JPS60233955A - Code transmission system - Google Patents

Abstract

PURPOSE:To attain stable reception even if noises are superimposed by transmitting a signal to reset a Schmitt circuit before a master station equipment transmits a prescribed remote signal. CONSTITUTION:A transmission processing circuit 11 of the master station equipment 10 commands the transmission of a reset signal to a reset signal generating circuit 12. The circuit 12 transmits the reset signal to a slave station equipment 30-1 via a transmission interface circuit 13 and a transmission line 20. When the reset signal from the device 10 is received by a differentiation circuit 32 via a reception interface circuit 31, the circuit 32 converts the signal into a bipolar trigger pulse signal and outputs it to the Schmitt circuit 33. When the reset signal is inputted to the circuit 33, the circuit 33 changes the state of the system into the reception enable state even when the circuit 33 is inverted into the reception disable by the noise in the transmission line 20.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a code transmission system, and more particularly, to a code transmission system that enables stable reception even when noise is superimposed on a transmission path.

(Prior art 2 and its problems) - When the monitored control device (hereinafter referred to as slave station device) has the differentiating circuit and the Schmitt circuit in addition to the receiving input/transfer chair circuit and the receiving processing circuit. However, the Schmitt circuit has the disadvantage that it malfunctions when noise is superimposed on the transmission path. Fig. 1 is an explanatory diagram of this case. Noise is superimposed on the transmission path, the seamit circuit malfunctions, and the slave station device receives the first signal from the remote monitoring and control device (hereinafter referred to as the master station device). This indicates a state in which a remote monitoring control signal (hereinafter abbreviated as remote signal) cannot be detected.

(Object of the Invention) An object of the present invention is to provide a code transmission system which solves all of the above-mentioned drawbacks and allows the slave station device to perform stable reception.

(Structure of the Invention) The present invention is characterized in that it includes the differentiation circuit and the Schmitt circuit, and the master station device transmits a signal for resetting the Schmitt circuit before transmitting a predetermined remote signal.

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

FIG. 2 is a block diagram showing one implementation fII of the present invention.

In this embodiment, zero slave station devices 30 (30-1 to n) are connected, but only one slave station device 30 (3o-1) is shown to avoid complication of the drawing.

FIG. 3 is a time chart showing the relationship between the reliability of seven bits on the transmission path and the remote signal. FIG. 4 shows an example of a signal for cents in the case of the start-stop synchronization method.

The transmission processing circuit 11 of the master station device 10 instructs the reset signal generation circuit 12 to transmit a reset signal. The reset signal generation circuit 12 sends the reset signal to the slave station device 3 via the transmission interface circuit 12 and the transmission path 20.
Send to 0-1.

When the differentiating circuit 32 of the slave station device 30 - 1 receives the reset signal from the master station device 10 via the receiving interface circuit 31 , it converts it into positive and negative trigger pulse signals and outputs them to the Schmitt circuit 33 .

When the reset signal is input, the Schmitt circuit 33 traps the receivable state even if the state is reversed to the unreceivable state due to transmission line noise.

After transmitting the signal for the transmission processing circuit 11 of the master station device 10, the interface circuit 13 immediately transmits the remote signal.
and is transmitted to the slave station device 30-1 via the transmission path 20.

When the differentiating circuit 32 of the slave station device 30 - 1 receives the remote signal from the master station device 10 via the reception interface circuit 31 , it converts it into positive and negative trigger pulse signals and outputs them to the Schmitt circuit 33 . The Schmitt circuit 33 converts the positive and negative trigger pulse signals into waveform-shaped reception pulse signals in a receivable state and outputs the converted reception pulse signals to the reception processing circuit 34 . The reception processing circuit 34 decodes the received pulse signal and performs a predetermined operation.

The master station device performs the same operation with the next slave station device 30-2 according to the procedure described above. Thereafter, the same operation is repeated for the subsequent slave station devices 30-3 to 30-n.

In the above explanation, it was explained that there is a time difference between the reset signal and the remote signal, but the present invention can be applied even when there is no time difference.

(Effects of the Invention) As described above, the present invention provides, in a signal transmission method using a slave station device equipped with the differentiation circuit and the seam circuit, before the master station device transmits a predetermined remote signal.
By transmitting a signal for resetting the Schmitt circuit, there is an effect that stable reception can be achieved even if noise is superimposed on the transmission path before the slave station device receives the remote signal.

[Brief explanation of the drawing]

Fig. 1 is a time chart showing a state in which a Trap Schmitt circuit malfunctions when noise is superimposed on the transmission path in a conventional signal transmission system. Fig. 2 is a configuration diagram showing an embodiment of the present invention. FIG. 3 is a time chart of the reset signal and remote signal, and FIG. 4 is an example of the reset signal. 10... Master station device, 20... Transmission line,
30.30-1~n...Slave station device, 11...
... Transmission processing circuit, 12 ... Reset signal generation circuit, 13 ... Transmission interface circuit, 31 ... Reception interface circuit, 32.
... Differential circuit, 33 ... Schmitt circuit,
34... Reception processing circuit.

Claims (1)

[Claims] A remote monitoring control device and a monitored controlled device are connected via a transmission line 1, and the monitored controlled device further includes a differentiating circuit that converts a received pulse signal into a positive and negative trigger pulse signal IC, and a differentiating circuit that converts the received pulse signal into a positive and negative trigger pulse signal IC. It is characterized by comprising a Schmitt circuit that converts received pulses into waveform-shaped received pulses, and the remote monitoring control device transmits a signal for resetting the Schmitt circuit before transmitting a predetermined remote monitoring control signal. code transmission method.