JP2629488B2 - Multi-output sensor circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit for a sensor having multiple outputs.

[0002]

2. Description of the Related Art FIG. 3 shows a circuit operated by a DC power supply, and an output signal is turned on / off by a transistor open collector method.
FIG. 2 is a conventional basic circuit diagram of outputting a signal at two levels of OFF, in which 1 is a sensor for performing a detection operation and outputting a detection signal, Vcc is a (+) side input terminal of a DC power supply,
Out is the output signal terminal, GND is the power supply and signal (-).
A side terminal, TR1, is an output transistor for externally outputting a detection signal from the sensor 1.

Next, the operation will be described. When a DC power supply is connected between the (+) side input terminal Vcc and the (-) side terminal GND of the DC power supply, the sensor 1 starts operating. When a detection target is detected, a base signal is supplied to the transistor TR1 and the transistor TR1 is turned on. Turn on. In an external input circuit that receives an output signal from the sensor circuit as an input, when a load having a (+) potential is connected to the output signal terminal OUT with respect to the (−) terminal GND, the transistor T that is not detecting is connected.
When R1 is off, the output signal terminal Out goes to the voltage level of the load ("H" level). On the other hand, when the transistor TR1 at the time of detection is on, the output signal terminal Out goes to 0V ("L" level).
Level), and detection / non-detection can be obtained by two voltage levels of “L” / “H”.

[0004]

Since the conventional sensor circuit is constructed as described above, as shown in FIG. 4, one sensor 1 is provided with photocouplers PC1 and PC2 and a resistor R1.
1, two input circuits 20, 2 having R12 and R21, R22, respectively, and operating at different DC voltages E1, E2.
When 1 is connected, there is a problem that the sensor 1 becomes inoperable when the power supply E1 on the sensor power supply side becomes 0V. When the power supply E2 becomes 0V, the transistor TR
Even when 1 is off (at the time of non-detection), a current flows through the photocoupler PC1 of the input circuit 20 to the terminal GND via the resistors R22 and R21, and there is a problem that erroneous detection is performed. The present invention has been made to solve the above problems,
It is an object of the present invention to provide another output sensor circuit which can operate even if a plurality of input circuits of one sensor are connected without affecting other input circuits, and can operate if the power supply of one input circuit is normal. I do.

[0005]

The present invention comprises a sensor and a sensor.
First and second DC power supplies for supplying power to the
And power supply circuit for sensor from second DC power supply to sensor
A diode connected to each of the
, A first transistor and a second transistor
Is installed corresponding to the DC power supply of the
First and second DC power supplies to their corresponding first and second DC power supplies.
And a load power supply circuit for supplying power to the second load . Also, only load power supply circuit
It is connected to an iod. In addition, the power supply circuit for the sensor
With a diode connected to both the circuit and the load feed circuit
It is.

[0006]

According to the present invention, connected diodes in the sensor power supply circuit supplies the highest power supply voltage to the sensor in the input circuit is connected. Further, diode being against <br/> connection to a load power supply circuit prevents current sneak between multiple circuits.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is a circuit diagram showing an embodiment of a multi-output sensor circuit according to the present invention, wherein 1 is a sensor for performing a detection operation and outputting a detection signal, and TR1 is for outputting a detection signal from the sensor 1 to the outside. The output transistors DV1 to DVn are a first diode group connected to the (+) side power supply unit of the sensor 1 with a common cathode, and Vcc1 to Vccn are external power supplies connected to the anode side of the diodes DV1 to DVn. Terminals, DO1 to DOn are output transistors T
A second cathode connected in common to the collector of R1
, And Out1 to Outn are diodes DO
1 to DOn are external output terminals connected to the anodes.

