JP2612725B2 - Display device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device suitable for use as a display device of a monitoring device such as a factory facility.

[Summary of the Invention]

The present invention compares an input value with a set reference value, and when the input value is equal to or greater than the reference value, or when the input value is equal to or less than the reference value, this state can be displayed while displaying the input value. And a switch for retrieving and displaying a reference value without setting the display mode to the reference value setting mode.

[Conventional technology]

In recent years, microcomputers (hereinafter referred to as microcomputers)
Digital instruments equipped with are popular. In this type of digital instrument, calculated values, measured values, set values, etc.
(Liquid crystal display) or other display with numerical values.

By the way, in this type of apparatus, there is an apparatus that sets an upper limit or a lower limit of an input range or an output voltage, and monitors an input or an output by comparing the set value with the set value. In such a case,
It is necessary to display input values such as calculated values and measured values, and to display set values.However, if both displays are performed in separate spaces, contrary to miniaturization of digital instruments, the display characters will be reduced, It will be hard to see.

Therefore, in general, a single display is commonly used, and the mode is switched between the display mode of the input value and the setting mode of the comparison reference value. In this case, in the setting mode, the set value is displayed on the display and the set value can be changed.

[Problems to be solved by the invention]

However, when a single display is commonly used by mode switching as described above, there is no way to know whether the display value is larger or smaller than the set value in the input value display mode. The present invention seeks to provide a display capable of simultaneously recognizing an input display value and a lower limit value and a lower limit value of a reference set value.

In addition, it is necessary to call and confirm the set value. At this time, conventionally, the mode is switched to a reference value setting mode by mode switching means such as a switch to display the set value on a display.

However, the set value can be changed in the reference value setting mode. For this reason, if the setting mode can be set simply as a means for confirming the setting value, there is a risk that the setting value may be falsified by an outsider.

An object of the present invention is to provide a display device capable of avoiding the above disadvantages.

[Means for solving the problem]

Display means (3) for digitally displaying the upper limit value and lower limit value of the input value and the reference set value, and upper and lower limit value setting means (15) (16) capable of setting the upper limit value and the lower limit value of the reference set value
(17) and comparing means (22) and (23) for comparing the input value with the upper limit value and the lower limit value of the reference set value, and the comparing means (3) when the input value is displayed on the display means (3). 22) Based on the comparison output of (23), when the input value exceeds the upper limit of the reference set value, the upper half of the digital display character of the input display value blinks, and when the input value falls below the lower limit, the lower half of the digital display character Is made to blink.

[Action]

For example, when the input value is larger than the set reference value, for example, the upper half of the character of the input value displayed on the display means blinks and is displayed. When the input value is small, the lower half of the display character of the input value flashes and is displayed.

Then, when the switch means (8) is pressed, a set reference value is displayed on the display means (3) instead of the input value. However, at this time, since the mode is not the setting mode, the reference value cannot be changed. Therefore, even if there is a switch means (8) for calling the reference value, the reference value is not changed due to mischief.

〔Example〕

One embodiment of the present invention will be described below with reference to the drawings.

The example described below is an example in which the program contents and the like are not easily changed particularly by an outsider.

That is, for example, a digital instrument equipped with a microcomputer uses a push button switch, a rotary switch, and a digital switch provided on an operation panel surface in order to freely program a handling input signal range, an instruction value, an output voltage, and the like on a user side. The input operation has been performed.

However, the fact that a switch such as a push-button switch for inputting a program is provided on the operation panel means that the digital instrument is located at a position where it can be easily operated by an outsider unrelated to the program operation on the digital instrument. Means that. Therefore, there is a concern that the contents of the program may be easily changed by the outsider touching the switches.

Therefore, in this example, magnetic sensing means for converting a change in the magnetic flux into an electric signal is provided on or near the surface of the housing of the digital instrument, and information is input by externally bringing the magnetic flux source close to the magnetic sensing means. Thus, switches such as program input are not exposed to the outside, so that input operations by outsiders can be prevented.

FIG. 2 shows the appearance of the digital instrument of this example.
FIG. 2A is a perspective view of the digital instrument as viewed from the front panel side, and FIG. 2B is a view for explaining how to input information.

In FIG. 2, (1) shows the housing of the digital device as a whole, and (2) shows a front panel. In this example, the front panel (2) includes a liquid crystal display (3).
And a display signal from a microcomputer (not shown) provided in the housing (1) is supplied to the liquid crystal display unit (3) via a display drive circuit to display measured values and calculation results. Done.

In the case of this example, marks (4M) and (5M) as shown in FIG. B are provided on the left and right side surfaces of the liquid crystal display section (3) of the front panel (2). Then, in the housing (1) on the rear side of the front panel (2) corresponding to the positions of the marks (4M) and (5M), a magnetically sensitive element, in this example, a lead is provided in the vicinity of the panel (2). Switches (4) and (5)
Are provided as shown by dotted lines in FIG. The reed switches (4) and (5) are connected to a microcomputer in the housing (1) via an interface (not shown), and the reed switches (4) and (5) are connected to the microcomputer by turning on and off. Information can be entered. The marks (4M) and (5M) indicate the positions of the reed switches (4) and (5).

