JPS63163913A - Terminal device power control circuit - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION (AlIndustrial Field of Application) This invention relates to a power supply control circuit for a terminal device that is remotely controlled by a control device such as a personal computer, and in particular, the invention relates to a power supply control circuit for a terminal device that is remotely controlled by a control device such as a personal computer. This invention relates to a power supply control circuit for a terminal device that can be controlled by a terminal device.

(b) Conventional technology In conventional remote control systems, control such as turning on and off the power on the terminal device side and starting up the system is performed on the control device side using a communication line. First, procedures for line connection are performed, and once the data link is established, this is done using a command method. In other words, control is performed by sending commands from the control device to the terminal device after establishing a data link, whether it is powering on the terminal device, starting up the system, or sending text or display data. was doing.

(C1 Problem to be Solved by the Invention) However, the above-mentioned remote control system has a drawback in that power must always be supplied to the transmission circuit of the terminal device.

This invention focuses on the fact that in the control line of a communication line consisting of a control line and a data line, there is usually a control line that rises before data transmission, and uses the rise of this control line to turn on the power on the terminal device side. An object of the present invention is to provide a power supply control circuit for a terminal device that performs control and does not require constant power supply to a transmission circuit or the like.

(d) Means for Solving the Problems This invention provides a remote control system in which a terminal device and a control device are connected by a communication line consisting of a control line and a data line, in which one of the control lines before data transmission A relay is installed on the terminal device side, through which the rising control line signal is guided to the drive terminal.
The present invention is characterized in that this relay output terminal is connected to a power-on terminal of a terminal device power supply circuit.

(81 Effect) In the power supply control circuit for a terminal device according to the present invention, when data (including text, commands, etc.) is to be transmitted from the control device to the terminal device, first, the control line that is activated before data transmission is activated. line, that is, a control line that notifies the terminal device that the control device side is ready to send data.The most typical communication line consisting of a control line and a data line is R3-23.
This line is based on the 2-C standard. Based on R3-232-0 (this control line is called DTP (Data Terminal Ready).

In the terminal device, when this DTR signal rises, the relay turns on, and the relay output turns on the power supply circuit.

Power-on control of the terminal device is performed through the simple operation described above. Note that to turn off the power, the falling edge of this DTP signal may be used to turn off the power, but it is also possible to control the power off using a normal command system. If you control the power off using commands,
The power of the terminal device is turned off every time data communication from the control device is completed. In this embodiment, a terminal device equipped with a display is used, and a power supply control circuit that performs power-off control by a command is shown. Also, as a communication line, R3-232
-C line is used.

FIG. 1 shows a block diagram of a remote control system to which this embodiment is applied.

1 is a control device consisting of a personal computer. R3-232-
Of the control lines of communication line 2 of C, the DTR line, which is a data terminal ready signal line, is connected to the transmission circuit and CPU on the terminal device 3
It is connected to the line connection terminal of the terminal device control circuit 30 including
It is output to the input terminal (relay drive terminal) of SR (solid state relay) 31. The output of this 5SR 31 is led to the power-on terminal of the power supply circuit 32 of the terminal device 3, and the power supply circuit 32 is turned on by this relay output.

The terminal device control circuit 30 starts operating when the power supply circuit 32 is turned on. The terminal device control circuit 30 also includes a pulse generation circuit that generates a pulse after a certain period of time after supplying the power supply voltage, and outputs a cent pulse to the keep relay 33 by this pulse generation circuit. Note that this pulse generation circuit can be constructed from a known simple circuit using a CR element or the like, but the pulses may also be generated by software. The keep relay circuit 33 latches this cent pulse and holds the input terminal of the 5SR31 at "H" via the diode D2. When the keep relay 33 is set, an OR circuit is formed by the diode D1 and the diode D2, so even if the power on the control device side is interrupted, the power on the terminal device side is maintained. Note that the terminal device control circuit 3
A display 34 is connected to the terminal 0 and performs display based on data sent from the control device 1 through the TXD line, which is a data line.

FIG. 2 shows a block diagram of the 5SR31.

The DTR signal input via diode Di is 5SR3
1 and drives the photocoupler PC. The zero cross circuit 31a operates when there is an output from the kito coupler PC, and the output circuit 3 including the tritic
Drive 2a. The zero-cross circuit 31a sets the conduction angle of the triac of the output circuit 32a based on the output level of the photocoupler PC with reference to the zero-cross timing of the power supply E. In this embodiment, the output level of the photocoupler PC is not a problem, and the triac is made conductive at a 100% conduction angle when this PC output is present. When the triac becomes conductive and the output circuit 32a is turned on, the power supply circuit 32
The power-on terminals a and b become conductive, and power is supplied to the load. Note that the load corresponds to the DC voltage generation circuit.

