JPH04125682A - Digital display device - Google Patents

Abstract

PURPOSE:To make main parts of a digital display device common by using an input signal converting card on which a signal converting part converts plural kinds of input signals into common standardized signals and outputs them, it mounted. CONSTITUTION:The digital display device is equipped with an input signal converting card 6 on which the converting part which converts the plural kinds of input signals into the common standardized signals and outputs them, an outputting part which outputs attribute data, an A/D converter 10 which converts the standardized signals inputted through a connector 7 into digital signals, digital display device 12 which displays the counted value of the A/D converter 10, a controlling part 11 which switches the decimal point position of the digital display device 12. Then, the input signal converting card 6 is connected with the connector 7, so that the scaling of the A/D converter 10 can be automatically operated, and the decimal point position of the digital display device 12 can be switched. Thus, the main pats of the device can be made common, and the function of the device can be easily changed only by exchanging the input signal converting card 6 corresponding to measured signals.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a digital display device, and the present invention relates to a digital display device.
This invention relates to scaling control of a device incorporating a D converter.

<Prior Art> As an alternative to conventional mechanical meters, digital display devices that electronically display measured values digitally are widely used.

FIG. 5 is a block diagram showing an example of such a conventional device. In FIG. The signal is converted and applied to the A/D converter 3. A/
The digital signal converted by the D converter 3 is applied to a multiplier 4 and scaled to be equal to the value of the measurement signal applied to the input terminal 1. The display 5 has a plurality of digits and digitally displays the result of the calculation by the multiplier 4. Note that the decimal point of the display 5 is displayed as a fixed light at a predetermined position depending on the input range of the measurement signal applied to the input terminal 1.

By the way, in such a conventional digital display device, the scale data and decimal point position of the multiplier 4 are manually set individually at the time of assembly so that it operates as a single-function device suitable for a single measurement signal level to be measured. It had been.

<Problems to be Solved by the Invention> However, according to such a configuration, in order to determine multiple types of measurement signals, multiple digital displays that are combined and set to match each measurement signal are required. Equipment must be prepared, which is uneconomical.

Furthermore, since the scale data and decimal point position of the multiplier 4 are manually set during assembly, there is a risk that a setting error may occur.

Furthermore, when the type of measurement signal is changed, it is difficult for Usar to change the digital display device to match the changed measurement signal.

The present invention has focused on such problems, and its purpose is to provide a digital display device with a high degree of freedom in which the main parts of the device can be shared.

<Means for solving the problems> The present invention solves these problems by providing a signal conversion section that converts and outputs a plurality of types of input signals into a common unified signal, and an attribute that outputs card-specific attribute data. Multiple types of input signal conversion cards equipped with data output units, connectors to which these input signal conversion cards can be attached and removed, and a unified signal input through the connectors that is converted into a digital signal based on a variable frequency clock. Counting type A/
A/D converter, a multi-digit digital display that displays the count value of this A/D converter, and an A/D converter based on the attribute data input via the connector.
It is characterized by comprising a control section that switches the clock frequency of the D converter and the decimal point position of the digital display.

<Function> By connecting the input signal conversion card to the connector,
The A/D converter is automatically scaled and the decimal point position of the digital display is also switched.

This allows the main parts of the device to be shared, and the functions of the device can be easily changed by simply replacing the desired input signal conversion card that corresponds to the measurement signal.

<Example> Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. In FIG. 1, an input signal conversion card 6 is attached to and detached from a connector 7, and there are a plurality of types of input signal conversion cards 6 corresponding to each of a plurality of types of measurement signals. It is provided. Each of these cards 6
As shown in Figure 2, input signals of any one of multiple types, such as DC voltage, DC current, AC voltage, and AC current, are connected to a common unified signal such as 0 to 1 V or -] to 0 to 1 V. A signal conversion section 8 that converts and outputs a signal, and an attribute data output section 9 that outputs card-specific attribute data such as scaling information and decimal point position information are installed. The connector 7 has a counting type A/D that converts the unified signal input from the card 6 into a digital signal based on a variable frequency clock.
A converter 10 is connected to the converter 10, as well as a control section 12 that switches the clock frequency of the A/D converter 10 and the decimal point position of the digital display 11 based on attribute data input from the card 6. Digital display 11
is for displaying the count value of the A/D converter 10, and is provided with a plurality of display digits (for example, four digits).

