JP3143023B2 - Flow calculator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow rate calculator, and more particularly, to a flow rate signal of a gas or a liquid, which is subjected to a temperature / pressure correction calculation, and a flow rate signal, a density and a mass of a reference state at a predetermined level. The present invention relates to a flow rate calculator that outputs electric signals.

[0002]

2. Description of the Related Art In a flow rate measurement of a gas, a liquid, or the like, a flow meter to be applied is selected according to the temperature, pressure, flow velocity, and required accuracy of a fluid to be measured. As the flow meter, for example, a positive displacement flow meter, a vortex flow meter, a turbine flow meter, or the like is used, and the flow signal is mainly output as a flow pulse.
The pulse constant of the flow pulse, that is, the fluid volume per pulse, differs depending on the type and size of the flow meter, and changes depending on the temperature and pressure of the fluid.

[0003] The flow rate converter can be connected to any of the transmitters of the various types of flow meters described above. For the uncorrected flow signal output from the meter,
Reference condition, for example, reference temperature 15 ° C, reference pressure 0.1M
This is a converter for converting into a flow signal in Pa (megapascal) and outputting a corrected flow signal and a flow pulse of a predetermined level, for example, 1 to 5 V, 4 to 20 mA.

FIG. 3 is a block diagram for explaining the configuration of a conventional flow rate calculator. In the figure, first, a flow rate pulse is input to an input terminal 21, a state quantity signal such as temperature and pressure is input to an input terminal 22, and an analog signal such as a state quantity signal is input to an A / D (analog / digital) conversion circuit 23. The digital conversion is performed. Although the number of input terminals 22 is the same as the number of state quantity signals, only one input terminal is shown in FIG. 3 for the sake of simplicity.

The A / D conversion circuit 23 is provided with, for example, a trim (variable resistor) 23a for performing zero adjustment and a trim 23b for performing span adjustment. These trims 23a and 23b are adjusted. Thus, when an analog input signal within a predetermined level range is applied, the converted digital value becomes a theoretical value.

For example, when converting an analog input signal of 1 to 5 V into digital data of 500 to 2500 counts, the zero adjustment trim 23 a is adjusted so that when 1 V is applied to the input terminal 22, the digital data becomes 500 counts. The span adjustment trim 23b is adjusted so that 2500 counts are obtained when is added. in this way,
Repeat the adjustment until the input signal 1-5V is 500-
The digital data is 2500 counts. Moreover, this adjustment work is performed in accordance with the specifications each time the specifications of the flow rate converter are determined.

[0007] A ROM (Read Only Memory) 27 incorporates a program of a correction operation formula for performing temperature and pressure correction on the input flow rate pulse. An electrically rewritable PROM as the ROM 27
(Programable ROM) is often used. ROM2
7, a program corresponding to the correction operation formula applied to the flow rate calculator is incorporated, and the ROM 27 selected according to the user's specification is replaced with the flow rate calculator.

[0008] RAM (Ramdom Access Memory) 28
Stores an input signal accessed via the (I / O) 24, and the CPU 26 stores the ROM 27, the RAM 2
8 and performs a correction operation in accordance with the stored information of FIG.
O) D / A converter 29 which is hardware via 24
Is converted into a flow signal of a predetermined level and output from the outlet terminal 31. The flow pulse is also corrected to the flow pulse in the reference state and output from the output terminal 30.

[0009]

In the conventional flow rate calculator shown in FIG. 3, a correction calculation formula calculated by the flow rate calculator is as follows.
The conditions for the calculation of the correction formula or the conditions for deriving the calculation formula are stored in a ROM 27 such as a PROM. There was an inconvenience of being replaced every time the specification was changed.

A calibration operation for adjusting the output flow rate signal specified in the specification to a predetermined level is also performed every time the ROM 27 is replaced in correspondence with the ROM 27. It required precision standards and skilled workers. For this reason, in the case of a specification change requiring adjustment of the hardware to some extent, there is an inconvenience that the flow converter must be sent back to the manufacturing factory where the conditions for the above adjustment can be satisfied and readjusted. Not only did it require a lot of man-hours, but became expensive.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and is intended to prevent the modification of the ROM 27 from giving priority to the hardware calibration. The calibration operation is performed independently of the contents, and is also performed independently in the application and parameter setting, so that the calibration operation is separated and the calibration operation is simplified without being attached to the arithmetic expression. Provide a flow rate calculator that enables anyone to carry out calibration, anywhere, and that can quickly respond to changes in specifications and expand the range of application The purpose is to do so.

