JP2004085288A - Multivariable transmitter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multivariable transmitter capable of facilitating a complicated simulation by utilizing a memory storage pseudo variable by a communication command from a support tool. <P>SOLUTION: This multivariable transmitter is equipped with an arithmetic processing means for inputting variables related to a plurality of physical quantities of a process and measuring the physical quantities determined by operation of the variables, and an output means for transmitting the output of the arithmetic processing means to the outside as a transmission signal. The transmitter can communicate with an external support tool by a communication signal superimposed on the transmission signal. The transmitter is also equipped with a means for setting pseudo variables related to the plurality of physical quantities, and a switching means for supplying the pseudo variables to the arithmetic processing means by a command from the support tool. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a simulation function of a multivariable transmitter for inputting variables related to a plurality of physical quantities of a process and measuring physical quantities obtained by calculating these variables.
[0002]
[Prior art]
In a mass flow meter using a general-purpose differential pressure transmitter used as a field device for process control, the differential pressure, which is a physical quantity to be measured directly, is measured with a differential pressure sensor, and the physical quantity for calculating the mass flow rate is measured. Are measured by the pressure sensor and the temperature sensor, and the mass flow rate, which is the target physical quantity, is indirectly measured by arithmetic processing using three variables.
[0003]
FIG. 6 is a functional block diagram showing a conventional configuration of such a multivariable transmitter. 1 is a differential pressure sensor, 2 is a pressure sensor, 3 is a temperature sensor. Reference numeral 4 denotes an A / D converter for converting a measurement signal of the differential pressure sensor 1 into a digital value ed, reference numeral 2 denotes an A / D converter for converting a measurement signal of the pressure sensor 2 into a digital value ep, and reference numeral 3 denotes a measurement signal of the temperature sensor 3. This is an A / D converter for converting into a digital value et.
[0004]
The digital values ed, ep, et, which are three variables, are input to the arithmetic processing means 7 constituted by a microprocessor (MPU), where the mass flow rate is calculated, and the digital flow rate signal eq is output. 8 is a memory.
[0005]
Reference numeral 9 denotes a D / A converter for converting the mass flow rate signal eq into an analog voltage value, and reference numeral 10 denotes output means, which converts the voltage value of the D / A converter 9 into a current transmission signal I such as 4 to 20 mA, and outputs an external load. 11 and a DC power supply 12 are supplied to a series circuit.
[0006]
Reference numeral 13 denotes a support tool connected in parallel to the output means 10, which communicates with the arithmetic processing means 7 via the communication interface 14 by a digital communication signal superimposed on the transmission signal to check whether the input / output characteristics are as designed. Confirm the configuration such as range setting.
[0007]
[Problems to be solved by the invention]
In order to check whether the input / output characteristics are as designed, it is necessary to perform a simulation in which an input variable is input as a plurality of sensor signals within the range or over the range, and the output is checked. However, when there are a plurality of variables to be calculated, the configuration on the sensor side for the simulation becomes large and the number of combinations of variables becomes enormous, so that the cost for the simulation increases.
[0008]
An object of the present invention is to realize a multivariable transmitter which facilitates complicated simulations by utilizing memory storage pseudo variables according to a communication command from a support tool.
[0009]
[Means for Solving the Problems]
The configuration of the present invention for achieving such an object is as follows.
(1) Arithmetic processing means for inputting variables relating to a plurality of physical quantities of a process and measuring physical quantities determined by arithmetic operations of these variables, and output means for transmitting an output of the arithmetic processing means to the outside as a transmission signal In a multivariable transmitter that can communicate with external support tools by communication signals,
A multivariable transmitter, comprising: means for setting a pseudo variable relating to the plurality of physical quantities; and switching means for supplying the pseudo variable to the arithmetic processing means in accordance with a command from the support tool.
[0010]
(2) The multivariable according to claim 1, wherein the pseudo variable is stored in a memory included in the arithmetic processing unit, and is read out from the memory and set according to a command from the support tool. Transmitter.
