JPH04268829A - Data transmitting method - Google Patents

Abstract

PURPOSE:To make a slave station power-sourceless by supplying power from a master station to the slave station through a transmission line. CONSTITUTION:Plural slave stations (slave transmitting station 6 and slave receiving station 7) are connected to one transmission line 5 connected to the master station 4 to be a main station. A power supply pulse A higher than a data pulse for carrying data in a peak value is sent from the master station 4 to the transmission line 5 at prescribed intervals, and at a slave station side, the charge of the above-mentioned power supply pulse A is accumulated by a capacitor 25, and is made driving power. Besides, at the point of time of the end of the power supply pulse A, both the terminals of the transmission line 5 are turned into a state terminated by characteristic impedance by the reverse bias action of a diode 24 so that a high-speed digital signal can be transmitted, and data is transmitted between the maintain station 4 the slave station as inserting the data between the power supply pulses A.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a method of connecting a plurality of slave stations to a single transmission line connected to a master station and transmitting data between the master station and the slave stations, and particularly relates to a method for transmitting data between the master station and the slave stations. The present invention relates to a data transmission method in which driving power is also supplied via a transmission path.

0002

[Background Art] A master station that issues control commands and multiple slave stations equipped with small devices such as various sensors and actuators are connected via a transmission path, and data is transmitted from the master station to the slave stations. In addition, the master station collects data from the slave stations.

0003

[Problem to be Solved by the Invention] In order to send data from the slave station to the transmission line, it is necessary to either equip the slave station with a power supply section or
Alternatively, it is necessary to run power wiring from the master station to each slave station, but if a large number of slave stations are scattered, it would be expensive to provide a power supply section for each slave station. ,
Furthermore, if separate wiring is required for power supply from the master station to each slave station, a large amount of wiring material is required, which is time-consuming.

[0004] In view of the above points, the present invention provides a data transmission method with the aim of supplying power from a master station to a slave station via a transmission line so that the slave station does not need a power source. be.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the present invention connects a plurality of slave stations to one transmission line connected to a master station, and transmits the peak value from the master station to data for data transmission. A power pulse that is sufficiently higher than the power pulse is sent to the transmission line at a predetermined interval, and in each slave station, the charge of the power pulse is accumulated in a diode and a capacitor to serve as driving power for the slave station, and at the end of the power pulse, the diode is reverse biased. Due to this action, both ends of the transmission path are terminated by characteristic impedance, enabling high-speed digital signal transmission, and the data to be transmitted is inserted as a data pulse between the power pulses and sent out to the transmission path, thereby performing data transmission. This is how it was done.

[0006]

In the data transmission method according to the present invention, power pulses having a sufficiently higher peak value than data pulses are sent from the master station to the transmission path at predetermined intervals. In the slave station, the electric charge of the power supply pulse is accumulated by a diode and a capacitor, and is used as driving power for the slave station. This eliminates the need for a power supply device for the slave station. At the end of the power pulse, both ends of the transmission path are terminated with characteristic impedance due to the reverse bias effect of the diode, making it possible to transmit high-speed digital signals. Data transmission between the master station and the slave station is performed by inserting data pulses between the power pulses.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic configuration of the entire apparatus that employs the data transmission method according to the present invention, in which the control device 1 has an RS23 serial interface for communication.
Equipped with 2C interface 2, the RS232
A transmission section 3 is connected to the C interface 2.

The data transmission unit 3 connects a master station 4, which is a main station, to a single transmission line 5 made of twisted pair wires or coaxial cables.
A plurality of slave transmitting stations 6 are connected to the transmission path 5.
and slave receiving station 7 are connected, and these slave transmitting station 6 and slave receiving station 7 share one transmission path.

The master station 4 of the transmission section 3 includes a power pulse generating section 8 for generating a power pulse A having a peak value of 30V as shown in FIG. 2, and a data pulse receiving section for receiving a data pulse B having a peak value of 10V. 9, a data pulse transmitter 10 for transmitting data pulses B, a counter section 11 for counting pulses, and a transmission/reception setting section 12 for setting a transmitting/receiving station of a slave station, and a power supply section 13 for driving these. .

The child transmitting station 6 is provided with a power pulse detection section 14 for detecting the power pulse A, a station number setting section 15 for setting its own station number unique to each child transmitting station 6, and a counter section 16 for counting pulses. , an oscillator 17 common to each child transmitting/receiving station so that each child transmitting/receiving station generates an accurate clock of the same phase and frequency, and a data pulse sending section 18 for sending data pulse B to the transmission line 5 are provided.

The child receiving station 7 is also provided with a power pulse detection section 19 for detecting the power pulse A, a station number setting section 20 for setting the own station number unique to each child receiving station 7, and a station number setting section 20 for setting the own station number unique to each child receiving station 7. It is provided with a data pulse receiving section 21 for receiving data, an oscillator 22 common to each transmitting/receiving station for generating accurate clocks with the same phase, and a counter section 23 for counting pulses.