[0012]

According to the present invention, in order to solve the above-mentioned problems, (1) a target correction operation expression is selected from a large number of stored correction operation expressions, and the selected correction operation expression is selected. An application setting function for inputting a state quantity signal such as a flow pulse of a gas or a liquid and a temperature / pressure, and calculating and outputting a flow signal of a predetermined level in a reference state, an application setting function for selecting the target correction operation formula. The parameter setting function for setting the parameters of the selected correction arithmetic expression and the calibration setting function for converting the target flow signal into a flow signal of a predetermined level are non-interfering with each other. Independently configured as
That each of the setting functions is provided to an IC card,
(2) In the above (1), the calibration setting may be performed by converting the calibration setting between an internal reference power supply built in the flow calculator or an external reference power supply installed outside the flow calculator. And a value of a ratio between the output of the converter when the signal is input to the reference power supply and the reference power supply, and a correction operation is performed based on the stored value of the ratio.

[0013]

The correction arithmetic expression specified in the application IC card is selected from among a large number of correction arithmetic expressions stored in the flow rate calculator or an arithmetic expression derived from the outside, and the parameters stored in the parameter IC card are changed. Access the selected correction equation. Also, if the input / output signal is I / O
The converter input and output through the I
The adjustment is performed according to the C card, and the software function and the hardware function (in this example, the converter) of the flow rate calculator are made independent from each other so as to output the flow rate signal of the target level. That is, the functions that are dependent on each other are configured as independent functions by introducing an IC card, so that various functions can be handled.

[0014]

【Example】

Embodiment 1 (corresponding to claim 1) FIG. 1 is a block diagram for explaining an embodiment of a flow rate calculator according to the present invention, in which 1 is an input terminal of a flow rate pulse, and 2 is a state quantity signal. , Input terminal 3, A / D converter,
4 is an I / O, 5 is a bus, 6 is a CPU, 7 is a ROM, 8 is a RAM, 9 is a D / A converter, 10 is an output terminal of a corrected flow pulse, and 11 is an output of a corrected flow signal. Terminal,
12 is an IC card, 13 is an IC controller, 14, 1
5 is an internal reference power supply, and 16 is a flow rate calculation unit.

In FIG. 1, a flow rate transmitter (not shown) of a flow meter selected according to the purpose is connected to an input terminal 1 for a flow pulse, and an input terminal 2 for a state quantity signal is connected to an input terminal 2 for a state quantity signal. For example, a temperature signal of the fluid is input. Input terminals for pressure signals etc. are also provided as other state quantities,
In the figure, it is omitted to avoid complication.

The flow rate calculator according to the present invention shown in FIG.
A flow rate calculation unit 16, a CPU 6, a ROM,
And an IC card 12 for accessing the RAM 8. The IC card 12 is composed of IC cards 12a, 12b... 12n each having an independent function.

The flow rate calculating section 16 converts the flow rate pulse input from the input terminal 1 and an analog signal such as temperature and pressure input from the input terminal 2 through an A / D through an amplifier (not shown).
The signal is converted into a digital signal by the converter 3, and (I / O) 4
And CPU 6, RAM 7 and RAM via bus 5
Access 8 Furthermore, the flow pulse corrected and calculated via (I / O) 4 is connected to the output terminal 10, and
A D / A converter 9 for outputting an analog-converted flow signal of a predetermined level is connected to an output terminal 11.

On the other hand, as is well known, the IC card 12
A CPU (not shown) which operates based on an external signal, a ROM (not shown) storing a control program, and a RAM (not shown) which is a register are connected to other circuits via a data bus for control. The one-chip microcomputer is controlled by this microcomputer,
It has an EEPROM (electrically rewritable semiconductor memory circuit) and a control circuit for writing and reading data input from an I / O terminal, and is connected to the CPU 6 via an IC controller 13. I have.

In the flow rate calculator configured as described above, the flow rate calculation section 16 inputs a flow rate pulse and state quantity signals such as temperature and pressure, and calculates a common flow rate of the instantaneous flow rate Qm and the integrated flow rate Q. Here, the instantaneous flow rate Qm is _{Qm = a × f × K H} × K T × 3600 (l / h: liter / hour) ... (1) accumulated flow rate Q is _{Qm = a × Ip × K H} × K T (l : Liter) (2) where a: meter coefficient of flow pulse (1 / p: liter /
Pulse) f: frequency of flow pulse (Hz) _KH : correction conversion coefficient _KT : unit conversion coefficient Ip: number of inlet pulses.

