JPH04111699U - intelligent field instrument - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an intelligent field instrument in which, when parameters of the field instrument are changed using a communication device, the parameters and device information are not changed even if a communication cable is connected incorrectly. [Structure] In an intelligent field instrument, a switch is provided in the field instrument, the state of this switch is imported into a microcomputer, and when the switch is on, for example, the parameters of the field instrument are changed and adjusted by communicating with a communication device. I tried not to.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention is a differential pressure/pressure transmitter, an electromagnetic flow meter, which is a field instrument for industrial measurement, etc. , temperature transmitters, etc., especially intelligent devices equipped with microcomputers. Concerning field instruments.

0002

[Conventional technology]

Traditionally, a microcomputer has been installed to perform sensor linearity correction calculations and measurements. Intelligent field instruments that calculate output values corresponding to ranges are well known. ing. This intelligent field instrument is supplemented by a microcomputer. In addition to being more accurate, it also superimposes a digital signal on a 4-20mA analog signal. By doing so, communication is possible with the communication device connected to the signal line, and the measurement range is ・Remotely change settings of parameters such as operating time constants and device information such as tag No. It has features such as being able to read out. The communication device is attached to the communication device. Communication can be started by simply connecting the installed communication cable to the signal line of the field instrument. can. Therefore, remote settings, changes, and reading using communication devices are easy and convenient. However, on the other hand, since anyone can easily change the above parameters and device information, For example, an outsider may accidentally operate a communication device and disrupt plant operation. Conceivable. For such cases, attach a key to the communication device or remove the memory. By installing a card and allowing the registration of a PIN number, the number of users of the communication device is limited. Ta.

0003

[Problem that the idea aims to solve]

Intelligent field instruments communicate the above parameters using the communication device as described above. Data and device information can be changed and read remotely, eliminating the need for people to be in the central control room. Communication is often carried out using The central control room receives signals from many field instruments. The signal lines of the desired field instrument are selected from among these many signal lines. You will need to find it without making a mistake and connect the communication cable. The above conventional communication equipment You can attach a key or use a memory card to register your PIN number, as in the case of Even if you limit the number of people handling communication equipment by making sure that the communication cables are connected to the wrong signal line, If you connect it and do not notice it, the parameters of the field instrument may be incorrectly Settings were sometimes changed. In particular, important rules such as boiler fuel control Intelligent field instruments used in If a setting change occurs, it could lead to a major accident that could result in a plant explosion or other life-threatening accidents. There was a possibility.

0004 The purpose of the present invention is to Even if the communication cable is connected incorrectly, the above parameters and device information will not change. Our goal is to provide intelligent field instruments that are not only available.

[0005]

[Means to solve the problem]

To achieve the above purpose, switches are designed into intelligent field instruments. The state of this switch was then imported into the microcomputer.

[0006]

[Effect]

When users use important field instruments, parameter settings may be changed. If you think that doing so would be bad, turn on the above switch. microcomputer When this switch is on, the parameter settings can be changed by communication using the communication device. Avoid making any changes.

[0007]

【Example】

An embodiment of the present invention will be described below with reference to the drawings. Figure 1 shows field instruments. A block diagram of the present invention implemented in an intelligent differential pressure/pressure transmitter is shown. . In the figure, a composite sensor 101 provided in a transmitter main body 100 mainly A differential pressure measurement sensor 101A that is sensitive to pressure, a static pressure measurement sensor that is mainly sensitive to static pressure. There are three types of sensors: a sensor 101B, and a temperature measurement sensor 101C that is mainly sensitive to temperature. The two resistors are placed on the same chip. Multiplexer these sensors and converted to digital by an A/D converter. These three types The digital value of the sensor is

[0008]

[Math 1] Dp=f(P,S,T)

[0009]

[Math 2] Ds=g(P,S,T)

0010

[Math 3] Dt=h(P,S,T) (Here, Dp, Ds, and Dt are differential pressure, static pressure, and temperature sensors 101A and 101B, respectively. , 101C output, P, S, T are differential pressure, static pressure, and temperature inputs) It is expressed as Each input value is found by solving the simultaneous equations of Equations 1 to 3.