[0011]
(3) A plurality of the pseudo variables are stored in the memory for each variable, sequentially read and supplied to the arithmetic processing means, and a plurality of simulation arithmetic processes are executed. The multivariable transmitter according to claim 1.
[0012]
(4) The multivariable transmitter according to any one of claims 1 to 3, wherein the pseudo variable is automatically generated based on a setting condition of the simulation operation processing.
[0013]
(5) The multivariable transmitter according to any one of claims 1 to 4, wherein the simulation calculation processing result is recorded in the memory, transmitted to the support tool by communication, and displayed / recorded. .
[0014]
(6) The multivariable transmitter according to any one of claims 1 to 4, wherein the simulation calculation processing result is directly transmitted to the support tool by communication, and is displayed and recorded.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a functional block diagram showing an example of a multivariable transmitter to which the present invention is applied. The same elements as those described in the conventional transmitter of FIG.
[0016]
Hereinafter, the configuration of the characteristic portion of the present invention will be described. Reference numeral 15 denotes a pseudo differential pressure setting unit that outputs a pseudo differential pressure signal md of a digital value. Reference numeral 16 denotes a pseudo pressure setting unit that outputs a pseudo pressure signal mp of a digital value. 17, pseudo temperature setting means for outputting a pseudo temperature signal mt of a digital value.
[0017]
Reference numeral 18 denotes first switching means for switching between the digital value ed from the A / D converter 4 and the digital value md of the pseudo differential pressure setting means 15 and supplying the digital value md to the arithmetic means 7. Reference numeral 19 denotes second switching means for switching between the digital value ep from the A / D converter 5 and the digital value md of the pseudo differential pressure setting means 16 and supplying the digital value md to the arithmetic means 7. Reference numeral 20 denotes a third switching unit that switches the digital value et from the A / D converter 6 and the digital value mt of the pseudo differential pressure setting unit 17 and supplies the digital value mt to the arithmetic unit 7.
[0018]
The first, second, and third switching units 15, 16, and 17 operate in conjunction with each other in response to an operation signal from the arithmetic processing unit. The setting of the pseudo signal to the pseudo differential pressure setting means 15, the pseudo pressure setting means 16, and the pseudo temperature setting means is executed by loading the pseudo signal stored in the memory 8.
[0019]
The pseudo signal can be created by manually inputting in advance, or by automatically generating a pseudo variable based on the setting conditions (span and number of simulations) of the simulation calculation process.
[0020]
The operation of the first to third switching means 15, 16, 17 and the loading of the pseudo signals md, mp, mt from the memory 8 to the pseudo differential pressure setting means 15, pseudo pressure setting means 16, pseudo temperature setting means are supported. It is instructed by communication from the tool 13.
[0021]
FIG. 2 is a functional block diagram in which pseudo signals md, mp, and mt are supplied to the arithmetic processing device 7 as inputs and a pseudo mass flow rate Qm calculated as an output is obtained.
[0022]
FIG. 3 shows the contents of the memory 8 in the case of executing a simulation in which a plurality of pseudo signals are switched and supplied to a specific variable by a command from the support tool 13 and a pseudo mass flow rate Qm is calculated and output each time. FIG.
[0023]
In this example, the differential pressure, pressure, and temperature variables are x, y, z, y and z are fixed pseudo values y, z, and the variable x relating to the differential pressure is n pseudo values x1, x2, x3. ... Switch to xn and change. The pseudo mass flow rates Qm1, Qm2, Qm3,... Qmn obtained by the arithmetic processing are stored in tables corresponding to x1, x2, x3,.
[0024]
The pseudo mass flow rates Qm1, Qm2, Qm3,... Qmn stored in the memory 8 are read into the support tool 13 by communication, and a graph as shown in FIG. 4 can be displayed / recorded.
[0025]
By comparing the graph of the simulation calculation result by such a pseudo input with the normal graph, it is possible to easily confirm whether or not the calculation processing of a plurality of variables is normally executed.
[0026]
For the variables y and z, a plurality of pseudo data are prepared, a simulation similar to that for the variable x is performed, and it can be easily confirmed from the support tool whether or not the correction operation is normally executed. . Furthermore, it is also possible to perform a composite simulation in which y and z are changed together with the variable x.
