JPS60154115A - Testing device for industrial instrument - Google Patents

Abstract

PURPOSE:To perform good-operability setting which uses a setter and good-precision setting selectively by selecting the digital display of a set value set by the setter or the digital display of conversion from an output air pressure signal to an electric signal by switching. CONSTITUTION:When setting operation is carried out with the setter 1, switches 12a and 12b are connected to sides a1 and a2 respectively. In this state, the common terminal of the changeover switch 12b is grounded through the terminal a2, so it is held at a low level. Its low signal is inputted to a CPU2 through a port 22, and means that the set value inputted to a display device 4 from the setter 1 is displayed on the display device 4. Therefore, the ten-key of the setter 1 is operated in this state to input a numeral corresponding to the air pressure signal to be set, and this digital value is inputted to the CPU2 from the setter 1 through a port 7 and the set value is set through a data bus 5 and a port 8 to and displayed on the display device 4 under the control of the CPU2.

Description

Detailed Description of the Invention (a) Industrial Application Field This invention provides an input signal of air pressure to an industrial instrument that receives the air pressure signal as input, and outputs it (air pressure or electric signal).
This invention relates to industrial instrument testing equipment that measures and performs accuracy tests.

(B) Prior Art In general, in industrial instrument testing equipment, the pneumatic pressure signal to be output is sometimes set digitally. Conventionally, industrial instrument test equipment with digital setting method uses a dial to make settings, generates a voltage corresponding to the setting dial, and converts this to air pressure, and others that use a microprocessor for control and use a numeric keypad. Enter the settings and
There are devices that convert this set value into D/A and then convert it into air pressure.

These conventional industrial instrument testing devices perform settings digitally, so the setting input is accurate and easy to operate, but the pneumatic setting accuracy is mostly determined by the accuracy of the electro-pneumatic converter.
The drawback is that highly accurate settings are not necessarily possible.

This is because when a digital signal corresponding to the setting value input from the setting device is D/A converted and then electro-pneumatically converted, the accuracy of the pneumatic signal is affected due to the offset voltage and gain of the amplifier of the electro-pneumatic converter. It is for falling.

(c) Purpose The purpose of the present invention is to eliminate the drawbacks of the above-mentioned conventional device,
It is an object of the present invention to provide an industrial instrument testing device that can selectively perform settings with good operability using a setting device such as a numeric keypad, and settings with high accuracy.

(d) Configuration In order to achieve the above object, the industrial meter testing device of the present invention includes a variable voltage source and a D/A converter that converts a setting signal from a setting device into an analog signal and inputs it to an electro-pneumatic converter. The vessel and
a switching means for selectively connecting the variable voltage source to an input of the electro-pneumatic converter; a pneumatic converter for converting a pneumatic signal from the electro-pneumatic converter into an electric signal; and a pneumatic converter for converting the electric signal into a digital signal. In response to the connection of the A/D converter, the variable voltage source and the electro-pneumatic converter by the switching means, the
It is characteristically equipped with a control means for displaying the output of the /D converter on a display.

(E) Examples The present invention will be explained in more detail with reference to Examples below.

The drawing is a block diagram of an industrial instrument testing device showing one embodiment of the present invention.

In the drawings, reference numeral 1 denotes a setting device that digitally sets the air pressure signal, and specifically includes a numeric keypad and the like. 2 is a CPU, which executes various control calculations; A memory 3 is provided to store setting data input from the setting device 1 and various calculation data calculated by the CPU 2. Reference numeral 4 denotes a digital display on which setting values input from the setting device 1 are displayed. The CPU 2 and memory 3 are connected to a setting device I via a data bus 5 and an address bus 6 via ports 1 to 7, and similarly connected to a display device 4 via a port 8.
is further connected to D/A converter 1 via baud 1-9.
0, is connected to the A/D converter 19 via the port 20, and is connected to the common terminal C2 of the switch 12b via the port 22, and is configured to exchange various data with each circuit section. ing.

The output of the D/A converter 10 is connected to the amplifier 14 via the terminal a1 of the changeover switch 12a and the common terminal cl, and the output signal voltage of the amplifier 14 is connected to the piezoelectric flapper 1.
5.

16 is a nozzle, and 17 is a pilot valve, into which supply pressure is input and output pressure is derived. Further, the output air pressure is converted into an electric signal by a pressure sensor (pneumatic converter) 18, and the output end of the pressure sensor 18 is connected to one end of the input of the amplifier 140, and is also connected to the input end of the A/D converter 19. ing.

On the other hand, a variable voltage source 11 is connected between the terminal b1 of the changeover switch 12a and the ground. Further, a power source 21 is connected between the terminal b2 of the changeover switch 12b and the ground, and the terminal a2 of the changeover switch 12b is connected to the ground. Further, the changeover switches 12a and 12b are configured to perform switching operations in conjunction with each other.

Note that the circuit section A includes an amplifier 14 and a piezoelectric flapper 15.
, the electro-pneumatic converter A is composed of a nozzle 16 and a pilot valve 17, but the electro-pneumatic converter A may be composed of other components such as an electromagnetic flapper.

