JPS62229313A - Control system for application of power supply - Google Patents

Abstract

PURPOSE:To omit an exclusive power supply for drive of a receiving means by using a means which secures a loop-shaped data line and receives the indicating signal for application of power supply from a remote device within said loop before application of the power supply of a terminal equipment. CONSTITUTION:In a center system 20 the transmission data is set at '1' when the power supply of a terminal equipment 30 is applied. Thus a current flows toward a driver 22 from a power supply +Vcc of the system 20 through a loop-shaped data line 3a and a photodiode 31a of a receiving circuit 31 is actuated. As a result, the conduction is secured between the collector and the emitter of a transistor 31b and then between input terminals (a) and (b) of a power unit 33. Then a power supply switch (not shown in a figure) is applied and the power supply is applied. When the power supply 33 is applied to the equipment 30, the power is supplied to a relay circuit 35 to switch a changeover switch 32 to the NO side from the NC side. Thus the line 3a is connected to an interface control circuit 34 and the equipment 30 starts reception of the data led out to the line 3a from the system 20.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a system in which power on/off of a power supply device of a terminal device is controlled by instructions from a remote device connected via a data line. In particular, the present invention relates to a system for controlling power on/off of such a system.

(Prior art) In computer systems, terminal devices such as printing devices connected to the center system are rarely in operation all the time, and output operations such as printing are performed all at once once a certain amount of data has been collected. It is often operated using batch processing.

In this type of usage, it is more economical to turn off the power to the terminal device when it is not operating.

However, it is not reasonable for the operator to intervene and handle the power supply bureaucracy each time, so by equipping the terminal device with a power control device, the terminal device can be automatically controlled by commands from the center system, which is a remote device. Controls the power on/off of terminal devices.

FIG. 4 is a diagram showing a computer system in which such control is performed. As shown, the computer system consists of a center system 2 and a terminal device l connected thereto.

FIG. 5 is a block diagram showing details of the power-on control portion of the terminal device 1 in FIG. 4. In the figure, 3 is a receive data line from the center system, 11 is an interface control circuit that receives and decodes the receive data from the receive data line 3, and 13 is a power source for turning on the terminal device according to a command from the center system. It is a control circuit. 12 and 14 are power supply devices for supplying power to the interface control circuit 11 and the power supply control circuit 13, respectively.

The power supply device 12 receives a control signal P- from the power supply control circuit 13.
The stain source is turned on when it is turned ON, and the power is turned off when the control signal P-OFF from the interface control circuit 11 is turned on. Further, the power supply device 14 is a power supply dedicated to the power supply control circuit 13, and is composed of, for example, a battery.

15 is a changeover switch, and 1.16 is a relay circuit. The changeover switch 15 is a relay contact switch that operates in conjunction with the relay circuit 16.
When there is no relay drive signal RL-ON from 3, the changeover switch 15 is turned to the NC side. Changeover switch 15
When the is turned to the NC side, the reception data line 3 is connected to the power supply control circuit 13, and the changeover switch 15 is turned to the NC side.
When it is on the C side, the interface control circuit 1
1.

Next, the power-on operation will be explained step by step. First, the discussion will proceed assuming that the changeover switch 15 is turned to the NC side and the reception data line 3 is connected to the power supply control circuit 13. When the center system 2 wants to turn on the terminal device 1, it sends out a certain data pattern.

The power supply control circuit 13 compares the data received at this time with predetermined data indicating power-on, and if they match, it issues a power-on instruction signal P-ON and powers on the power supply device 12.

Power is supplied from the power supply device 12 to the interface control circuit 11, and at this time the interface control circuit 11 starts operating. At the same time, the power supply control circuit 13 sends a relay drive signal RL-ON to the relay circuit 16 to switch the changeover switch 15 from the NC side to the NC side. Thereby, the reception data line 3 is electrically connected to the interface control circuit 11, and data communication between the center system 2 and the terminal device 1 becomes possible. Further, the power to the terminal device l is cut off by transmitting predetermined data instructing power cut off from the center system 2. In the interface control circuit 11, if the received data is data instructing power-off, a power-off instruction signal P is output.
-OFF is issued to turn off the power to the power supply device 12.

In addition, as another conventional method for controlling power on/off, instead of providing a power control circuit as described above in the terminal device, a signal instructing power on/off is sent to the center system 2. There is a system that remotely turns on/off the power to the terminal device 1 from the center system 2 by transmitting the information to the terminal device 1 via a dedicated wiring provided between the center system 2 and the terminal device 1 . This method has the advantage that there is no need to provide a power control circuit that requires constant power supply.

(Problems to be Solved by the Invention) However, the conventional power on/off control described above has the following problems.

(b) In systems where a power control circuit is provided in the terminal device, power must be constantly supplied to the power control circuit. Therefore, in addition to the power supply device that supplies power to the entire terminal device, it is necessary to provide a power supply device (for example, a battery) exclusively for the power control circuit in the terminal device, which increases costs and reduces the size of the terminal device. There is a problem in that it interferes with

Further, the power supply control circuit requires hardware for determining received data and controlling power-on, making it relatively expensive.