Next, the operation of this embodiment will be explained with reference to FIG. This figure is a diagram showing a timing chart of main parts on the terminal device side.

When trying to send data from the control device 1 to the terminal device side for the first time, the DTP at timing t before sending the data.
Stand up at 1. The terminal device side receives this signal and performs 5S
R31 turns on. This turns on the power supply circuit 32 and supplies DC power to the terminal device control circuit 30.

As mentioned above, since the terminal device control circuit 30 is provided with a pulse generation circuit, the keep relay 33 is set at t2, which is a certain time T (this time is set to be very short) after the timing t1. Generates a pulse. The keep relay 33 is sent at this timing t2, and the input of the 5SR31 is “■(
The diode D1 is turned off from the moment the output of the keep relay 33 rises to “H”.
The TR signal is now supplied only to the terminal device control circuit 30. As shown in FIG. 2, when the power supply circuit is turned on, it is necessary to drive the photocoupler PC with the DTR signal, but depending on the magnitude of the DTR output current of the control device 1, the photocoupler PC and the terminal device control circuit 30 (If the data transmission direction is unidirectional, this input terminal becomes a DTR terminal) and the input terminal of the DTR terminal may not be able to be driven at the same time. However, in this embodiment, immediately after the keep relay 33 cents, the cent output causes 5S
Since R31 is kept in the on state and the diode DI is made non-conductive, all the drive current of the DTR terminal of the control device 1 can be output to the terminal device control circuit 30. Therefore, the above problem does not occur.

After the DTR signal rises, the terminal device side sends DSR
A (data cent ready) signal is sent to the control device 1. The rise of this DSR signal is caused by the keep relay 33.
This is after supplying a set pulse to . Control device 1
After confirming that this DSR signal has risen, it starts transmitting data to the terminal device side.

When the control device 1 finishes transmitting data to the terminal device side and intends to turn off the power to the terminal device 3, a power off command is sent as transmission data. When the terminal device control circuit 30 receives this power off command, it generates a reset pulse to the keep relay 33 according to a program. t3 is the timing at which the reset pulse is generated. At this timing t3, the keep relay 33 turns off and the 5SR
31 input falls to “L”. That is, the power supply circuit 32 is turned off and power supply to the terminal device control circuit 30 is stopped. Note that the DTR signal is turned off before the reset pulse is generated.

When the terminal device 3 is in the power off state, the terminal device 3
When attempting to transmit data again to the computer, the power supply circuit 32 is turned on using the above procedure using the DTR signal.
After that, 5SR31 by keep relay 33 in the terminal device.
remains on.

With the above operation, there is no need for the control device 1 to create a special command to turn on the power to the terminal device, and data can be sent while always assuming that the terminal device is powered on. I can do it. Therefore, there is no need for any communication protocol for turning on the power, which reduces the burden on the control device l side, and the terminal device side can easily turn on the power without having to have a complicated circuit configuration.

Note that on the terminal device side, the DTR signal may be supplied to the terminal device control circuit 30 and 5SR 31 via a buffer to which power is always supplied. In this way, the photocoupler PC and the DTR terminal of the terminal device control circuit 30 can be simultaneously driven by the buffer output, and a holding circuit using a keep relay as in the above embodiment can be made unnecessary. However, in this case, it is necessary to constantly supply power to the buffer, and
When the data transmission from the control device 1 is completed, the DTR signal also drops, so that the power of the terminal device is always turned off.

(g) Effects of the Invention As described above, according to the present invention, there is no need to supply power to any part of the terminal device (especially the transmission circuit section) before the power is turned on, thereby reducing power consumption. (This makes it particularly useful when the power supply circuit is configured with a battery or the like.)

Further, on the control device side, there is no need to create a special command etc. when turning on the power of the terminal device, and there is no need to provide a special control line for power-on control on the communication line. Furthermore, on the terminal device side, it is basically only necessary to provide a relay that is driven by a signal from one control line. This has the advantage that the configuration is extremely simple.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram of a remote control system according to an embodiment of the present invention, FIG. 2 is a block diagram of an SSR, and FIG. 3 is a timing chart of main parts on the terminal device side. 1-control device, 2-communication line (R3-232-C), 3-terminal device, 3l-3SR (solid state relay).

Claims (1)

[Claims] (1) In a remote control system in which a terminal device and a control device are connected by a communication line consisting of a control line and a data line, a relay in which the signal of the control line that rises before data transmission among the control lines is guided to the drive terminal. is provided on the terminal device side,
A power control circuit for a terminal device, characterized in that the relay output terminal is connected to a power-on terminal of a power supply circuit for the terminal device.