The correction conversion coefficient K _H has a different value depending on the instrumental error correction of the flow meter and the purpose of correction when obtaining the instantaneous weight flow rate of steam. These coefficients are stored in the RAM 8, and the flow rate calculation such as temperature correction and temperature pressure correction, etc., which are obtained by using the common flow rate calculation program shown in the equations (1) and (2) and the common flow rate calculation results. The program of the correction operation formula that can be corrected by the heater is stored in the ROM 7.

The IC card 12 is provided with the above-mentioned flow rate calculating section 1.
6 and the hardware such as the A / D converter can be operated independently of each other, and are determined according to the purpose.
2a is provided with a calibration function for calibrating the input / output relationship of hardware such as the A / D converter 3,
The IC card 12b is provided with a function of accessing a correction calculation formula for obtaining a desired flow rate signal from the ROM 7 or a calculation formula specified from the outside, and the IC card 12c is provided with an input to the correction calculation formula. It has a function of giving parameters to be set, and is determined by the specifications of the user.

First, I having a calibration function
An operation example of the C card 12a will be described. The memory content of the IC card 12a in which the calibration program is stored by inserting the IC card 12a into the flow rate calculator and driving the IC controller 13 is arranged below the memory area A of the ROM 7 which has been fixed. Is allocated to the EEPROM in the memory area B, and initialization is started when the allocation is completed.
The calibration program stored in a is executed.

In the calibration of the A / D converter of the conventional flow rate calculator shown in FIG. 3, when the correction to be applied is changed, the correction calculation formula is replaced each time according to the given specification. However, the second embodiment aims to solve this problem and to make it simple and easy for anyone to calibrate.

Embodiment 2 (corresponding to claim 2) FIG. 2 is a block diagram for explaining an example of embodiment 2, in which 16 is a switch SW, 18 is an external reference power supply, and G is an amplifier. , The parts having the same function as FIG.
The same reference numerals as in FIG. 1 are used. Although only the internal reference power supply 14 is shown in FIG. 2, the operation of the external reference power supply 18 is omitted because the operation is the same in the case of the external reference power supply 18.

The illustrated A / D converter 3 is, for example, an analog signal having a current input of 4 to 20 mA, an input terminal of the A / D converter 3 having a current input of 4 to 20 mA to a voltage input of 1 to 5 V. A 250 Ω reference resistance (not shown) for conversion is connected and treated equivalent to an analog input converter of 1 to 5 V. When the temperature signal is obtained by a three-wire temperature resistance method, a reference resistance corresponding to the resistance value of the temperature resistance wire is input and converted into a voltage.

The internal reference voltages 14 and 15 have a voltage accuracy of ±
Within 0.1%, temperature drift is ± 10ppm / ° C or less, temperature influence is small and aging is negligible
For example, it is composed of an internal reference power supply 14 of 1V and an internal reference power supply 15 of 5V. When the output of the A / D converter 3 with respect to the input of the 1 V internal reference power supply 14 is
Assume that it is 0. When the switch SW17 is connected to the internal reference power supply 14 via the (I / O) 4 according to a command from the CPU 6, the reference 1V voltage is input to the A / D converter 3 via the amplifier G. It is assumed that the data has been converted to digital data. If the digital value 510 is within the reference error range, the CPU 6 reads and stores the digital value 510, and stores the ratio 1.02 with respect to the theoretical digital value 500.

The CPU 6 switches the switch SW17 to the input terminal 2 side via the (I / O) 4 to divide the analog signal input to the A / D converter 3 by 1.02, thereby obtaining an internal signal. An accurate digital signal corresponding to the accuracy of the reference power supply can be obtained. The same applies to the internal reference power supply 15.

If the internal reference power supplies 14 and 15
If the reliability of the voltage accuracy is uncertain, an external reference power supply 18 which is considered to be highly reliable is connected between the terminals 2 and 2, and the external reference power supply 18 and the internal reference power supply 14 are input. The count value can be corrected based on the obtained digital data ratio.

Based on the same concept, the current output is 4 to 2
In the case of the D / A converter 9 of 0 mA, the output current is 250Ω
The voltage value converted by applying the reference
It is also possible to feed back to the input side of the / D converter 3 to calibrate the D / A converter 9.

