JPS6255249B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a switch selection display circuit, and particularly to a switch selection display circuit that generates a code and displays _a lamp when one of n different pushbutton switches is selected and pressed. Regarding circuits.

The operator console of a telemeter device or telecontrol device is equipped with n pushbutton switches, and when any one of these n pushbutton switches is pressed, the corresponding switch is activated. The corresponding signal is encoded and output, and a lamp is lit to indicate that the switch has been selected.

Conventionally, devices equipped with this type of pushbutton switch often employ a pushbutton switch that is mechanically configured with a spring, or a pushbutton switch that is held down by a permanent magnet such as a latching relay, or a pushbutton switch that is held down by a permanent magnet such as a latching relay. In some cases, there was little relationship between the drive circuit and the coded signal generation circuit, which is composed of, for example, a diode matrix.
By the way, when the number of push button switches to be configured is small, it is relatively easy to arrange and configure them.
As the number increases, the installation space and internal wiring become complicated.

Therefore, the main object of the present invention is to provide a switch which has an extremely simple internal electrical connection configuration and is easily expandable even when a large number of switches are installed.
The purpose of the present invention is to provide a nC ₁ selection display circuit.

To summarize the invention, there are n switches, a flip-flop serves as a state storage means for remembering that any one of the switches has been selectively pressed, and the flip-flop is incremented based on the output of the flip-flop and a clock pulse. In a switch selection circuit equipped with a counter, a decoder that decodes the counter output to derive individual outputs, and an indicator lamp provided corresponding to the decoder output, the counter steps only when one of n switches is selectively pressed. This is an _nC1 selection display circuit for a switch that stops the counter, uses this counter output as a coded signal for the switch, and decodes this signal to light the corresponding lamp.

The above objects and other objects and features of the invention will become more apparent from the following detailed description with reference to the drawings.

The figure shows one embodiment of this invention, in which the switch is 4
In this case, _the circuit diagram for _4C1 selection is shown. In the configuration, PBS0, PBS1, PBS2, and PBS3 are single-circuit pushbutton switches that automatically return.
One of the contacts of these switches PBS0 to PBS4 is
They are commonly connected to the K input of the JK flip-flop 1, which serves as state storage means for storing which one has been selected. The pushbutton switch RBS is
It is used to release the memory state of the JK flip-flop 1, and one contact of this switch RBS is connected to the J input of the JK flip-flop 1. The Q output of the JK flip-flop 1 is 2
It is applied to one input of the input NAND gate 2, and is also applied to the input side of the relay driver RD that energizes the relay R. Also, the output is 2 inputs
It is given as one input of NOR gate 3. As shown, .phi.1 and .phi.2 are clock pulses generated by a pulse generator (not shown) and supplied to the circuit shown. The phase relationship between the clocks φ1 and φ2 is as shown in the figure.

Now, the clock is given to the input of the JK flip-flop, and the clock φ1 is applied to the two inputs of the JK flip-flop.
Given as the other input of NAND gate 2, φ2
is given as the other input of the two-input NOR gate 3. The output of NAND gate 2 is applied to the input of 2-bit binary counter 4. The ²⁰ output of this counter 4 is given as the ²⁰ input of the 2-bit decoder 5, and the ²¹ output of the counter 4 is given as the ²¹ input of the decoder 5. The decoder 5 derives four different outputs based on these 2-bit inputs 2 ⁰ and 2 ¹ . Then, the output 0 of the decoder 5 passes through the lamp driver LD0 to the push button switch.
Connected to the other contact of PBS0 and lamp
Connected to one end of LP0. Similarly, outputs 1, 2, and 3 of decoder 5 are each lamp driver LD.
1.Push button switch PBS via LD2 and LD3
1, PBS2, and PBS3, and also connected to one end of lamps LP1, LP2, and LP3, respectively. And lamp LP0, LP
The other ends of the relays 1, LP2, and LP3 are commonly connected to one contact of the A contact (normally open contact) r of the relay R. The output of the 2-input NOR gate 3 is the input (chip enable terminal) of the decoder 5.
given to. Note that power +V is the power supplied to relay R and lamps LP0 to LP3,
Diodes D0 to D4 are protection diodes for preventing backflow, and inverters 6 and 7 are simply used to represent logical polarity.

