JPH0130752Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> This invention particularly relates to a selection display device using a rotary switch or the like.

<Prior Art> There are times when it is desired to output an output to a desired output terminal by switching the contacts of a rotary switch. In this case, as shown in Fig. 1, a double rotary switch RS is used, and each fixed contact 1 to SW ₁ of one switch SW 1 is used.
n to each of the output terminals T ₁ to Tn, and each fixed contact 11 to one of the other switch SW ₂ .
Light emitting diodes _D1 to Dn are connected to _n1 , respectively. Therefore, if the second position is selected as shown, an output is output from the terminal _T2 and the light emitting diode _D2 lights up.

The reason why the configuration as shown is usually used is that the power supply to the switch SW ₂ can be freely selected in accordance with the rating of the light emitting diode, regardless of the power supply to the switch SW ₁ .

<Problems to be solved by the invention> By the way, in this type of rotary switch, poor contact easily occurs between the movable contact and the fixed contact due to contact wear, etc., and when such a poor contact occurs, the designated terminal The disadvantage is that there is a discrepancy between the output and the display.

In other words, the light emitting diode _D2 is lit even though there is no output from the terminal _T2 , or conversely, there is an output from the terminal _T2 even though _D2 is off.

This invention aims to solve these drawbacks of the prior art.

<Means for Solving the Problems> For the above purpose, the present invention provides each fixed contact of a rotary switch having a plurality of switching contacts, and each output terminal provided for taking out the output of those contacts. An OR circuit is provided between each
The outputs of these respective OR circuits are supplied to one output terminal and the other to the input of each buffer gate, and a light emitting diode is connected to the output of each buffer gate.

<Function> According to the above configuration, the contact output of a specific contact of the rotary switch (for example, the second contact as shown in FIG. 2) is output by the OR circuit (for example, O ₂ ) connected to that contact. However, while it is output to a predetermined output terminal (for example, T ₂ ) connected to the output of this OR circuit, it is also supplied to a buffer gate (for example, Q ₂ ) connected to this OR circuit. The output of this buffer gate lights up a light emitting diode (for example, D ₂ ) connected thereto. In other words, if there is an output at the output terminal, the light emitting diode in that circuit will light up, and if there is no output, the light emitting diode will not light up, and the output and display will always match regardless of the contact state of the rotary switch.

By connecting a buffer gate to each light emitting diode, the output level of the OR circuit (usually around 5V DC) is not limited by the forward voltage drop of the light emitting diode (usually around 1.6 to 2V DC). This is due to the fact that a light emitting diode can be connected to the output of the OR circuit.

Of course, an interlocking rotary switch may be used, and contact outputs having the same order may be input as inputs to the OR circuit.

<Example> An example of the present invention is shown in FIG. This figure uses a double rotary switch to improve the contact reliability of the contacts, and configures the contact outputs of the same order as the inputs of the OR circuit. However, the use of a double rotary switch itself is not the gist of this invention.

FIG. 2 will be explained below. Note that the same reference numerals as in FIG. 1 indicate the same parts, so the explanation will be omitted.

O ₁ ~ On are OR circuits that input the contact outputs of the same order between switches SW ₁ and SW ₂ , and Q ₁ ~ Qn are
This is a buffer gate for lighting the light emitting diodes D ₁ -Dn without affecting the output level of the OR circuits O ₁ -On.

Next, to explain the operation of the present invention, if the second position is selected as shown in the figure, an output is output from the OR circuit O ₂ by the output of either the fixed contact 2 or 21, and this is the output terminal T ₂ guided by.

At the same time, the output of the OR circuit _O2 is input to the buffer gate _Q2 , where the light emitting diode _D2
The signal is converted to the most suitable signal for lighting the light emitting diode _D2 . This lighting indicates the selected position. If, for some reason, there is no output from the OR circuit O ₂ (therefore, to the output terminal T ₂ ) even though the rotary switch RS is selected as the second one, the light emitting diode D ₂ will not light up.

In this way, the output status of the output terminal and its display status can always be matched.

<Effects of the invention> The invention is structured so that a light emitting diode is connected to the output of each OR circuit through a buffer gate, so the output status of the output terminal is always monitored without affecting the output of the OR circuit. This makes it possible to match the display states of the selected circuits, which is highly effective in monitoring and managing the selection circuit.

[Brief explanation of drawings]

FIG. 1 is a connection diagram showing a conventional device, and FIG. 2 is a connection diagram showing an embodiment of the present invention. RS……Rotary switch, O ₁ ~On…OR circuit, Q ₁ ~Qn…Buffer gate, D ₁ ~Dn…
...Light emitting diode.

Claims (1)

[Claims for Utility Model Registration] An output terminal for taking out the output of each OR circuit connected to each contact of a rotary switch having a plurality of switching contacts; a respective buffer gate for converting the output; and a respective buffer gate connected to the respective buffer gate;
A selection display device comprising a light emitting diode lit by the output of each of the buffer gates.