JPH02284518A - Input interface circuit - Google Patents

Abstract

PURPOSE:To share a non-voltage contact point and voltage contact point interface by connecting a diode in series to an input and connecting a transistor where a base, an emitter and a collector are respectively connected between input lines. CONSTITUTION:A contact point interface equipment 1 executes interface at a non-voltage contact point or a voltage contact point. At the time of non- voltage contact point interface, a current flows from an interface power source 4 to the contact point interface equipment 1, and a photocoupler 5 is turned on. At the time of voltage contact point interface on the other hand, the voltage of the voltage contact point is impressed on the base-side of a switching transistor 3 through a resistor R1. When the rate of bias resistors R3 and R4 is appropriately selected, the transistor 3 is turned on irrespective of the voltage of the voltage contact point. Since the photocoupler 5 is turned on, interface is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a connection system between devices, and particularly to an input interface circuit in which the interface is performed using contacts.

(Prior Art) Conventionally, as this type of input interface, a non-voltage contact interface as shown in FIG. 2 or a voltage contact interface as shown in FIG. 8 has been adopted.

In FIG. 2, 7 is a non-voltage contact interface device, 8 is an interface power supply, 9 is a photocoupler, and 10
is a logic section, and R6 is a resistor.

In Figure 8, 11 is a voltage contact interface device, 12! d power supply, 13 is a photocoupler, 14 is a logic section,
R7 is a resistor.

These interfaces did not allow common input interface circuits. Furthermore, in the voltage contact interface 11 shown in FIG. 3, it was necessary to change the resistor R6 (depending on the voltage of the power supply 12), and even the input interface circuit could not be shared.

(Problems to be Solved by the Invention) In the conventional input interface circuits described above, the input interface circuits are different between the non-voltage contact interface and the voltage-contact interface.
In the voltage contact interface shown in the figure, power supply 1
There is a drawback that the resistor R8 is different depending on the voltage of the input interface 2, and the input interface circuit cannot be shared. Therefore,
There is a drawback that it is necessary to prepare a variety of input interface circuits depending on the type of contact and the voltage value. .

An object of the present invention is to solve the above-mentioned drawbacks of the conventional interface by connecting a diode in series with the input and connecting a transistor whose base, emitter, and collector are each connected via a resistor between the input lines. An object of the present invention is to provide an interface circuit configured to be shared.

(Means for Solving the Problems) An input interface circuit according to the present invention includes a transistor and a diode.

The transistor capacitor, emitter, and collector are each connected between the contact input lines via a resistor.

The diode is connected between the collector and the base of the transistor in series with the base through the base resistor in the forward direction, with the base resistor side being the input side.

(Example) Next, one aspect of the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of an interface circuit according to the present invention.

In FIG. 1, 1 is a contact interface device, 2 is a diode, 3 is a transistor, 4 is an interface power supply, 5 is a photocoupler, 6 is a logic section, and R1 to R5 are resistors, respectively.

In FIG. 1, a contact interface device 1 is a device that performs an interface using a non-voltage contact or a dynamic voltage contact.

In the case of a voltage-free contact interface, current flows from the interface power supply 4 to the contact interface device 1 via the current limiting resistor R5, the interface photocoupler 5, and the backflow prevention diode 2, turning on the photocoupler 5. Become.

On the other hand, in the case of a voltage contact interface, the voltage of the voltage contact is applied to the base side of the switching transistor 3 via the resistor R1, and the ratio of the bias resistors R3 and R4 is appropriately selected. For example, the transistor 3 can be turned on regardless of the voltage of the voltage contact.

At this time, from the interface power supply 4 to the current limiting resistor R5 and the interface photocoupler 5,
, a current flows through the current limiting resistor iR2, the switching transistor 3, and the biasing resistor R3, and the photocoupler 5 is turned on, so that an interface is possible.

(Effects of the Invention) As explained above, the present invention connects a diode in series with the input and connects the base, emitter,
Also, by connecting transistors whose collectors are connected via resistors, the non-voltage contact interface and the voltage contact interface can both be used as a common interface.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of an input interface circuit according to the present invention. FIG. 2 is a block diagram illustrating a series of prior art non-voltage contact interface circuits. FIG. 8 is a block diagram showing an example of a voltage contact interface circuit according to the prior art. 1. Contact interface device 2. Diode 3. Warm transistor 4.8, 12. Power supply 5.! 1.15... Photocoupler 8.10, 14... Logic section 7-... Voltageless contact interface device 1111...
Voltage contact interface equipment R1~R7 resistance resistor

Claims (1)

[Claims] The base, emitter, and collector are each
A transistor connected to be turned on between the contact input lines via an eighth resistor, and a transistor connected in series with the base via the second resistor between the collector and base of the transistor. An input interface circuit comprising: a diode connected in such a direction that the second resistor side becomes the input side.