JP2903563B2 - Operation panel contrast adjustment circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention digitally adjusts the contrast of a flat display on an operation panel by a control signal from a processing device including a microcomputer, and specially adjusts the contrast. The present invention relates to a contrast adjustment circuit for a flat display in an operation panel in which contrast can be adjusted using an existing switch on the operation panel without using a simple switch.

[Conventional technology]

Conventionally, as this type, for example, there is a type in which an operator operates a variable resistor using a volume knob and changes a voltage value input to a display in an analog manner to adjust contrast.

[Problems to be solved by the invention]

However, in the above-described method, a knob for adjusting the contrast of the flat display is disposed in front of the operation panel surface, so that a gap is formed, and there is a problem in terms of waterproofness, oil resistance, dust resistance, and the like. Occurs. In addition, if the contrast adjustment knob is placed on the back of the operation panel so as not to affect the waterproofness, oil resistance, and dust resistance, it will be difficult to adjust the contrast while checking the visibility. Problems arise.

[Means for solving the problem]

In order to solve the above-described problems, in the present invention, the operation panel is connected to an external control device via an interface bus or an input / output interface, and the operation panel surface includes a flat display and a transparent switch or a sheet-like operation switch equivalent thereto. In an operation panel configured and controlled by a computer, between the computer and the flat display,
A plurality of sets of contrast adjustment circuits each comprising a combination of a photocoupler and a resistor connected in parallel with the photocoupler are provided, and among the plurality of sets of contrast adjustment circuits,
By outputting a signal specifying a combination of contrast adjustment circuits to be operated from the computer, an adjusting means for adjusting the contrast by switching a voltage value input to the flat display in a plurality of stages is provided, wherein the transparent switch or the sheet-like operation is provided. By providing instruction information for contrast adjustment from the switch to the computer, the computer outputs a signal for specifying the combination of contrast adjustment circuits to be operated, corresponding to the instruction information, to the adjustment means from the computer. To do.

[Action]

By performing the contrast adjustment of the flat display on the operation panel through a processing device including a microcomputer, a signal for the contrast adjustment need only be given digitally. At this time, by using a transparent switch or a sheet-like operation switch equivalent thereto to provide a signal for contrast adjustment, it is possible to solve problems such as waterproofness, oilproofness, and dustproofness. In addition, if a switch or key arranged on the operation panel and used for another purpose is also used as a switch for contrast adjustment, there is no need to provide a special switch for contrast adjustment. There is no increase in size.

〔Example〕

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is an external view of an operation panel, FIG. 3 is a flowchart for explaining a contrast adjusting operation according to the present invention, and FIG. FIG. 5 is a flowchart for explaining the operation, FIG. 5 is a block diagram for explaining the relationship between the operation panel and an external device, and FIG. 6 is a system configuration diagram showing the operation panel.

First, FIG. 5 will be described. This indicates a connection relationship between the operation panel and an external device.
Is an external control device.

The external control device 2 is most often a programmable controller (sequencer), but may be an electronic device such as a microcomputer. The control device 2 controls the mechanical device 3 and controls the mechanical device 3 to be controlled.
Is connected to control elements such as a motor, a solenoid, a solenoid valve, and the like, which constitute a machine and a device, and a sensor by a control cable 5. The mechanical device 3 may be various devices such as a machine tool, a thermostat, an office machine, and a printing machine. The operation panel 1 according to the present invention and the external control device 2 are connected via a bus 4 such as a serial interface or an 8-bit input / output bus.

FIG. 6 shows a system configuration of the operation panel in FIG. In the figure, 6 is a microcomputer system as a CPU (central processing unit), 7 is a character generator (CG) for generating display characters, and 8 is a screen memory for storing graphics constituting the screen, functions of operation switches, and the like. (EEPR
OM) and 9 are data memories (RAM) for holding data received from an external control device, 10 is an internal bus, and 11 is an operation panel surface in which a display panel and operation switches (transparent switches) are integrated. Of these, 11a is used to indicate an operation switch, and 11b is used to indicate a display panel. The operation switch 11a may be a transparent switch disposed on the display panel or a switch disposed at a position different from the display panel, but is a sheet having excellent waterproof, oil-proof, and dust-proof properties like the transparent switch. It is desirable that the operation switch or the key be shaped like a letter. Reference numeral 12 denotes a key encoder (operates to input the operation output of the operation switch 11a and transmits the operation output to the microcomputer system 6 as encoding), 13 denotes a display control switch, 4 denotes an interface bus, and 14 denotes a screen to be displayed on the display panel 11b. A loader 2 for creating and setting the role of the operation switch 11a is a sequencer 2 as an external operation control device. A machine (see reference numeral 3 in FIG. 5) is connected to the end of the sequencer 2, and the operation procedure (program) of the machine is controlled by the sequencer 2. This sequencer 2
Reads the operation result of the operation switch 11a via the key encoder 12 and the microcomputer system 6, and issues a command to the microcomputer system 6 by issuing a command to the microcomputer system 6 to select and specify the screen data stored in the screen memory 8. An operation output is output to the aforementioned machine connected to the sequencer, and a command is issued to the microcomputer system 6 to display the display panel 11b.
Has a function of switching the display screen. 15 is a printer.