[0027]
FIG. 5 is a functional block diagram of a multivariable transmitter showing another embodiment of the present invention. The difference from FIG. 1 is that the output of the arithmetic processing means 7 is not converted to an analog signal, but is transmitted via a communication interface. Connected to a digital bus.
[0028]
21 is a digital bus, and 22 and 23 are terminators connected to both ends of the bus. Reference numeral 24 denotes a communication interface for connecting the arithmetic processing means 7 and the digital bus 21, and forms an output means of the transmitter.
[0029]
The support tool 13 is connected to the digital bus 21 and communicates with the arithmetic processing unit 7 via the communication interface 24. The simulation function according to the command of the support tool 13 is exactly the same as that of FIG.
[0030]
FIG. 3 shows an embodiment in which the result of the simulation by the pseudo input is recorded in the memory. However, it is also possible to transmit the data by communication at any time without storing the result in the memory and record the data by a support tool or the like. In this case, there is an advantage that a large memory size is not required and the number of pseudo data is theoretically increased to infinity, but there is also a disadvantage that communication is required every time and processing takes time.
[0031]
【The invention's effect】
As apparent from the above description, according to the present invention, in a multivariable transmitter for inputting variables related to a plurality of physical quantities of a process, a simulation is performed by using a memory storage pseudo-variable by a communication command from a support tool. It can be very easy.
[0032]
Further, the behavior in the case of an abnormal input can be confirmed by setting the over-range pseudo input signal, and appropriate alarm setting can be performed.
[Brief description of the drawings]
FIG. 1 is a functional block diagram illustrating an example of a multivariable transmitter to which the present invention is applied.
FIG. 2 is a functional block diagram in which a pseudo signal is supplied to an arithmetic processing unit to obtain a calculated pseudo mass flow rate.
FIG. 3 is a table showing contents of a memory when a simulation for calculating and outputting a pseudo mass flow rate is executed.
FIG. 4 is a graph in which a pseudo mass flow rate stored in a memory is read and displayed / recorded on a support tool through communication.
FIG. 5 is a functional block diagram showing another embodiment of the multivariable transmitter to which the present invention is applied.
FIG. 6 is a functional block diagram showing a conventional configuration of a multivariable transmitter.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Differential pressure sensor 2 Pressure sensor 3 Temperature sensor 4, 5, 6 A / D converter 7 Operation processing means 8 Memory 9 D / A converter 10 Output means 11 External load 12 DC power supply 13 Support tool 14 Communication interface 15 Pseudo differential pressure setting Means 16 pseudo pressure setting means 17 pseudo temperature setting means 18, 19, 20 First, second, third switching means

Claims (6)

A plurality of variables related to the physical quantity of the process are input, and an arithmetic processing means for measuring a physical quantity obtained by calculating these variables; and an output means for transmitting an output of the arithmetic processing means to the outside as a transmission signal. In a multivariable transmitter that can communicate with external support tools by signals,
A multivariable transmitter, comprising: means for setting a pseudo variable relating to the plurality of physical quantities; and switching means for supplying the pseudo variable to the arithmetic processing means in accordance with a command from the support tool. 2. The multivariable transmitter according to claim 1, wherein the pseudo variable is stored in a memory included in the arithmetic processing unit, and is read out from the memory and set according to a command from the support tool. A plurality of the pseudo variables are stored in the memory for each variable, sequentially read and supplied to the arithmetic processing means, and a plurality of simulation arithmetic processes are executed. Or the multivariable transmitter according to 2. The multivariable transmitter according to any one of claims 1 to 3, wherein the pseudo variable is automatically generated based on a setting condition of the simulation operation process. The multivariable transmitter according to any one of claims 1 to 4, wherein the simulation calculation processing result is recorded in the memory, transmitted to the support tool by communication, and displayed / recorded. The multivariable transmitter according to any one of claims 1 to 4, wherein the simulation calculation processing result is directly transmitted to the support tool by communication, and is displayed and recorded.

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