(b) In the method of connecting the center system and the terminal equipment using dedicated wiring for power control, this wiring must be installed separately from the data line, and the wiring for this usually requires many electric wires. This is not a practical power control method due to its high cost.

Therefore, the present invention solves the above-mentioned conventional problems, and in particular allows the terminal device to be turned on with a simple configuration without requiring the above-mentioned power supply control circuit or special wiring. On the other hand, it is an object of the present invention to provide a system that can be controlled by instructions from a remote device such as a remotely installed center system.

(Means for Solving the Problems) The present invention is directed to a system in which power on/off of a power supply device of a terminal device is controlled by instructions from a remote device connected via a data line.

In such a system, the present invention first forms the data line into a loop shape. Second, in the terminal device, a receiving means for receiving a power-on instruction signal transmitted from a remote device to a data line, and an interface control circuit for receiving a data signal on the data line from the receiving means are connected to the switching data line. A switching means is provided.

The switching means connects the data line and the receiving means before powering on the terminal device, and when the receiving means receives the power-on instruction signal, turns on the power to the voltage power supply device, and
After the power is turned on, the switching means is switched to connect the data line and the interface control circuit.

(Operation) When powering on the terminal device, the remote device sends a power-on instruction signal to the loop-shaped data line. The switching means of the terminal device connects the data line and the receiving means before the power is turned on. Then, power on the power supply device. Accordingly, the switching means switches to connect the data line and the interface control circuit. As a result,
A powered-on terminal device can receive data from a remote device.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention. Terminal device 20 and center system 30 data lines 3a, 3
Connected by b. Data line 3a.

3b are each formed into a loop shape. data line 3
The data line a transmits data from the center system 20 to the terminal device 30, and the data line 3b transmits data from the terminal device 30 to the center system 20. The center system 20 is
It has a resistor 21 and a driver 22 connected to the data line 3a as shown. One end of the resistor 21 is connected to the power supply voltage +
VCC is supplied. The driver 22 is the center system 2
Transmit data of 0 is sent to the data line 3a. driver 2
2 is an open collector output, and is configured so that when the transmission data, which is the input signal of driver n, reaches %1, the internal output transistor (not shown) turns on, and the output level becomes OV. . In this way, by setting the output of the driver 22 to Ov, a power-on instruction signal to the terminal device 30 is created. The center system 20 also includes a receiving circuit 23 connected to the data line 3b. The receiving circuit 23 is formed of a photocoupler. The output of the receiving circuit 23 is connected to a signal processing section (not shown).

The terminal device 30 is configured as follows. The other end of the data line 3a connected to the resistor 21 of the center system 20 is connected to the anode of a photodiode 31a of a receiving circuit 31 composed of a photocoupler. Further, the cathode of the photodiode 31a is connected to the NC side of the changeover switch 32. The collector and emitter of the transistor 31b of the receiving circuit 31 are connected to input terminals a and b of the power supply device 33, respectively. The power supply device 33 is configured to turn on the power when the input terminals a and b become electrically connected. At this time, the power is turned on and power is supplied to the interface control circuit 34 and the relay circuit 35. Further, the power to the power supply device 33 is cut off by the control signal P-OFF of the interface control circuit 34 instructing the power cut.

The interface control circuit 34 receives and processes data on the data line 3a. The input section of the interface control circuit 34 has a photocoupler 34a, the anode of the photodiode of the photocoupler 34a is connected to one end of the data line 3a, and the cathode is connected to the No side of the changeover switch 32. The switching of the changeover switch 32 corresponds to the operation of the relay circuit 35, and before the terminal device 30 is powered on, it is turned to the NC side as shown in the figure. The terminal device 30 also includes a resistor 36 and a driver 37 connected to the data line 3b.
has. The resistor 36 and driver 37 are similar to the resistor 21 and driver 22 of the center system 20, respectively.

FIG. 2 is a diagram showing a detailed configuration of the power supply device 33 shown in FIG. 1. The latch circuit 40 is for holding a pulse signal, and its input is connected to the collector of the transistor 31b of the receiving circuit 31 via the input terminal a of the power supply device 33. Note that the input terminal is grounded. The latch circuit 40 clears the holding of the pulse signal in response to the power-off instruction signal P-OFF from the interface control circuit 34.

The relay circuit 41 is operated by the output signal of the latch circuit 40. The power supply circuit 42 inputs AC power and connects the terminal device 3
A predetermined power supply voltage is supplied to the inside of 3. One input of the power supply circuit 42 is connected to an AC power supply via a three-pole thyristor (hereinafter simply referred to as a thyristor) 43.

Furthermore, a resistor 44 and a relay contact 45 of the relay circuit 41 are connected in series between the gate of the thyristor 43 and one input of the power supply circuit 42 .