Note that the clocks φ1 and φ2 indicate that the contents of the counter 4 are set at least once during the contact conduction time from when one of the pushbutton switches PBS0, PBS2, and PBS3 is pressed until the pressed state is released. The frequency is set such that it changes to all of ``0'', ``1'', ``2'', and ``3''.

In operation, as an initial state, flip-flop 1 is in the set state and its Q output is "H".
(high level) and the content of the counter 4 is "0". Therefore, the "H" signal is applied to the input of the decoder 5, and the decoder 5 is disabled. Now, since the Q output of flip-flop 1 is "H", NAND gate 2 is activated, and when clock φ1 is input, NAND gate 2 passes this clock φ1, inverts the phase, and outputs it. . Then, a pulse of negative polarity is applied to the counter 4.
advances. Then, its content becomes "1".
Next, when the clock φ2 is input to the NOR gate 3, the output of the NOR gate 3 becomes "L" (low level), and this signal is applied to the input of the decoder 5, thereby activating the decoder 5. In response, this decoder 5 outputs an "L" signal to one output corresponding to the content "1" of the counter 4 (the other outputs 0, 2, and 3 are all "H"). If pushbutton switch PBS1 is not pressed at this time, lamp driver LD1 is energized but relay R is not energized, so contact r
remains OFF and +V power is not supplied to lamp LP1. When the next clock φ1 is input, the contents of the counter 4 become "2" and only the two outputs of the decoder 5 become "L" in exactly the same way as described above. At this time, if the pushbutton switch PBS2 is not pressed, the counter 4 further increments at the next clock φ1. In other words, the pushbutton switch PBS0~
When none of the PBSs 3 are pressed, the above-described operations are repeated cyclically.

Now, it is assumed here that the push button switch PBS2 is pressed just before the second output of the decoder 5 becomes "L". At this time, the lamp driver LD2 is energized and the output becomes "L", which is input to the inverter 7 via the push button switch PBS2, and the output is "L".
Apply "H" to the K input of flip-flop 1.
Since the clock is applied to the input at a higher frequency than clocks φ1 and φ2, the JK flip-flop 1 is inverted when the negative pulse of the clock is input, and the Q output becomes "L" and the output becomes "H". . In response, relay driver RD is energized to excite relay R and turn on contact r. At the same time, the NAND gate 2 is disabled and the input of the clock φ1 is disabled. Then, the input of the counter 4 becomes always "H" and the step stops.
In addition, the input of the decoder 5 is always “L”,
The two outputs of the decoder 5 each remain at "L". Therefore, the moment contact r of relay R turns ON, power +V is supplied to lamp LP2, lamp LP2 lights up, and this state continues. At this time, since the counter 4 remains fixed at its content "2", this output signal is supplied as a code signal to another input device (not shown). In addition, in this state, the pushbutton switch PBS0, PBS
1. It is obvious that even if PBS3 is pressed, the corresponding lamp will not light up.

Next, if you want to release this state, switch
Press RBS and give "H" to the J input of flip-flop 1. When a negative pulse of the input clock is applied, the flip-flop 1 is inverted and its Q output becomes "H" and its output becomes "L". Therefore, the clock φ1 to the counter 4 is enabled and the holding state is released. Then, by clock φ1, "3" → "0" → "1" →
Repeat cyclically like "2" → "3",
The search continues to see if any one of the pushbutton switches has been pressed.