FIG. 1 shows a display panel 11 according to an embodiment of the present invention.
An example of a circuit for changing the contrast of b into eight levels is shown. SW1 to SW3 in the figure are switches used for adjusting the contrast, 16 (16a, 16b, 16c) is a photocoupler, and R1 is
R9 is a resistor, and S1 to S7 are signal lines (or signal itself).

By the way, in order to change the contrast of the display, the driving voltage of the display may be changed. Therefore,
The contrast can be changed by making the resistance between the drive power supply and the display 11b variable. Here, the photocoupler 16 and the resistors R1 to R3 are connected in parallel so that the microcomputer (CPU) 6 can control the contrast.

Here, when a high-level signal “H” is output from the CPU 6 to the signal line S1, no current flows to the input side of the photocoupler 16a, and the output side of the photocoupler 16a is opened,
The current does not flow through the photocoupler 16a but flows through the resistor R1, and a voltage drop occurs in the signal line S7 by the resistance R1. Due to the voltage drop, the contrast of the flat display 11b is reduced. In contrast, the signal line S1
When a low-level signal “L” is output from the CPU 6, a current flows to the input side of the photocoupler 16 a and the output side of the photocoupler 16 a is closed, and the current on the output side of the photocoupler flows to the photocoupler side. No voltage drop occurs on the signal line S7. Since the voltage drop does not occur, the contrast of the flat display 11b tends to increase.

As described above, there are two types of voltage states on the signal line S7 due to the output from the CPU 6 to the signal line S1, whereby the contrast of the flat display changes in two stages. Therefore, as shown in FIG. 1, such a system is connected to three systems, and the values of the resistors R1, R2, and R3 are set so as to satisfy, for example, R1 + R2 + R3> R1 + R2> R1 + R3>R1> R2 + R3>R2>R3> 0. If this is the case, the contrast can be changed in eight stages by the combination of the output signals S1, S2, S3 from the CPU 6.

Next, as a method of providing a signal for contrast adjustment to the CPU 6, this is performed using the switches SW1 to SW3. At this time, since the contrast adjustment is not performed frequently, the switches SW1 to SW3 are not specially provided for adjusting the contrast, but the switches used for other purposes are used to reduce waste, and the operation panel is omitted. It is designed to reduce the size.

 FIG. 2 shows the appearance of the operation panel.

For example, there are four arrow keys on the operation panel as shown, which are switches used to move a cursor displayed on a flat display.
Since the operation by this switch does not output a signal to the outside and does not affect many people, three of them are also used for contrast adjustment in this embodiment. Here, in order to distinguish whether these switches are used for moving the cursor or these switches are used for contrast adjustment, for example, switch SW1 is used as a contrast adjustment operation switch, and switch SW1 is pressed down. Switch SW while
2. Make SW3 work as a contrast adjustment switch. The switch SW1 checks the signal level, that is, whether the signal line S4 is "L" or "H", and the switches SW2, SW3 check the signal change, that is, the rising or falling of the signals S5, S6.

Now, when the switches SW2 and SW3 are pressed down, that is, the signals S5 and S6
The following describes the contrast adjustment processing shown in FIG. 3 with the switch SW2 acting as a switch for increasing the contrast and the switch SW3 acting for decreasing the contrast.

Before entering the contrast adjustment processing, first, the signal S4 is set to “L”.
It is checked whether or not the state has continued for 3 seconds or more (see reference). If the state has continued for 3 seconds or more, the contrast adjustment processing is started. This is to prevent the state of the contrast adjustment processing from being accidentally entered while the cursor is being moved.

Then, when the contrast adjustment processing is started, first, the contrast adjustment flag is set to “0” (see), and then the signal S5 is set.
To see if it falls (see). If the signal S5 falls, it is checked whether the signal S4 is "L" (see). If the signal S4 is "H", the contrast adjustment operation is not underway, so that the contrast adjustment flag is kept at "0" and the process proceeds to the contrast change processing (see). If the signal S4 is "L", it means that the contrast adjustment is being performed.
The contrast adjustment flag is set to "1" (indicating the direction of increasing the contrast; see), and the process proceeds to the contrast changing process (see). If signal S5 is not falling, signal S6
Is falling, that is, whether the switch SW3 is pressed down (see). If the signal S6 falls, it is checked whether the signal S4 is "L" (see). signal
If S4 is "H", since the contrast adjustment operation is not underway, the process proceeds to the contrast changing process with the contrast adjustment flag being "0" (see). If the signal S4 is "L", since the contrast adjustment operation is being performed, the contrast adjustment flag is set to "2" (indicating the direction of decreasing the contrast) (see), and the process proceeds to the contrast changing process (see).

Next, the contrast changing process will be described with reference to FIG.

Here, the contrast is changed according to the value of the contrast adjustment flag. For example, if the contrast adjustment flag is “1”, a process to increase the contrast is performed,
If “2”, perform processing to lower contrast and “0”
If so, the contrast is not changed.

