JP4219252B2 - Adapter for detection switch connection - Google Patents

Description

  The present invention relates to a detection switch connection adapter used when connecting a plurality of detection switches that perform on / off operations, and is used, for example, for connection of detection switches for piston positions of a plurality of fluid pressure cylinders.

  Conventionally, a detection switch is attached to a fluid pressure cylinder in order to detect its piston position.

  Usually, each detection switch is individually connected to an input terminal such as a programmable controller, but a plurality of detection switches are often connected to one input terminal. For example, in a clamp fixing device installed in a welding line of an automobile, a plurality of fluid pressure cylinders with detection switches that perform the same operation are installed. In order to detect that all the pistons of these fluid pressure cylinders have reached a predetermined set position, the respective detection switches are used in series with each other.

  However, in that case, if any one of the plurality of detection switches connected in series is off, the whole is turned off, so when the load does not operate, which detection switch is off, or where I don't know the cause of the disconnection.

  In addition, when a plurality of detection switches are connected in parallel to each other, if at least one detection switch is on, the detection switch is turned on as a whole. The cause of whether it is on or somewhere is short-circuited is unknown.

  In those cases, it takes a lot of time and effort to identify a faulty detection switch or faulty location.

  In order to solve such a problem, a three-wire connection adapter disclosed in JP-A-10-321074 is used.

  This conventional adapter for connection includes an input terminal for capturing an ON / OFF signal of the detection switch, an indicator lamp that lights or goes off according to the ON / OFF operation of the detection switch connected to the input terminal, and turns on or off the indicator lamp. Accordingly, a plurality of detection circuit blocks including photocouplers that perform on / off operations are provided. Outputs of the plurality of photocouplers are input to the base of the transistor via an AND circuit or an OR circuit to control the transistor. The output of the transistor is drawn to the outside as an open collector output and drives a load.

  Such a connection adapter has three connection terminals: a connection terminal for an open collector output, a terminal for supplying power (a positive terminal of the power supply), and a ground terminal (a negative terminal of the power supply), A programmable controller or the like is connected by three electric wires.

In the conventional three-wire connection adapter described above, there is a problem that three wires must be wired to the place where the adapter is installed. In general, 2-wire wiring is performed at the machine process site, and in order to use the above-described 3-wire connection adapter, a power supply is separately provided in the vicinity or for power supply. It was necessary to wire extra wires.
Japanese Patent Laid-Open No. 10-321074

  The present invention has been made in view of the above-described problems, and provides a two-wire connection adapter that can be used without separately providing a power source and without separately wiring a power source line. With the goal.

The detection switch connection adapter according to the present invention is a detection switch connection adapter used when connecting a plurality of two-wire detection switches that perform an on / off operation, in which an external load and a power source are connected in series. Two external connection terminals for connecting to each other, a plurality of input terminals for taking on / off signals of the respective detection switches, and a voltage applied to the two external connection terminals, And a plurality of transistors whose outputs are turned on and off by controlling the voltage or current applied to the gate in accordance with the on / off operation of the detection switch, the outputs of which are connected in parallel to each other. or connected in series to each other, which is connected so as to be output to two external connection terminals, before each The transistor is connected so that a voltage or a current supplied from one of the two external connection terminals is applied to each gate through an element connected to each of the two external connection terminals. Are connected such that when it is turned on, the current flowing through each of the elements is bypassed and no voltage is applied to the gate, or no current flows .

Preferably, each of said elements comprises a constant current element and indicator.

  The plurality of transistors have their outputs connected in parallel to each other, and a light emitting diode is connected in series between the parallel connection body and one of the two external connection terminals. Also, a rectifier circuit using a diode bridge is provided between the outputs of the plurality of transistors and the two external connection terminals.

  Another detection switch connection adapter according to the present invention is a detection switch connection adapter used when connecting a plurality of two-wire detection switches that perform an on / off operation, and includes an external load and a power supply. Two external connection terminals for connecting in series, a plurality of input terminals for taking on / off signals of the respective detection switches, and a rectifier circuit by a diode bridge in which an AC side is connected to the two external connection terminals; A plurality of transistors connected in parallel to each other on the DC side of the rectifier circuit, and connected in series between the gates and the drains of the plurality of transistors, respectively. A constant current element and an indicator lamp, each of the detection switches via the input terminal. Made is configured to be connected between each gate and source of each of Njisuta.