For example, if the pushbutton switch PBS2 is pressed just before the output of the decoder 5 becomes "L", the output of the decoder 5 becomes "L" when the clock φ2 becomes "H"; Since the contact of button switch PBS0 is open, this output is not transmitted to the K input of JK flip-flop 1. At this time, since the contact of the pushbutton switch PBS2 is closed, the two outputs of the decoder 5 "H" are changed to "L" by the inverter 7 and are applied to the K input of the JK flip-flop 1. Therefore, the Q output and the output of the JK flip-flop 1 are not inverted, and the counter 4 is incremented by the clock φ1. Then, when the two outputs of the decoder 5 become "L", this output is transferred to the inverter 7.
is set to "H" and applied to the K input of JK flip-flop 1, and the Q of JK flip-flop 1 is set to "H".
The output is inverted to "L" and the output is inverted to "H".
As a result, the input of the counter 4 becomes always "H" and the step stops.

In this way, the push button switch is activated immediately before any of the three outputs from the decoder 5 becomes "L".
Even if PBS2 is pressed (even if PBS2 is pressed), the increment of counter 4 is stopped when output 2 becomes "L", and thereby the contents of counter 4 are fixed at "2". At the same time, the lamp LP2
lights up.

As described above, when one of the four pushbutton switches is selected and pressed, a lamp indicating the coded output and the selection of the code can be lit.

In the above-described embodiment, the disabling and enabling of the decoder 5 is controlled by the clock pulse φ2 or the output of the JK flip-flop 1. However, even if the input of the decoder 5 is always fixed at "L" and kept in the active state, the operation intended by this embodiment can be accomplished. However, counter 4
It is necessary to set the speed of the clock .phi.1 so that "H" is applied to the K terminal of the flip-flop 1 after the decoded output from the decoder 5 becomes sufficiently stable after the clock .phi.1 is incremented by the clock .phi.1.

Further, in this embodiment, only 2-bit encoding and display have been described, but it goes without saying that n-bit encoding is also possible if the number of bits of the counter and decoder is expanded. Furthermore, if redundancy is provided in the configuration of this circuit at the beginning, it can be easily expanded through extremely simple connections.

Furthermore, in this embodiment, a one-circuit automatic reset pushbutton switch was used, but the figure shows a switch having two circuits of contacts, with all the contacts of the second circuit connected in parallel, for example, through a differential circuit. Connect to connection point P on the left side of the selection cancellation switch RBS. In this way, simply by pressing the next switch, the state of the previous switch can be canceled and selection can also be made using this switch. Although the switch RBS is not particularly necessary at this time, it is used to turn off the lamp when it is no longer necessary to turn on the lamp.

As described above, in this invention, the code signal can be generated extremely easily, and the lamp display circuit can also be created with an extremely simple connection configuration.
This has the advantage that internal wiring etc. are also simplified. It also has the advantage of being easily expandable even if n becomes large.

[Brief explanation of the drawing]

The figure shows a push button switch according to an embodiment of the present invention.
_4C1 selection circuit _is shown. In the figure, PBS0 to PBS3 are one-circuit automatic return pushbutton switches, LP0 to LP3 are lamps, 1 is a JK flip-flop, 4 is a counter, 5 is a decoder, R is a relay, and RBS is a pushbutton switch for turning off the light.

Claims (1)

[Scope of Claims] 1. A counter that is stepped based on a clock pulse and repeatedly outputs n coded signals in order; and a decoder that receives the output of the counter and derives n individual outputs according to the contents thereof. , n switches having one contact connected to an individual output terminal of the decoder and the other contact being commonly connected; and a state storage means for receiving an output from a common connection point of the switches and storing the output state. , n indicator lamps that are provided corresponding to the n switches and turn on when the corresponding switches are turned on based on the output of the state storage means and the individual output of the decoder; A switch selection display circuit comprising means for receiving an output from a storage means and stopping the progress of the counter when the output state indicates that any one of the n switches is turned on. 2. The switch selection display circuit according to claim 1, further comprising a release means for releasing the stored state of the state storage means. 3. The switch selection display circuit according to claim 2, wherein the release means is a switch. 4. The switch selection display circuit according to claim 2 or 3, wherein each of the n switches is configured as a two-circuit switch, and the canceling means includes one circuit of the n switches.