First, it is checked whether the contrast adjustment flag is “0” (see). If it is “0”, the contrast change processing is terminated as it is. If not "0", the current contrast value is read from the data memory (see reference numeral 9 in FIG. 6) (
reference). Since the contrast is switched in eight steps here, it is assumed that the contrast value is one of 0 to 7. It is assumed that lower 3 bits of 8-bit data of 1 byte are used as a contrast value. Next, it is checked whether the contrast adjustment flag is "1" (see).

If the contrast adjustment flag is "1", the contrast is increased. However, if the contrast is already the highest, that is, if the contrast value is "0" (see), the contrast cannot be further increased. Therefore, the contrast changing process is terminated as it is.
If the contrast value is not "0", the contrast value is decremented (refer to), and the contrast value is changed to the signal lines S1 to S3.
Output to (see). Regarding the correspondence between the contrast value represented by 3 bits and the signal lines S1 to S3, the 0th bit (least significant bit) is output to S3, the 1st bit is output to S2, and the 2nd bit is output to S1. Therefore, if the contrast value decreases by one, the contrast increases by one step due to the voltage drop due to the following resistance value relationship: R1 + R2 + R3> R1 + R2> R1 + R3>R1> R2 + R3>R2>R3> 0 Although the relationship with the contrast value is reversed, it is needless to say that the present invention is not limited to this. Next, when the contrast value is output to the signal lines S1 to S3, the contrast value is stored in the data memory (see), the contrast adjustment flag is set to "0" (see), and the contrast change processing is ended.

On the other hand, if the contrast adjustment flag is not "1", a process of lowering the contrast is performed. When the contrast is in the lowest state, that is, when the contrast value is “7” (see), the contrast cannot be further reduced, and the contrast changing process is terminated as it is. If the contrast value is not "7", the contrast value is incremented (see), and the contrast value is output to the signal lines S1 to S3 to lower the contrast by one step (see), and the contrast value is stored in the data memory (see FIG. ), Set the contrast adjustment flag to “0” (
), And ends the contrast change processing.

〔The invention's effect〕

According to the present invention, the contrast of the flat display on the operation panel is adjusted via the processing device including the microcomputer, and the signal for adjusting the contrast is digitally given by the transparent switch or the sheet-like operation switch. In addition, problems such as water resistance, oil resistance, and dust resistance of the operation panel surface can be solved. In addition, since the switch used for other purposes, which is arranged on the operation panel as a switch for contrast adjustment, is also used, there is no need to provide a special switch for contrast adjustment, and the operation panel is small. This provides the following advantages.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is an external view of an operation panel, FIG. 3 is a flowchart for explaining a contrast adjusting operation according to the present invention, and FIG. FIG. 5 is a flowchart for explaining the operation, FIG. 5 is a block diagram for explaining the relationship between the operation panel and an external device, and FIG. 6 is a system configuration diagram showing the operation panel. Description of symbols 1 ... operation panel, 2 ... external control device (sequencer), 3 ... mechanical device, 4 ... interface bus, 5
... control cable, 6 ... microcomputer system (CPU),
7 ... Character generator (CG), 8 ... Screen memory, 9 ... Data memory (RAM), 10 ... Internal bus, 11
… Transparent touch key, 11a… Transparent switch (operation switch), 11b… Display panel, 12… Key encoder, 1
3 Display control switch, 14 Loader, 15 Printer, 16 Photocoupler, R1 to R9, Resistance, SW1 to SW3
... switches, S1 to S7 ... signals or signal lines.

Continuation of front page (56) References JP-A-62-106439 (JP, A) JP-A-63-188120 (JP, A) JP-A-60-217393 (JP, A) JP-A-63-192087 (JP) JP-A-63-228317 (JP, A) JP-A-59-101695 (JP, A) JP-A-62-259132 (JP, A) JP-A-62-23068 (JP, A) 3-110982 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) G09G 5/10

Claims (2)

(57) [Claims] An operation panel is connected to an external control device via an interface bus or an input / output interface, and an operation panel surface is composed of a flat display and a transparent switch or a sheet-like operation switch equivalent thereto.
In an operation panel controlled by a computer, a plurality of sets of a contrast adjustment circuit including a combination of a photocoupler and a resistor connected in parallel with the photocoupler are provided between the computer and the flat display; Of the contrast adjustment circuit, a signal for designating a combination of contrast adjustment circuits to be operated is output from the computer, so that a voltage value to be input to the flat display is switched in a plurality of stages to adjust the contrast. By giving instruction information for contrast adjustment from the transparent switch or the sheet-like operation switch to the computer, the computer specifies a combination of a contrast adjustment circuit to be operated corresponding to the instruction information to the adjustment means. Contrast adjusting circuit of the operation panel, characterized in that the contrast adjusted by outputting that signal. 2. A transparent switch or a sheet-like operation switch used for adjusting the contrast is used for another purpose at the time of adjusting the contrast so as to double as a switch used for another purpose. 2. A contrast adjusting circuit for an operation panel according to claim 1, further comprising processing determining means for judging whether or not there is a signal for the purpose of adjusting the contrast, and making it usable for the purpose of adjusting the contrast.