  The transistor in the present invention includes various transistors such as a MOS field effect transistor, a junction field effect transistor, and a bipolar transistor. If the transistor is not a field effect transistor but an NPN transistor, for example, the gate may be read as the base, the drain as the collector, and the source as the emitter.

  The constant current circuit includes various configurations. For example, a constant current diode or a circuit that combines a diode or a transistor to obtain a constant current is included.

  According to the present invention, it is possible to provide a two-wire connection adapter that can be used without separately providing a power source and without separately wiring a power source line.

  FIG. 1 is a circuit diagram showing a circuit configuration of a connection adapter 1 for series connection according to an embodiment of the present invention.

  As shown in FIG. 1, the connection adapter 1 includes four constant current diodes RD11-14, five light emitting diodes LD11-15, four N-type MOS field effect transistors TR11-14, and a rectifier circuit R1. 4 sets of input terminals 11a-14a, 11b-14b, and 1 set of output terminals 15 and 16 are comprised.

  The output terminals 15 and 16 are terminals for connecting the external load L1 and the power source P1 in series. The input terminals 11a to 14a and 11b to 14b are terminals for taking on / off signals of the four detection switches S11 to S14, respectively. The rectifier circuit R1 is a diode bridge in which the AC side is connected to the two output terminals 15 and 16.

  The transistors TR11 to 14 are connected so that the drain and the source are parallel to the DC side of the rectifier circuit R1. A light emitting diode LD15 is connected in series to the drains of the transistors TR11-14.

  The constant current diodes RD11 to RD and the light emitting diodes LD11 to LD14 are connected to each other in series, and are connected between the gates and the drains of the transistors TR11 to TR14. The constant current diodes RD11 to 14 have a rated current of several mA to several mA, for example, about 0.5 mA. When the detection switch is turned on, a current corresponding to the rated current flows through the light emitting diodes LD11 to LD14 to emit light.

  The detection switch is connected between the respective gates and the respective sources of the plurality of transistors TR11 to 14 via the input terminals described above.

  The transistors TR11 to 14 are operated by voltages applied to the output terminals 15 and 16, and the voltages applied to the gates are controlled according to the on / off operations of the respective detection switches, and the outputs are turned on / off. Since the outputs of these transistors TR11 to 14 are connected in parallel, when any one of them is turned on, the output terminals 15 and 16 are turned on and the load L1 is operated.

  These circuits constitute the connection adapter 1 by being mounted inside or on the surface of a metal or synthetic resin housing.

  Next, the operation of the connection adapter 1 will be described.

  When the detection switches S11-14 are off, a voltage close to the power supply voltage is applied to the gates of the transistors TR11-14, and the outputs of the transistors TR11-14 are turned on. When the detection switches S11 to 14 are on, the voltage applied to the gates of the transistors TR11 to 14 is short-circuited thereby, the gate voltage becomes zero, and the outputs of the transistors TR11 to 14 are turned off. .

  Therefore, when any one of the detection switches S11 to 14 is off, the output of at least one transistor TR11 to 14 is turned on, so that the output terminals 15 and 16 are turned on. At that time, the circuit CR1 is formed, the load L1 is activated by the current from the power source P1, and the light emitting diode LD15 is lit.

  Only when all the detection switches S11 to S14 are turned on, the outputs of all the transistors TR11 to TR14 are turned off, and the output terminals 15 and 16 are turned off. At this time, the load L1 stops operating, and the light emitting diode LD15 is turned off. Since the light emitting diodes LD11 to 14 are turned on in response to the detection switches S11 to 14 being on, all the light emitting diodes LD11 to 14 are turned on when all the detection switches S11 to 14 are on.

  That is, the connection adapter 1 of the present embodiment operates as a NAND circuit with respect to the inputs of the detection switches S11 to S14. A negative logic circuit such as a NAND circuit can detect not only the operation of each of the detection switches S11 to 14 but also the disconnection of the wiring by the light emitting diodes LD11 to LD14. A limit switch used for detecting an operating end of a mechanical device or the like normally uses a contact configuration as a B contact. The connection adapter 1 constituting the NAND circuit is suitable for connecting a large number of detection switches used for such purposes.