The mark (4M) (5M) can also serve as, for example, a company mark or other display.

Using the marks (4M) and (5M) as a mark, information is input by the reed switches (4) and (5) as follows.

That is, as shown in FIG. 2B, a person who inputs information holds a magnetic field source, in this case, a permanent magnet (7) in his hand (6) and brings it close to the mark (4M). Then, an induced current flows through the coil of the reed switch (4),
The reed switch (4) turns on. Next, when the permanent magnet (7) is moved away, the reed switch (4) returns to off. Similarly, the reed switch (5) can be turned on / off by moving the permanent magnet (7) closer to or farther away from the reed switch (5), and information can be input.

At this time, the mark (4M) (5
By attaching a soft material such as rubber to the portion on the side close to M) or by surrounding the soft material with the soft material, it is possible to prevent the front panel and the liquid crystal surface from being damaged.

In this example, the reed switch (4) functions as a mode switching means, and each time the reed switch (4) is turned on, the mode can be cyclically changed to a plurality of modes selectable by the digital instrument. . If the reed switch (4) is turned on for a certain time or more, the mode is automatically changed at a predetermined speed cyclically until the reed switch (4) is turned off.

In the reference value setting mode, the reed switch (5) functions as a set value changing means, and can change the set value by one step each time the reed switch (5) is turned on. When the reed switch (5) is turned on for a certain period of time or more, the set value can be automatically changed at a predetermined speed, and when the reed switch (5) is turned off, the set value when the reed switch (5) is turned off is set. become. And the second
In the figure, reference numeral (8) denotes a non-locking type push button for calling a set reference value. When the push button (8) is pressed in a display mode of an input value such as a measured value or a calculated value on a display unit, The reference value set in place of the display value of the input value is displayed on the display unit (3) only while the button is pressed.
At this time, the setting value cannot be changed even if the reed switch (5) is turned on when the button (8) is pressed while the mode remains the input value display mode.

In this case, the reference value can be set to an upper limit value and a lower limit value, and can be changed to an upper limit value setting mode and a lower limit value setting mode by mode selection. Each time the push button (8) is pressed, the upper limit value and the lower limit value are alternately called and displayed. At this time, for example, "UP" is displayed on the display unit (3) when the value is the upper limit, and "DO" is displayed when the value is the lower limit.
WN "or nothing at all,
A distinction is made as to which setting is being displayed.

In this example, when the input value becomes larger than the set upper limit in the input value display mode, as shown in FIG. 3A, the upper half of the numerical character of the display input value of the display unit (3) is displayed. The part flashes to show it. When the input value is smaller than the set lower limit, the lower half of the numerical character of the display input value on the display unit (3) blinks as shown in FIG. I do.

The above operation is controlled using a microcomputer, but it can also be configured in hardware as follows.

FIG. 1 is a block diagram of one embodiment of the present invention, in which an input pulse cycle is measured and displayed on a display unit (3).

In the same figure, (10) is a mode signal forming means, each time the reed switch (4) is turned on by the magnetic field source,
The signals IN, UP, and DW for sequentially and cyclically switching the mode among three modes of the input value display mode, the upper limit value setting mode, and the lower limit value setting mode are obtained. That is, only the signal IN becomes "1" in the input value display mode, only the signal UP becomes "1" in the upper limit setting mode, and only the signal DW becomes "1" in the lower limit setting mode. .

In the input value display mode, the cycle measuring means (11) operates by the signal IN, the cycle of the input pulse from the input terminal (12) is measured, and the measurement result is supplied to the input terminal A of the selector (13). You. The selector (13) is in the input display mode, and selects the input signal on the input terminal A side when the set value calling push button (8) is not pressed. Therefore, at this time, the measurement result is supplied to the liquid crystal display unit (3) via the display drive and the control means (14), and the measurement result is displayed with a numerical value.

In the upper limit setting mode or lower limit setting mode,
Since one of the signals UP or DW becomes "1", the set value output means (15) operates. The output means (15) changes the set value each time the reed switch (5) is turned on or while the reed switch (5) is turned on. The output set value from the output means (15) is supplied to an upper limit register (16) and a lower limit register (17). Signal UP to upper limit register (16)
Is supplied and this register (1
The output set value is written to 6). Further, the signal DW is supplied to the lower limit register (17), and the output set value is written to the register (17) in the lower limit setting mode.

The upper limit written in the upper limit register (16) is input to the input terminal A of the selector (18), and the lower limit register (17)
Is written to the input terminal B of the selector (18).
Supplied respectively. The selector (18) is controlled by a select signal from the upper and lower limit switching means (19). The switching means (19) is supplied with signals UP and DW. A signal for switching the selector (18) to the input terminal A side when the signal UP is "1" and the selector (18) to the input terminal B side when the signal DW is "1" from the switching means (19). Is obtained.