Next, the operation of the embodiment having the above configuration will be explained with reference to a diagram showing the operation timing shown in FIG.

In FIG. 1, when the terminal device 30 is powered off, the relay circuit 35 is not operating, and the changeover switch 32, which is the contact point of the relay circuit 35, is tilted toward the NC side. When the center system 20 turns on the power of the first terminal device 30, the transmission data is first set to sIN. As described above, the driver 22 has an open collector output, and when the transmission data that is the input signal to the driver 220 reaches 11, the output transistor turns on and the output level becomes Ov. When the output transistor of the driver 22 is turned on, a current flows from the power supply +vo0 of the center system 20 toward the driver 22 through the loop-shaped data line 3a. Therefore, the photodiode 3 of the receiving circuit 31
1a emits light, and conduction occurs between the collector and emitter of transistor 31b. This corresponds to the control signal P-ON changing from high level to low level (third
Figure (a)). As a result, a between the input terminals of the power supply device 33
-b is conductive. Then, the latch circuit 40 shown in FIG.
When the input terminals a and b become conductive, the output changes from low level to high level (FIG. 3(C)).

As the output of the latch circuit 40 becomes high level, the relay circuit 41 is activated (FIG. 3(d)), and the relay contact 45 of the relay circuit 41 is closed. As a result, AC power is input to the power supply circuit C, and the terminal device 33 is turned on (FIG. 3(e)). When the power is turned on, the power supply device 33 supplies power to the relay circuit 35. Then, the relay circuit 35 becomes conductive and switches the selector switch 32 from the No side to the NC side. Accordingly, the data line 3a is connected to the interface control circuit 34, and the terminal device 30 can receive the data sent from the sentan stem 20 to the data line 3a. At this time, data is transmitted from the terminal device 30 to the center system 20 via the data line 3.
This is done via b.

When the center system 20 turns off the power to the terminal device 30, the center system 20 disconnects the data line 3 as in the conventional case.
A signal instructing to turn off the power of the terminal device 30 is sent to a. When the interface control circuit 34 receives this signal, it outputs the control signal P-OFF to the latch circuit 4 of the power supply device 33.
0 (Fig. 3(b)).

As a result, the output of the latch circuit 40 changes from high level to low level (FIG. 3(C)). Therefore, the power is not supplied to the relay circuit 41, and the relay circuit 41 is turned off (FIG. 3(d)). Therefore, the relay contact 45 opens and the power supply circuit 42 is disconnected (FIG. 3(e)).

One embodiment of the present invention has been described above. The present invention can be implemented in various systems in addition to computer systems. Further, the number of terminal devices 30 is not limited to one, and the present invention can be similarly implemented even in a system in which a plurality of terminal devices 30 are connected to a loop-shaped data line.

(Effects of the Invention) As explained above, according to the present invention, the following effects can be obtained.

(b) In the present invention, the data line is looped, and before the power of the terminal device is turned off, a receiving means for receiving a power-on instruction signal from a remote device is provided in the loop. There is no need to constantly drive it with a power supply.

That is, the receiving means only needs to detect the presence or absence of current in the loop, and for this purpose, it can be constructed from a simple element that does not require a power source. Therefore, there is no need for a conventional power supply control device that is always driven by a dedicated power source and has the function of determining the content of data, making it possible to downsize the terminal device, simplify the power supply device, and reduce the cost.

(b) Since the configuration is such that the data line is shared for the power-on instruction signal from the remote device to the terminal device without providing dedicated wiring, the wiring within the system can be simplified.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a diagram showing the detailed configuration of the power supply device shown in FIG. 1, FIG. 3 is a diagram showing the operation timing of this embodiment, FIG. 4 is a diagram showing the configuration of a computer system, and FIG. 5 is a block diagram of a power-on control section according to the prior art. 20... Center system, 21... Resistor, 22.
... Driver, 23... Receiving circuit, 30... Terminal device, 31... Receiving circuit, 32... Selector switch, 3
3...Power supply device, 34...Interface circuit, 3
5... Relay circuit, 36... Resistor, 37... Driver, 40... Latch circuit, 41... Relay circuit, 42... Power supply circuit, 43... 3-pole direction thyristor, 44...Resistor, 45...Relay contact.

Claims (1)

[Scope of Claims] In a system in which power on/off of a power supply device of a terminal device is controlled by an instruction from a remote device connected via a data line, the data line is formed in a loop shape and the terminal device is connected to the terminal device. , comprising a receiving means for receiving a power-on instruction signal sent from a remote device to a data line, and a switching means for connecting the receiving means and an interface control circuit for receiving a data signal on the data line to the switching data line; The means connects the data line and the receiving means before powering on the terminal device, and the receiving means turns on the power to the power supply device when receiving the power-on instruction signal, and after the power is turned on, switches the switching means to transmit the data. A power-on control method characterized by connecting a line and an interface control circuit.