JPS61245420A - Inter-contact stop detection circuit for brush - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] Output of the lowest value of a binary value indicating which contact number the rotary switch's plaque has selected and the NAND of all even-numbered contacts of the rotary switch. By taking the logical product with , the circuit for detecting open/stopped contacts of the plaque is made into a small-scale circuit configuration.

[Industrial application field]

The present invention relates to an improvement in a brush contact open/stop detection circuit for detecting that a brush of a rotary switch used in electronic equipment 1, communication equipment, etc. has stopped between the contacts.

In a rotary switch, a problem occurs in which the brush stops between the contacts, but in this case the inside of the rotary switch cannot be seen immediately, so it is necessary to make this visible from the outside.

In this case, it is desirable to be able to detect with a small-scale circuit configuration.

[Conventional technology]

FIG. 2 is a circuit diagram of a conventional brush contact stop detection circuit.

In the figure, 1 to 9 are rotary switch contact numbers, and 10 is 1
Zero-to-binary conversion circuit, 11 to 19. 29 to 33 are NAND circuits, 20 to 28 are NOT circuits, 34 is OR circuit, ■ is pull-up voltage, 40 to 43 are each 2° + 2' + 2" + 2
3 shows the output terminal of the digital value.

Although FIG. 2 shows a case where there are nine contacts, this number is not limited.

In Figure 2, 10 from the contact point of the rotary switch.
Among the lines to the decimal-to-binary conversion circuit 10, those that are not selected by the plug are kept at the level by the pull amplifier voltage, and the selected lines are grounded and set to O level, and the digital value corresponding to the contact number is It is output from the output terminal of the decimal/binary conversion circuit 10.

For example, when the contact number 1 is grounded in black, a rubel is output from the output terminal 40 indicating the digit value 2° of the decimal-to-bin conversion circuit 10, and when the contact number 2 is grounded, Output terminal 4 indicating digital value 2'
Lebel is output from 0.

In this case, if the brush is not stopped between the contacts, the output of the NAND circuits 11-18 is level, so the output of the NAND circuit 19 is 0 level, and the black is, for example, 2
If the motor stops between the contacts No. 3, the output of the NAND circuit 12 becomes O level, and the output of the NAND circuit 19 becomes a level, and it is possible to detect that the motor stops between the contacts.

[Problem that the invention attempts to solve L2] However, in the conventional brush contact open/stop detection circuit, in addition to the decimal-to-binary conversion circuit, 19 NAND circuits and 9 NOT circuits are required even in the example of Fig. 2. There is a problem that the circuit scale becomes large.

[Means for solving problems]

The above problem is caused by the terminal (40) indicating the lowest value of the decimal-to-binary conversion circuit (10) which indicates which contact number the rotary switch plaque has selected in a digital value. The output and the decimal-to-binary conversion circuit (10) for all even-numbered contacts of the rotary switch.
The output of the NAND circuit (35) obtained by logically multiplying the inputs to the AND circuit (36) is input to the AND circuit (36), and this output detects that the black of the rotary switch has stopped between the contacts. This problem is solved by Black's contact open/stop detection circuit.

[Effect]

According to the present invention, the output of the NAND circuit 35, which is the logical product of all even-numbered contacts of the rotary switch, becomes a rubel when the black selects an even-numbered contact and stops between the contacts, while a decimal The output of the output terminal 40 indicating the lowest value of the binary conversion circuit 10 is O level when the brush selects an even-numbered contact, and becomes LUHEL when the brush is stopped between the contacts, so the output of the AND circuit 36 is When the black stops between the contacts, it becomes a rubel, and it can be detected that the black stops between the contacts.

In this case, the circuit scale can be reduced to just one NAND circuit and one AND circuit.

〔Example〕

FIG. 1 is a circuit diagram of a black contact open/stop detection circuit according to an embodiment of the present invention.

In the figure, numeral 35 indicates a NAND circuit, and numeral 36 indicates an AND circuit, and the same reference numerals indicate the same functions throughout the figures.

The difference in FIG. 1 from the case in FIG. 1
The output of the output terminal having the lowest value of 0 is input to the AND circuit 36, and the output of the AND circuit 36 is used to detect that the brush has stopped between the contacts.

That is, the output of the NAND circuit 35, which is the logical product of all even-numbered contacts of the rotary switch, becomes a rubel when Black selects an even-numbered contact or stops between the contacts, while the output from the decimal-to-binary conversion circuit The output of the output terminal 40 indicating the lowest value of 10 is O level when the black selects an even numbered contact, and becomes a level when the black stops between the contacts, so the output of the AND circuit 36 is When the brush stops between the contacts, it becomes a rubel and it can be detected that the brush has stopped between the contacts.

In this case, the black contact open/stop detection circuit can be reduced in size by requiring only one NAND circuit and one AND circuit in addition to the decimal/binary conversion circuit 10, as shown in FIG.

When using the value of the interview point number multiplied by 10 or 100 as a numerical value, consider the even number in the highest digit to be an even number.
The lowest value of the decimal-to-binary conversion circuit.

As the output j terminal, a terminal indicating the lowest value that changes as information may be used.

〔Effect of the invention〕

As explained in detail above, according to the present invention, the circuit scale of the brush contact open/stop detection circuit can be made extremely small.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a brush contact open/stop detection circuit according to an embodiment of the present invention, and FIG. 2 is a circuit diagram of a conventional platter contact open/stop detection circuit. In the figure, 1 to 9 are contact numbers, 10 is a decimal to binary conversion circuit, 11 to 19, 29 to 33.35 are NAND circuits, 20 to 2
8 is a NOT circuit 34 is an OR circuit, 36 is an AND circuit, 40 to 43 are output terminals, and ■ is a pull-up voltage.

Claims (1)

[Claims] An output from a terminal (40) indicating the lowest value of a decimal-to-binary conversion circuit (10) indicating which contact number the brush of a rotary switch has selected as a digital value; 10 of all even numbered contacts of the rotary switch
The output of the NAND circuit (35), which is the logical product of the inputs to the binary conversion circuit (10), is input to the AND circuit (36), and this output causes the brush of the rotary switch to stop between the contacts. A stop detection circuit between brush contacts is characterized in that the circuit detects a stoppage between contacts of a brush.