JPH08178787A - Calibrator for pressure transmitter - Google Patents

Abstract

PURPOSE: To shorten calibration working time and to maintain reliability in accuracy checking work by housing a calibration processing apparatus for a pressure transmitter in the same casing body to automatize a series of calibration processing by the control of a controller unit. CONSTITUTION: Units of a calibrator 1 are housed into one box body to make a portable structure. Then, a controller unit 13 selects a pressure transmitter 2 to be calibrated and a pressure value equivalent to 0%, 25%, 50%, 75% and 100% of an output there of is defined as target value. A pressure control unit 11 is commanded to apply a pressure to the transmitter 2 until the target pressure value is reached and an output value of the transmitter 2 is read out by a transmitting communication unit 12 to compute an error based on a difference from the applied pressure value thereby measuring characteristics of the transmitter 2 including non-linearity. When the error is large off a prescribed value in the characteristics of the transmitter 2, the target pressure value is set to a value equivalent to 0% (100%) of the output to perform a processing and when the target pressure value is reached, a command of a zero-point (span point) calibration is provided to the transmitter 2 through the unit 12 to adjust the transmitter 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure transmitter for detecting pressure and transmitting a signal on a two-wire type transmission line, and to a calibration device for measuring characteristics of the pressure transmitter and performing calibration processing such as adjustment thereof. In particular, the present invention relates to a pressure transmitter calibration device that automatically performs a calibration process.

[0002]

2. Description of the Related Art A device called a pressure transmitter is
It incorporates a pressure sensor, detects the physical quantity of the pressure of various plants, converts the value into an electric signal, and transmits it to a higher-level device via a transmission path.

The transmission of the electric signal is standardized when the signal is an analog signal, and an analog current signal of 4 to 20 mA is transmitted between the field device and the host device. .

In general, one-way communication using analog signals has been performed between the field device and the host device.

However, in recent years, field devices with a built-in microprocessor have been developed and put into practical use due to improvements in semiconductor integrated circuit technology. According to this, in addition to unidirectional analog signal communication on the transmission line, bidirectional digital signal communication is performed, and range setting and self-diagnosis of field devices can be remotely commanded. .

In addition, by incorporating a microprocessor and performing various influence value corrections, in terms of performance, ± 0.
It has improved from 2% / FS to ± 0.1% / FS.
When regularly calibrating such a pressure transmitter, various devices such as a pressure generator, a pressure gauge, a pressure reference unit, a DC power supply, a voltmeter (ammeter), and a handheld terminal are connected as shown in FIG. It was necessary to calibrate the pressure transmitter. For this reason, the pressure transmitter has been removed from the plant installation site and calibration work has been carried out in an instrument room or the like, or all of the above-mentioned various devices have been carried to the plant transmitter installation site for calibration work.

Further, calibration work such as pressurization of pressure, measurement of pressure, measurement of output value of the pressure transmitter, calculation of output error of the pressure transmitter, adjustment of the pressure transmitter and the like have been performed manually.

[0008]

However, in the above-mentioned prior art, there is a problem that a large amount of cost and time are required for the calibration work and the reliability of the operation confirmation / accuracy confirmation work is deteriorated due to an error in the work. there were.

In particular, when calibrating a pressure transmitter whose accuracy is improved to ± 0.1% / FS, human intervention is involved, so that the problems of increasing the time for calibration work and maintaining the reliability of accuracy confirmation work are significant. Has become.

According to the present invention, the apparatus for calibrating the pressure transmitter is built in one housing and has a portable structure, so that the pressure transmitter installed in the field is periodically removed, and the instrument room etc. The maintenance work carried out in the field can be carried out while it is installed in the field, and pressure is applied to the pressure transmitter of the calibration device, the applied pressure value is measured, the transmitter output value is read, the error is calculated, and the transmitter is calculated. It is an object of the present invention to solve the above-mentioned problem by automating a series of calibration processes such as adjusting the output of the instrument.

[0011]

In order to achieve the above object, the present invention provides a pressure control unit for measuring the applied pressure value at the same time as applying pressure to the pressure transmitter, and an output signal of the pressure transmitter. It is composed of a transmitter communication unit that communicates with the pressure transmitter at the same time as detecting, and a control device unit that measures the characteristics of the transmitter while controlling the units in synchronization with each other. By automating the calibration process without human intervention, it is possible to eliminate operational errors.