FIG. 3 is a block diagram showing a specific example of the A/D converter 10 used in FIG.
400,500,600,750800,1000,1
200, 1500, 2000, 2500, 3000) can be selected. Although the A/D converter 10 is basically a double integration type, it is constructed so that scaling can be performed by dividing the clock frequency. That is, it is assumed that the tally clock generator 13 outputs 60,000 pulses at full scale.The tally clock of this clock generator 13 is branched into a binary counter 14 and a ternary counter 15. The output signal of the advance counter 15 is input to a control circuit 16 that sets the gate time via a changeover switch S1.The control circuit 16 includes an integrator 17.
Also added is the output signal of a comparator 18 which compares the output signal of 1 with the zero level. Note that the non-inverting input terminal of the operational amplifier constituting the integrator 17 is grounded, the input voltage and the reference voltage are applied to the inverting input terminal via the resistor R and the changeover switch S0, and the voltage is applied between the inverting input terminal and the output terminal. is connected to capacitor C.

The clock passing through the control circuit 16 is clocked by a binary counter 19.
and one fixed contact "1" of each of the changeover switches 82 to S4. The output signal of the binary counter 19 is applied to the other fixed contact "0" of the changeover switch S2. The output signal of the changeover switch 2 is applied to a binary counter 20. The output signal of the binary counter 20 is sent to the other fixed contact r of the changeover switch S3.
□.

has been added to. The output signal of the changeover switch 3 is applied to a quinary counter 21 and also to one fixed contact "1" of the changeover switch S5. Quintal counter 2
The output signal of 1 is output from the other fixed contact ``0'' of the changeover switch S4.
” has been added.

The output signal of the changeover switch is applied to the other fixed contact "0" of the changeover switch S5. The output signal of the changeover switch S5 is applied to the binary counter 22 and also to one fixed contact "1" of the changeover switch S6. The output signal of the binary counter 22 is applied to the other fixed contact "0" of the changeover switch S6. changeover switch,
The output signal is applied to the quinary counter 23 and to one fixed contact "1" of the changeover switch S7. The output signal of the quinary counter 23 is applied to the other fixed contact "0" of the changeover switch S7. The output signal of the changeover switch 7 is applied to a counter 24. The output signal of this counter 24 is then added to the display 12 and displayed digitally.

Each changeover switch 8 of the A/D converter 1o having such a configuration
The relationship between the switching combinations of the movable contacts 1 to S7 and the pulses applied to the counter 24 is as shown in FIG. In addition,
FIG. 4 shows the number of pulses actually applied to the counter 24 when the full scale is 60,000 pulses. For example, if you want the full scale to be 400, change the fixed contacts of the changeover switches 81 to S7 to ro-0-1. -0-0-0
-OJ and if you want to set the full scale to 3000, set the fixed contacts of the changeover switches 81 to S7 to [l-0-
O-0-1-0-I Switch to J.

Switching control of these changeover switches S, -S7 is performed by the control unit 11 shown in FIG. 1 based on the attribute data of the input signal conversion card 6 inputted via the connector 7. It also controls switching of the decimal point position on the digital display 12 as shown in FIG.

With this configuration, simply by inserting the desired input signal conversion card 6 corresponding to the measurement signal into the connector 7, the predetermined scaling setting and decimal point position switching will be performed automatically. Setting errors that occur when setting manually can be prevented.

Also, when measuring multiple types of measurement signals or changing the type of measurement signal, prepare one digital display device and replace only the input signal conversion card that is compatible with each measurement signal. It is also economical because there is a high degree of freedom regarding the type of measurement signal.

Furthermore, since a part of the converted data is truncated during display, the display becomes more resistant to noise and the like.

<Effects of the Invention> As described above, according to the present invention, it is possible to realize a digital display device with a high degree of freedom in which the main parts of the device can be shared, and the practical effects are great.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a block diagram showing the details of the input signal conversion card used in Fig. 1, and Fig. 3 is an A/D converter used in Fig. 1. 4 is an explanatory diagram of scaling in the apparatus shown in FIG. 1, and FIG. 5 is a block diagram showing an example of a conventional digital display device. 6...Input signal conversion card, 7...Connector, 8.
...Signal converter, 9...Attribute data output section, 10...
- A/D converter, 11...control unit, 12...digital display. No.! Figure Figure Figure Figure

Claims (1)

[Scope of Claims] A plurality of types of input signal conversion cards equipped with a signal conversion section that converts and outputs a plurality of types of input signals into a common unified signal and an attribute data output section that outputs card-specific attribute data; A connector to which an input signal conversion card can be installed and removed, and a counting type A/D converter that converts the unified signal input through the connector into a digital signal based on a variable frequency clock.
A/D converter, a multi-digit digital display that displays the count value of this A/D converter, and an A/D converter based on the attribute data input via the connector.
1. A digital display device comprising: a control section that switches the clock frequency of a D converter and the decimal point position of a digital display.