[0011]

[Math 4] P=F(Dp, Ds, Dt)

0012

[Math 5] S=G(Dp, Ds, Dt)

[0013]

[Math 6] T=H(Dp, Ds, Dt) The work of identifying the functions of f, g, and h and solving the simultaneous equations is done in advance during the production process. Each sensor is processed by a large-scale production computer. will be held. The coefficients of Equations 4 to 6 or the calculated values of Equations 4 to 6 are used as node data. It is stored in the EPROM 107 as a data. The microcomputer 104 Input value based on the information stored in EEPROM107 from the digital value of the sensor Calculate. Furthermore, the microcomputer 104 controls the set measurement range. Based on the information, calculate the value to be output from the calculated input value. Due to the above The calculated output value is converted into an analog signal by the D/A converter 105, and Obtain an output signal of mA. Parameters such as the above range information are passed through the signal line 201. The digital I/O 109 is transmitted by the communication device 300 connected to the communication cable 301. The data is set by communicating through the non-volatile memory Stored in EEPROM108. In addition, 202 is a power supply, and 203 is a central power supply in a remote location. This is a receiving device in the instrumentation room, and the above 4-20mA analog signal is sent to the receiving resistor 203A. is converted into a voltage signal. The switch 110 provided in the field instrument is , the state is imported into the microcomputer, and the switch When is on, settings cannot be changed via communication.

[0014] A field instrument user first installs the field instrument in the plant and takes measurements. Perform range settings, damping settings, etc. to eliminate the effects of installation orientation. After making the first zero adjustment, if the field instrument is important, set the parameters. If you do not want to change it, turn on the above switch. For field instruments, this A microcomputer monitors the status of the switch, and when the switch is on, When doing so, be careful not to perform operations that may cause sudden changes in the output, such as changing parameters or adjusting the zero point. As a result, plant operations are not disrupted. This switch is shown in Figure 3. As you can see, it is a hard switch that can be seen by removing the cover of the field instrument.

[0015] FIG. 4 is a diagram showing another embodiment of the present invention, which differs from FIG. 1 in the hardware switch. Instead of a switch, a soft memory switch was installed in the nonvolatile memory. to this There is no need to go to the field instrument to change switches. The switch can be changed by communicating with the communication device 300. Wear.

[0016]

[Effect of the idea]

According to the present invention, when changing the settings of the above parameters and device information, it is possible to Even if the communication cable is connected incorrectly, the above parameters and device information will not be changed. For example, if the output of a field instrument suddenly changes in an important loop, it can cause a major accident. A field instrument that can prevent this is obtained. Therefore, the effect of the present invention is significant.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a diagram illustrating a typical use of a field instrument.

FIG. 3 is an external view of an embodiment of the present invention.

FIG. 4 is a block diagram of another embodiment of the present invention.

[Explanation of symbols]

100...Field instrument, 101...Composite sensor, 102
...Multiplexer, 103...AD converter, 104...Microcomputer, 105...DA converter, 106...RA
M, 107...EEPROM, 108...EPROM, 10
9...Digital I/O, 110...Switch, 300...Communication device, 301...Communication cable.

Claims (2)

[Scope of utility model registration request] Claim 1: A field instrument such as a pressure/differential pressure transmitter or an electromagnetic flowmeter is equipped with a non-volatile memory for storing data such as operating conditions and tag numbers, a microcomputer for performing correction calculations, etc. In an intelligent field instrument that can communicate with a communication device to change the settings of the data, the field instrument is provided with a switch, the state of this switch is imported into the microcomputer, and when the switch is on, the communication device An intelligent field instrument characterized in that parameters of the field instrument are not changed or adjusted through communication with the field instrument. 2. An intelligent field instrument according to claim 1, wherein said switch is a nonvolatile memory, and said communication device switches said memory switch of said nonvolatile memory.