Further, by arranging the respective units in the same housing and having a portable structure, the calibration process of the pressure transmitter can be carried out by only one device,
Further, the apparatus for calibrating the pressure transmitter can be carried out with the maintenance work installed in the field.

[0013]

Therefore, the pressure transmitter calibration device according to the present proposal automatically controls the pressure transmitter to the target pressure value by controlling the pressure control unit and the transmitter communication unit by the control device unit. It is possible to apply the voltage, measure the output value of the pressure transmitter, calculate the error, and output the output error of the pressure transmitter.

For example, by setting the target pressure value to a value corresponding to 0%, 25%, 50%, 75%, 100% of the output of the pressure transmitter, and executing the processing, the output of the pressure transmitter is not changed. Characteristic including linearity can be measured.

When the characteristic of the pressure transmitter deviates from the specified value, the target pressure value is set to 0% of the output of the pressure transmitter.
(100%) is set to a value equivalent to the above processing, and when the target pressure value is reached, a zero point (span point) adjustment command is communicated to the pressure transmitter via the transmitter communication unit. By executing it, the adjustment process of the pressure transmitter can be automatically performed.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 are an internal device configuration diagram and an external view of a pressure transmitter calibrating device using the present invention.

In FIG. 1, a pressure transmitter 2 detects a physical quantity such as a pressure or a differential pressure of a process in various plants and transmits the value to a host device. As the method, there are an analog type in which an output signal is an analog current signal of 4 to 20 mA, or an intelligent type in which a digital signal is placed on the signal and bidirectional communication is performed. . As a method of performing communication of this digital signal, 4 to 20 is used.
There are some which superimpose a digital signal on an analog current signal of mA, or switch between an analog current signal of 4 to 20 mA and a digital signal and output.

Also, this digital signal corresponds to "1" and "0" of the digital signal as in frequency modulation.
In addition to types of frequency signals, those that correspond to "1" and "0" depending on the signal size, such as amplitude modulation, and two types of phases that correspond to "1" and "0", such as phase modulation Things are used.

The pressure transmitter 2 is normally wired to a host device using a pair of signal lines, and transmits a signal such as the analog current signal of 4 to 20 mA and supplies operating power to the pressure transmitter. Are performed through the pair of signal lines. When calibrating the pressure transmitter 2, the pair of signal lines are removed and connected to one of the plurality of transmitter communication units 12 built in the calibration device 1.

The piping is also separated from the plant piping and connected to the secondary side connection port in the calibration device 1.

The calibration device 1 reads data such as set values of the pressure transmitter to be calibrated from the external computer 3 and outputs the calibration data of the pressure transmitter implemented by the calibration device 1 to the external computer 3. An interface for exchanging information with the computer 3 is built in the control unit 13. As an interface for exchanging this information, there are serial communication such as RS-232-C or a driver of a storage medium such as a floppy diskette.

Further, the controller unit 13 of the calibration apparatus 1
A memory for storing information of a plurality of pressure transmitters (for example, set values of the pressure transmitters for the number of units to be calibrated in one day and calibration data thereof) is built therein.
Therefore, it is not necessary to carry the external computer together with the calibration device 1 to the place of the plant where the pressure transmitter 2 is installed, and the timing for exchanging the information is the calibration before and after the maintenance and inspection of the pressure transmitter. This can be done while the device 1 is in the instrument room.

Next, the internal operation of the calibration device 1 will be described.

The pressure cylinder 4 is connected to the connection port on the primary side of the calibration device 1 and supplies a pressure larger than the maximum pressure value applied to the pressure transmitter 2 to be calibrated to the calibration device 1. The pressure control unit 11 controls a built-in control valve to control the pressure applied to the pressure transmitter via the connection port on the secondary side, and at the same time, measures the applied pressure value with a built-in sensor. A plurality of these sensors are built in, and the sensor to be used is determined according to the pressure range.

The transmitter communication unit 12 includes the pressure transmitter 2
To supply the operating power of the pressure transmitter 2 and detect the current output signal of the pressure transmitter 2. When the pressure transmitter 2 is an intelligent type capable of digital signal communication, the transmitter communication unit 12 not only detects the current output signal of the pressure transmitter 2 but also measures the pressure transmitter 2 by digital signal communication. It is possible to read out set values such as the pressure range and damping time, and to issue an adjustment command to the pressure transmitter 2.