  However, the connection adapter 1 may be configured to perform an operation based on other logic such as an AND circuit operation or an OR circuit operation instead of the NAND circuit operation. Therefore, for example, an inverting circuit or a NOT circuit may be inserted into the outputs of the transistors TR11 to TR14. Further, the outputs of the transistors TR11 to 14 may be connected in series with each other.

  In the connection adapter 1 of the embodiment described above, if the rated current of the constant current diodes RD11-14 is 0.5 mA, the leakage current from the connection adapter 1 is 2 mA even when all the detection switches S11-14 are on. It is extremely small. Therefore, the possibility that the load operates due to such a leakage current is extremely small. However, when it is desired to further reduce the leakage current in order to use a small load, for example, the constant current diodes RD11 to RD11 to 14 having a smaller rated current (for example, about 0.1 mA) are used and operated in accordance with the rated current. The light emitting diodes LD11 to 14 having a small current may be used or the light emitting diodes LD11 to 14 may be omitted.

  According to the connection adapter 1 of the embodiment described above, since it is a two-wire type, it can be used without separately providing a power source or wiring a power source line. The operating state of the detection switches S11 to S14 can be easily confirmed by turning on or off the light emitting diodes LD11 to LD14. Further, even if any of the detection switches fails, the failed detection switch can be identified in a short time. Since the current flowing through the detection switches S11 to S14 is small, the life of the detection switch is extended. Since the number of parts is small and the circuit is simple, the cost can be reduced.

  In the embodiment described above, the number of detection switches that can be connected is four, but may be three or less or five or more. Although the rectifier circuit R1 is provided, the rectifier circuit can be dispensed with when the load is operated by a DC power source. As the transistors TR11 to 14, it is possible to use various transistors other than the field effect transistors, for example, bipolar transistors.

  In addition, the configuration, shape, dimensions, and circuit configuration of the whole or one part of the connection adapter 1 can be appropriately changed in accordance with the spirit of the present invention.

  It is used for confirming the operation of multiple hydraulic cylinders in clamp fixing devices installed in automobile welding lines.

It is a circuit diagram which shows the circuit structure of the connection adapter which concerns on embodiment of this invention.

Explanation of symbols

1 connection adapters 11a to 14a, 11b to 14b input terminals 15 and 16 output terminals (external connection terminals)
TR11-14 Transistors RD11-14 Constant current diode (constant current element)
LD11-14 Light emitting diode R1 Rectifier circuit S11-14 Detection switch

Claims (5)

An adapter for connecting a detection switch used when connecting a plurality of two-wire detection switches that perform on / off operation,
Two external connection terminals for connecting an external load and a power supply in series;
A plurality of input terminals for capturing on / off signals of the respective detection switches;
A plurality of transistors that operate according to voltages applied to the two external connection terminals, and that control the voltage or current applied to the gate in accordance with the on / off operation of each of the detection switches, and the output is turned on / off; Have
The plurality of transistors are connected so that respective outputs are connected in parallel to each other or in series with each other, and output to the two external connection terminals ,
Each of the transistors is connected so that a voltage or a current supplied from one of the two external connection terminals is applied to the gate through an element connected to each of the transistors,
Each of the detection switches is connected to bypass a current flowing through each of the elements when it is turned on so that no voltage is applied to the gate or no current flows .
An adapter for connecting a detection switch. Each of the elements includes a constant current device and a display lamp,
The adapter for detecting a switch according to claim 1. Each of the plurality of transistors is connected in parallel with each other, and a light emitting diode is connected in series between the parallel connection body and one of the two external connection terminals.
An adapter for connecting the detection switch according to claim 1 or 2. A rectifier circuit using a diode bridge is provided between the outputs of the plurality of transistors and the two external connection terminals.
The adapter for connecting a detection switch according to any one of claims 1 to 3. An adapter for connecting a detection switch used when connecting a plurality of two-wire detection switches that perform on / off operation,
Two external connection terminals for connecting an external load and a power supply in series;
A plurality of input terminals for capturing on / off signals of the respective detection switches;
A rectifier circuit with a diode bridge in which the AC side is connected to the two external connection terminals;
A plurality of transistors connected so that drains and sources are parallel to each other with respect to the DC side of the rectifier circuit;
A constant current element and an indicator lamp connected in series between each gate and each drain of the plurality of transistors,
Each of the detection switches is configured to be connected between each gate and each source of the plurality of transistors via the input terminal.
An adapter for connecting a detection switch.

Images