As described above, the calibration program of the IC card 12a is stored in the E of the memory area B of the ROM 7.
Although assigned to the EPROM, the IC card 12a
Is changed, calibration is sequentially performed from PIO (Programmable IO) (1) to PIO (n) according to a procedure determined in the EEPROM.

By performing calibration using the IC card 12a, it is possible to cope with application of an application IC card 12b described later. However, the calibration IC card 12a
Can adjust (I / O) 4 independently of the application IC card 12b. Therefore, even after the application IC card 12b is inserted, the calibration can be performed by the calibration IC card 12a.

IC card 12b for application
Is a program for accessing, via the CPU 6, a program for obtaining a flow signal according to purposes such as temperature correction of a liquid flow rate, temperature and pressure correction of a gas flow rate, and weight flow rate correction of steam. IC card for setting
This is for designating parameters such as a state quantity to be input to a correction operation expression by the IC card 12b for application.

In the flow rate calculator according to the present invention, when the hardware calibration is completed by the calibration IC card 12a, the hardware can accept any IC card request. Conversely, after inserting the application IC card 12b, the calibration IC card 12a may be inserted. That is, each of the calibration IC card 12a, the application IC card 12b, and the parameter setting IC card 12c may be inserted. Independent, not dependent. Therefore, by inserting the IC card 12b for an application that accesses a correction operation formula determined according to a request such as temperature correction or steam weight correction into the flow operation device, a flow operation device suitable for the purpose can be obtained.

Further, by having the calibration IC card 12a for adjusting hardware as described above, application software corresponding to various types of arithmetic expressions can be added without concern for hardware. . Further, a wide range of applications can be expanded, such as creation of a maintenance IC card combining the calibration IC card 12a and the application IC card 12b, and an IC card for trend management.

[0035]

As apparent from the above description, the present invention has the following effects. (1) Effects corresponding to the first aspect: a software function for setting a flow rate correction operation and a parameter, which is a use purpose of the flow rate calculator, and a heart wear device for adjusting an A / D converter of the flow rate calculator, etc. Since it is configured separately using an IC card, a wide range of application software can be added without worrying about hardware, and it is possible to quickly respond to various flow rate calculations. (2) Effect corresponding to claim 2: The input / output of the assembled hardware is stored as a ratio with a reference provided inside the flow rate calculator, and the input / output of the hardware is corrected by the stored value of the ratio. In this way, trim adjustment is not required, and the calibration performed at the time of delivery can be performed on site without returning to a factory equipped with adjustment equipment. Therefore, anytime, anyone can perform accurate calibration.

[Brief description of the drawings]

FIG. 1 is a block diagram for explaining an embodiment of a flow rate calculator according to the present invention.

FIG. 2 is a block diagram illustrating an example of a second embodiment;

FIG. 3 is a block diagram for explaining a configuration of a conventional flow rate calculator.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Input terminal of a flow rate pulse, 2 ... Input terminal of a state quantity signal, 3 ... A / D converter, 4 ... I / O, 5 ... Bus, 6 ... C
PU, 7 ROM, 8 RAM, 9 D / A converter, 1
0: output terminal of the corrected flow pulse, 11: output terminal of the corrected flow signal, 12: IC card, 13: IC
Controller, 14, 15: internal reference power supply, 16: flow rate calculation unit, 16: switch SW, 18: external reference power supply, G
…amplifier.

Claims (2)

(57) [Claims] 1. A target correction arithmetic expression is selected from a number of stored correction arithmetic expressions, and a flow rate pulse of gas or liquid and a state quantity signal such as temperature and pressure are input to the selected correction arithmetic expression. In a flow rate calculator that calculates and outputs a flow signal of a predetermined level in a reference state, an application setting function of selecting the target correction formula, a parameter setting function of setting parameters of the selected correction formula, and A calibration setting function for converting a target flow signal into a flow signal of a predetermined level is independently configured so as to be non-interfering with other functions, and each of the setting functions is provided to an IC card. A flow rate calculator. 2. The conversion when the calibration setting is input to an internal reference power supply built in the flow rate calculator or an external reference power supply installed outside the flow rate calculator to a converter to be adjusted. The flow rate calculator according to claim 1, wherein a value of a ratio between the output of the vessel and the reference power source is stored, and a correction operation is performed based on the stored value of the ratio.