Further, the circuit section B shown in the drawings is a circuit section that is uniquely provided compared to the conventional industrial instrument testing equipment using a CPU.

Next, the operation of the industrial meter testing apparatus constructed as described above will be explained.

First, when performing a normal setting operation using the setting device 1, the switches 12a and 12b are connected to the al and a2 sides, respectively. In this state, the common α (H) of the changeover switch 12b is connected to the ground through the terminal a2, so it is in low level health.
This low signal is taken into U2 (Cl) through 22, and is a signal indicating that the setting value input from the setting device 1 should be displayed on the display 4. In this state, when the numeric keypad of the setting device 1 is operated and a value corresponding to the air pressure signal to be set is inputted, this digital value is imported from the setting device 1 to the CPU 2 via the boat 7. , the setting values are sent to the display 4 via the data bus 5 and the boat 8 under the control of the CPU 2 and displayed thereon. Furthermore, this setting value is converted into an analog signal by the D/A converter 10 via the boat 9, and is applied to the amplifier 14 via the terminal a1 of the changeover switch 12a and the common terminal C1. The voltage amplified by the amplifier 14 is then applied to the piezoelectric flapper 15. The displacement of the flapper due to the voltage applied to the piezoelectric flapper 15 and the back pressure of the air pressure supplied to the nozzle 16 via the viroft valve 17 stabilize when a balance is achieved, and an output air pressure corresponding to the applied voltage is derived. be done. This stabilization of the output air pressure is achieved by converting the output air pressure into an electrical signal by the pressure sensor 18,
This electric signal is fed back to the amplifier 14, and control is performed so that the set voltage finally applied to both input terminals of the amplifier 14 and the feedback voltage match.

In the manner described above, the output air pressure corresponding to the setting value set by the setting device 1 is derived.

Next, if you want to make more severe settings than the normal state, switch the selector switches 12a and 12b to the sole terminal b1.
．． Switch and connect to b2 side. By this switching, the voltage of the variable voltage source 11 is applied to the amplifier 1 via the terminal b1 and the common terminal c1.
4 is added to one end of the input. And the D/A mentioned above
The output air pressure corresponding to the voltage of the variable voltage source 11 is derived from the pilot valve 17 by the same operation as when the setting voltage from the setting device 1 is applied via the output of the converter 1o and the terminal a1. In this case, the output air pressure is determined by the pressure sensor ■
8 into an electrical signal, which is fed back to the other end of the input of the amplifier 14 to balance and stabilize the voltage from the variable voltage source 11 and the output air pressure, and converted into a digital signal by the A/D converter 19. be done. And boat 2
A signal corresponding to the output air pressure at that time is taken in from the data bus 5 to the CPU 2 via the data bus 5.

Note that in this state, the selector switch 12b is connected to the terminal b2 side, so the high level signal of the power supply 21 passes through the terminal b2, the common terminal C2, and the port 22, and is then connected to the data bus 5.
This high signal causes the CPU 2 to display on the display 4 the output air pressure value that has been taken in via the A/D converter 19 and the boat 20. This results in
Each time the value of the output air pressure converted into an instant electric signal is displayed on the display 4. Therefore, the setting operator can arbitrarily set the output air pressure by changing the voltage value of the variable voltage source 11 using the knob while looking at the display on the display 4. In this case, the output air pressure is immediately converted into an electrical signal by the pressure sensor 18 and displayed, so a very accurate output air pressure can be displayed on the display 4.
You can make accurate settings.

According to the industrial instrument testing device of the present invention, the digital display of the set value set by the setting device and the digital display made by immediately converting the output air pressure signal into an electrical signal can be selected by switching. Therefore, relatively rough settings are required, and it is possible to use settings that emphasize operability or setting accuracy as desired depending on the application, and is suitable for industries where various conditions and instruments must be tested. Very useful for instrument testing equipment.

[Brief explanation of the drawing]

The drawing is a block diagram of an industrial instrument testing device showing one embodiment of the present invention. 1: Setting device, 2: CPU. 4: Display device, 10: D/Δ converter, 11: Variable voltage source, 12a-12b: Changeover switch, 18: Pressure sensor (pneumatic converter), 19: A/D converter. Patent applicant Ha Shima Ritsu Seisakusho Co., Ltd. Agent Patent attorney Shigeru Nakamura

Claims (1)

[Claims] (1) A setting device that inputs the setting value of the air pressure signal to be output as a digital value, a display device that displays the setting value input with this setting device, and a D that converts the setting value from a digital signal to an analog signal. /A converter; and an electro-pneumatic converter that converts the analog signal into a pneumatic signal. a switching means for switching connection to the input of the converter, and an electric pneumatic signal from the electro-pneumatic converter (■
an A/D converter that converts the electric signal from an analog signal to a digital signal; and an A/D converter that converts the electric signal from an analog signal to a digital signal; , and control means for displaying the output of the A/D converter on the display.