Further, the transmitter communication unit 12 can incorporate a plurality of units corresponding to the communication protocol of digital signals.

The power supply unit 15 is arranged so that the calibration work can be performed at the place of the plant where the pressure transmitter 2 is installed.
A battery having a capacity capable of performing the calibration work for the number of units to be carried out in one day is built in, and power is supplied to each unit in the calibration apparatus 1 via the DC power supply.

Further, the battery can be charged from an external AC power source through a built-in charging circuit.

In response to a command from the control unit 13, the operation display unit 14 reads data from the external computer 3 and stores in the internal memory the data such as set values of the pressure transmitter to be calibrated and the calibration processing. A sequence can be displayed and selection can be made by interactive key input using the keyboard.

The control device unit 13 controls the operation of the entire calibration device 1 including the pressure control unit 11, the transmitter communication unit 12, the operation display unit 14, and the interface with the external computer 3.

Each of the above-mentioned units is built in one housing to have a portable structure as shown in FIG.

An operation example when the calibration device 1 carries out the calibration operation will be described below.

The controller unit 13 includes, for example, TAG data indicating the installation location of the pressure transmitters in the plant among the data such as the set values of the plurality of pressure transmitters to be calibrated stored in the built-in memory. Representative data of a plurality of such units are displayed on the display unit of the operation display unit 14, and the pressure transmitter 2 to be calibrated is selected using the keyboard.

Next, the control unit 13 applies a pressure value corresponding to 0% of the output of the pressure transmitter 2 to the pressure transmitter 2 in order to measure the characteristic of the output of the pressure transmitter 2. The pressure control unit 11 is instructed, and at the same time, the applied pressure detected by the pressure control unit 11 is read out.
When it is detected that the applied pressure has reached a pressure value equivalent to 0%, the control device unit 13 issues a pressure application stop command to the pressure control unit 11, and the pressure transmission read out via the transmitter communication unit 12. After confirming that the output value of the pressure transmitter 2 is stable, the output value of the pressure transmitter 2 is read.

The controller unit 13 outputs this output value and 0.
Due to the difference with the output value equivalent to%, the output of the pressure transmitter 2 becomes 0
The error in% is calculated and the value is displayed on the operation display unit 1
No. 4 is displayed.

The above-described operation is executed, for example, for output values of the pressure transmitter 2 corresponding to values of 25%, 50%, 75% and 100%, and the characteristics of the pressure transmitter 2 including non-linearity. To measure.

When the characteristic of the pressure transmitter deviates from the specified value and the error is large, the control unit 13 sets the target pressure value to a value corresponding to 0% (100%) of the output of the pressure transmitter, and When the target pressure value is reached, a zero point (span point) adjustment command is communicated to the pressure transmitter 2 via the transmitter communication unit 12, and the adjustment process is executed for the pressure transmitter 2. To do.

After performing the adjustment process, the process of measuring the characteristic of the pressure transmitter 2 is performed again, and the control unit 1
3 stores the characteristic values before and after the adjustment as data in the built-in memory.

With the above operation, according to the present invention, there is an effect that characteristic measurement and adjustment processing of the pressure transmitter can be automatically performed.

Further, by connecting the external computer 3 and reading the characteristic values before and after the adjustment stored in the built-in memory, the pressure transmitter 1 in the external computer 3 is read.
There is also an effect that it is possible to manage maintenance data such as the characteristic change value of, the presence or absence of adjustment, and the like.

[0042]

As is clear from the above description, a series of calibration processes can be carried out without human intervention by carrying out the calibration work using the pressure transmitter calibration apparatus according to the present invention. The advantages are that the time for calibration work can be shortened and the reliability of accuracy confirmation work can be maintained.

Further, since the apparatus for performing the calibration process is built into one housing and has a portable structure, the calibration work can be easily performed without removing the pressure transmitter installed in the field. The effect is that you can do it.

[Brief description of drawings]

FIG. 1 is an internal configuration diagram showing an embodiment of a calibration device according to the present invention.

FIG. 2 is an external view showing an embodiment of a calibration device according to the present invention.

FIG. 3 is a diagram showing an example of an apparatus configuration for performing a conventional calibration process.