Accordingly, the selector (18) obtains the upper limit value from the register (16) in the upper limit value setting mode, and obtains the lower limit value from the register (17) in the lower limit value setting mode.
The output of the selector (18) is input terminal B of the selector (13).
Supplied to

In the upper limit or lower limit setting mode, one of the signals UP and DW becomes “1”, which is supplied as a select signal to the selector (13) via the OR gate (20). Selector (1
3) is always switched to the input terminal B.

Therefore, the set upper limit value or lower limit value is supplied to the display unit (3) via the display drive and the control means (14) and displayed.

Next, when it is desired to call the upper limit or the lower limit in the input value display mode and display it on the display unit (3), the push button (8) is pressed. Then, from the reference value calling means (21), while the push button (8) is pressed and turned on, a signal RD of "1" is obtained and the push button (8) is turned on. A signal TG that inverts the state of “1” and “0” every time is obtained.

The signal RD is supplied to the selector (13) via the OR gate (20). Therefore, even when the selector (13) is in the input value display mode, the selector (13) is switched to the input terminal B only while the signal RD is "1", that is, while the push button (8) is being pressed. Select output. At this time, since the signals UP and DW are both “0”, the same signal as the signal TG is obtained from the switching means (19), whereby the selector (18) is controlled, and the selector (18) is pressed by the push button ( 8) The upper limit value and the lower limit value are alternately selected each time is turned on.

Therefore, when the push button (8) is pressed, for example, an upper limit value is displayed on the display unit (3) instead of the cycle measurement value while the push button (8) is pressed, and when the push button (8) is pressed again, the push button (8) is pressed. During this time, the lower limit is displayed on the display unit (3).

At this time, since the signals UP and DW are both "0" and the mode is not the set value mode but remains in the input value display mode,
The set value cannot be changed and will not be tampered with.

Next, in the input value display mode, when the measured value becomes equal to or more than the upper limit value or becomes equal to or less than the lower limit value, the measured value is displayed as shown in FIGS.

That is, the output of the period measuring means (11) is
2) and (23) supplied. In addition, the upper limit register (1
The upper limit value from 6) is supplied to the comparing means (22), and the lower limit value from the lower limit register (17) is supplied to the comparing means (23), and are compared with the cycle measurement value. The comparison means (22) obtains a comparison output CU which becomes, for example, "1" when the cycle measurement value becomes equal to or more than the upper limit value, and obtains the comparison output CU from the comparison means (23) when the cycle measurement value falls below the lower limit value. A comparison output CD that becomes "1" is obtained. These comparison outputs CU and CD are supplied to the display drive and control means (14). And the output CU
Is "1", as shown in FIG. 3A, the upper half element portion of the "day" shaped segment of the displayed numerical value of the cycle measurement result flashes. When the output CD is "1", the lower half element portion of the "day" character segment of the display value of the cycle measurement result blinks as shown in FIG. In this blinking control, the drive output of the upper half element and the lower half element of the "day" shaped segment are supplied to each element via the blinking control circuit, respectively.
This can be performed by controlling each blinking control circuit with the comparison output CU and CD.

Although the above example is an example in which the display means is a liquid crystal display, it is needless to say that a discharge display tube or another display can be used.

〔The invention's effect〕

As described above, according to the present invention, in the input value display mode, when the input value exceeds the set value, the upper half or the lower half of the numerical character of the input display value is displayed by blinking.
The display means can monitor that the input value has exceeded the set value.

Further, according to the present invention, since the button switch for retrieving the set value and displaying the set value on the display means is provided without changing the input value display mode to the set value mode, the set value can be appropriately called, and When calling, there is no fear that the set value is changed due to mischief or the like.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing an appearance of an embodiment of the present invention, and FIG. 3 is a diagram for explaining an example of the present invention. (1) is a housing, (2) is a front panel, (3) is a liquid crystal display unit, (4) and (5) are reed switches, (7) is a permanent magnet, and (8) is a finger-head pressing type push button switch. ,
(10) is a mode signal forming means, (13) is a selector, (1)
4) is a display drive and control means, (15) is set value output means, (16) and (17) are upper limit and lower limit registers, and (22) and (23) are comparison means.

Claims (1)

(57) [Claims] A display means for digitally displaying an input value and an upper limit value and a lower limit value of a reference set value; an upper limit value and a lower limit value setting means capable of setting an upper limit value and a lower limit value of the reference set value; And a comparing means for comparing the upper limit value and the lower limit value of the reference set value. When the input value is displayed on the display means, based on a comparison output of the comparison means, the input value is set to a reference set value. A display device characterized in that the upper half of the digital display character of the input display value flashes when the upper limit value is exceeded, and the lower half of the digital display character flashes when the lower limit value is exceeded.