directly detecting and outputting a detection signal to the digital calculating means, wherein a differential pressure signal in which static pressure and temperature are corrected, a static pressure signal in which temperature is corrected, and the plant temperature detecting means. A composite transmitter for arbitrarily selecting and outputting each of the obtained temperature signals. 2. A single chip, wherein at least a differential pressure detecting means for detecting a process differential pressure or a pressure difference, a static pressure detecting means for detecting a process static pressure, and the single chip are stored. Sensor unit having a temperature detecting means for detecting a temperature inside the housing, storage means for storing each correction coefficient value for correcting each detection signal from the composite sensor unit, and A digital operation means for selectively acquiring a detection signal and correcting each detection signal with each of the acquired detection signals so as to perform a correction operation processing of the detection signal using the correction coefficient value of the storage means; A composite transmitter comprising: an output unit that transmits a calculation result of the calculation unit to the outside; wherein, apart from the temperature detection unit provided in the composite sensor unit, A plant temperature detecting means for directly detecting and outputting a detection signal to the digital calculating means; storing at least respective parameter setting values of a proportional parameter, a derivative parameter and an integrating parameter, and inputting the parameter setting values to the digital calculating means A differential pressure corrected for the static pressure and the temperature by performing a correction calculation using the respective parameters in addition to the correction calculation processing of each detection signal taken into the digital calculation means. A composite transmitter for arbitrarily selecting and outputting a signal, a static pressure signal whose temperature has been corrected, and a temperature signal obtained by the plant temperature detecting means.