[Explanation of symbols]

1 ... Calibration device, 2 ... Pressure transmitter, 3 ... External computer, 4 ... Pressure cylinder, 11 ... Pressure control unit, 12 ...
Transmitter communication unit, 13 ... Control device unit, 14 ...
Operation display unit, 15 ... Power supply unit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (71) Applicant 000003078 Toshiba Corporation, 72 Horikawa-cho, Sachi-ku, Kawasaki-shi, Kanagawa Prefecture (71) Applicant 000230032 Nippon Beret Co., Ltd. 511 Haraki, Nirayama-cho, Tagata-gun, Shizuoka Prefecture (72) Inventor Makoto Kogure 882 Ichige, Ichima, Hitachinaka City, Ibaraki Prefecture Hitachi Ltd. Measuring Instruments Division (72) Inventor Masahiro Kaneko 9-2-1 Kurihama, Yokosuka City, Kanagawa Prefecture (72) Inventor, Yokosuka Thermal Power Plant Toshiro Kurihara 2-9-32 Nakamachi, Musashino-shi, Tokyo Within Yokogawa Electric Co., Ltd. (72) Inventor Hiroshi Watanabe 4-1-1 Omagari, Samukawa-cho, Takaza-gun, Kanagawa Prefecture Yamatake Honeywell Co., Ltd. (72) Invention Hirai Renzo 1st Toshiba-cho, Fuchu-shi, Tokyo Inside the Fuchu factory, Toshiba Corporation (72) Inventor Tetsuya Ishizuka Prefecture Tagata District Nirayama timber 511 Japan Beare over within Co., Ltd.

Claims (6)

[Claims] 1. A measuring device comprising means for controlling the pressure applied to the pressure transmitter, means for measuring the pressure applied to the pressure transmitter, and means for measuring an electric output signal of the pressure transmitter. In the device that measures the error of the pressure transmitter from the applied pressure value to the pressure transmitter and the measured output value of the transmitter and performs the calibration process when the error is large, the pressure applied to the pressure transmitter. A pressure control unit for controlling and measuring
At least one transmitter communication unit that detects the output signal of the pressure transmitter, and controls the pressure control unit and the transmitter communication unit to instruct the transmitter communication unit and the pressure control unit to perform the calibration process. It is composed of a controller unit for automating the calibration process, and each unit is built in a single housing to have a portable structure, and the calibration operation is automatically performed by moving to the installation location of the pressure transmitter. A pressure transmitter calibration device characterized in that it is possible. 2. The pressure transmitter calibration device according to claim 1, wherein the operating power of the pressure transmitter is supplied from an oscillator communication unit, and the operating power of the pressure transmitter is supplied and an output signal is detected. A calibration device for a pressure transmitter, characterized in that the configuration is performed from the same transmitter communication unit. 3. The pressure transmitter calibration device according to claim 1, wherein the calibration device has a built-in interface circuit for communicating with an external computer, and the set value of the pressure transmitter to be calibrated from the external computer. And a function for outputting the calibration data of the pressure transmitter to the external computer. 4. The pressure transmitter calibration device according to claim 1, further comprising a storage medium for exchanging information with an external computer, and an interface circuit for connecting the storage medium and the calibration device. A calibration device is built-in, and has a function of reading out and setting a set value of a pressure transmitter to be calibrated from the storage medium, and a function of writing calibration data of the pressure transmitter to the storage medium. A calibration device for a pressure transmitter, comprising means for removing a medium from the calibration device. 5. The calibration device for a pressure transmitter according to claim 1, 2, 3, or 4, wherein a set value such as an output range value set inside the pressure transmitter is passed through the transmitter communication unit. Of the pressure value output from the pressure control unit to the output range value of the read out transmitter, the pressure value and the output range value of the pressure transmitter When an error exceeds an error of a constant value, a function of communicating with the pressure transmitter via the transmitter communication unit and issuing a calibration command,
A pressure transmitter calibration device, characterized by performing a calibration process of a pressure transmitter. 6. The pressure transmitter calibration device according to claim 1, 2, 3, 4, or 5, wherein the transmitter communication is compatible with a communication protocol used between the pressure transmitter communication unit and the transmitter. A pressure transmitter characterized in that a unit is provided for each communication protocol, at least one transmitter communication unit is built in the calibration device, and the transmitter communication unit can be attached to and detached from the calibration device. Calibration equipment.