Next, the operation when the other output sensor circuit of FIG. 1 is connected to a plurality of input circuits will be described with reference to FIG. First, when the power supplies E1 and E2 are both normal, the higher voltage is selected by the diodes DV1 and DV2 and supplied to the sensor 1. And the transistor T
When R1 is on, E1 (+) → R on the input circuit 20 side.
11 → PC1 → Out1 → DO1 → TR1 → GND → E
1 (−), and E2 (+) on the input circuit 21 side.
→ R21 → PC2 → Out2 → DO2 → TR1 → GND
→ A read current flows through the path E2 (-). When the transistor TR1 is off, the photocouplers PC1,
There is no current flow route through the route via PC2,
No read current flows.

Next, assuming that the voltage of the power supply E1 of the input circuit 20 goes down (0 V), the sensor power is supplied from the power supply E2 of the input circuit 21 via the diode DV2. At this time, the input circuit 20 is blocked by the diode DV1 and there is no power supply. On the other hand, when reading the sensor signal in the input circuit 21, when the transistor TR1 is on, E2 (+) → R21 → PC2 → O
A read current flows through a route of ut2 → TR1 → GND → E2 (−). When the transistor TR1 is off,
E2 (+) → R21 → PC2 → DO2 → DO1 → R12
The current tries to flow in the route of → R11 → E1 → GND → E1 (−), but is prevented by DO1 and is not erroneously detected.

Although the above embodiment has been described with reference to the case of two outputs, the same operation is performed for more than two outputs. In the present invention, connection to a plurality of input circuits is made possible by a circuit inside the sensor. However, the same effect can be obtained by adding a similar circuit externally to a conventional sensor.

[0011]

As described above, according to the present invention, the power supply circuit for the first and second DC power supplies is provided despite the fact that the sensor and the transistor are shared by the power supply and the load.
Is provided with a diode connected in the forward direction , even if a voltage drop trouble occurs in one of the first and second DC power supplies, the other which does not have a trouble malfunctions. Can be used normally without any problem. Also, the first and second DC power
Even if the DC voltage is lost to one of the sources due to power-off, etc., the potential difference between the two poles is lost and the mere conduction state is established, the DC power supply is connected to the load power supply circuit that supplies power to the load from the power source with the reduced potential difference By the action of the diode,
The current of the load power supply circuit on the other power supply side can be blocked, and the on / off state of the sensor can be read normally.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a multi-output sensor circuit of the present invention.

FIG. 2 is a connection circuit diagram of an example in which the multi-output sensor circuit of the present invention is connected to two input circuits.

FIG. 3 is a basic configuration diagram of a conventional sensor circuit.

FIG. 4 is a connection circuit diagram of an example in which a conventional multi-output sensor circuit is connected to two input circuits.

[Explanation of symbols]

 1 Sensor TR1 Transistor DV1 to DVn Diode DO1 to DOn Diode

Claims (3)

(57) [Claims] 1. A sensor and first and second DC power supplies for supplying power to the sensor in parallel.
And a sensor from the first and second DC power supplies to the sensor.
Power supply circuits connected to the
And a transistor that operates according to the output of the sensor, and is provided corresponding to the first and second DC power supplies.
During the operation of the transistor, the first and second DC
Power from a power supply to its corresponding first and second loads
A multi-output sensor circuit including a load power supply circuit. 2. A sensor and first and second DC power supplies for supplying power to the sensor in parallel.
And a transistor that operates according to the output of the sensor, and is disposed corresponding to the first and second DC power supplies.
During the operation of the transistor, the first and second DC
Power from a power supply to its corresponding first and second loads
A load power supply circuit, and the first and second load power supply circuits.
A diode having a diode connected in a forward direction to a DC power supply.
Output sensor circuit. 3. A sensor and first and second DC power supplies for supplying power to the sensor in parallel.
And a sensor from the first and second DC power supplies to the sensor.
First power supply circuit connected to each of the power supply circuits for
An ion, a transistor operated by the output of the sensor, and the first and second direct currents during operation of the transistor.
Power supply from a power supply to its corresponding first and second loads
Load power supply circuit, and the first and second load power supply circuits, respectively.
A second diode connected in a forward direction to the DC power supply.
Multi-output sensor circuit.