The connection between the child transmitting station 6 and the child receiving station 7 and the transmission line 5 is constituted by a circuit in which a diode 24 and a capacitor 25 are connected in series, as shown in FIG. Power supply circuits (not shown) of the transmitting station 6 and slave receiving station 7 are coupled.

Next, the master station 4, the slave transmitting station 6, and the slave receiving station 7
Data transmission between the two will be explained.

First, the station number setting section 15 of each child transmitting station 6 and the station number setting section 20 of the child receiving station 7 are set with their own station numbers representing their respective station numbers, and one transmission path 5 is set from each child transmitting station 6. In order to send out data in a well-timed and orderly manner, a time difference at the time of data sending is set in correspondence with the own station number of each child transmitting station 6. The set station number and the time difference at the time of data transmission are also stored in the master station 4, and the multiple data transmitted from each child transmitting station 6 are separated based on the time difference and unique to each child transmitting station 6. Make it possible to understand the data.

Furthermore, since the master station 4 sequentially sends a plurality of data to each child receiving station 7 to one transmission line 5, in order to prevent data from being mixed up, each child receiving station 7 is Set the time difference when sending data corresponding to the number. Furthermore, each child receiving station 7 also stores the time difference corresponding to the own station number of the set time difference as the time difference at the time of data acquisition of the own station, and selects the time difference from among the plurality of data transmitted from the master station 4. Make it possible to retrieve your own station's data based on .

Then, a power pulse A having a peak value of 30V, which is sufficiently higher than the peak value of the data pulse B, as shown in FIG. 3, is sent from the master station 4 to the transmission path 5 at predetermined intervals. In each child transmitting station 6 and child receiving station 7, when the power pulse A begins to rise and the potential of the transmission line 5 becomes sufficiently higher than the potential of the data pulse B, the direction of the potential of the diode 24 becomes forward biased, and the charge of the power pulse A increases. diode 24
through the capacitor 25 and begins to accumulate the charge obtained from the power supply pulse A. As shown in FIG. 3, the power supply pulse A takes charge and charges the capacitor 25.
At the end of the fall of the power supply pulse A, the diode 24 in FIG. 4 becomes reverse biased and the inflow of charge stops, and the influence of the capacitor 25 on the transmission line 5 can be ignored, and the characteristics of both ends of the transmission line 5 are reduced. Enables high-speed digital signal transmission by terminating with impedance. The charge accumulated in the capacitor 25 is used as driving power for the child transmitting station 6 and the child receiving station 7.

Next, a procedure for transmitting data from slave transmitting station 6 to master station 4 will be explained.

Each slave transmitting station 6 detects the end point of the power pulse A by the power pulse detector 14, and causes the oscillators 17 of all slave transmitting stations 6 to oscillate simultaneously to generate clocks of the same phase and frequency. The clocks of the oscillators 17 are accurately synchronized. Then, based on this clock pulse, the counter section 1 calculates the time difference corresponding to the preset own station number.
6, and the data to be sent to the master station 4 after a time difference set for each child transmitting station 6 has elapsed is sent to the transmission path 5 as a data pulse B via the data pulse sending unit 18. Figure 2
is a transmission waveform diagram showing a state in which data pulse B is inserted between power pulses A, data pulse B is sent from three slave transmitting stations 6 to transmission line 5 with a time difference, and slave transmitter The own station number (1) of station 6 is in the (1) part, the own station number (2) is in the (2) part, and the own station number (
3) is inserted into the part (3) and is being transmitted. Note that the part (0) is secured as a data stability period.

[0020] Then, in the master station 4, a data pulse receiving section 9
When the data pulse B transmitted from each child transmitting station 6 is received, the data pulse B is transmitted to each child based on the time difference corresponding to the station number of each child transmitting station 6, which is stored in advance while synchronizing with the power pulse A. The data pulses B are counted for a certain period of time by the counter section 11 while being separated for each station 6,
This allows data from each transmitting station 6 to be read. This read data is then sent to the control device 1 via the RS232C interface 2.

Next, a procedure for transmitting data from the master station 4 to the slave receiving station 7 will be explained.

When data is output from the control device 1 to the master station 4 via the RS232C interface 2, the master station 4 uses a clock pulse synchronized with the power pulse A, which is set in advance for each child receiving station 7. A counter section 11 counts the time difference at the time of data transmission. Then, when the time set for each child receiving station 7 has elapsed, the data to be transmitted to each child receiving station 7 is sent to the data pulse B via the data pulse transmitter 10.
The data are sequentially sent out to the transmission path 5 as the data. This transmission is performed by inserting the transmission data with a time difference between the power pulses A as shown in FIG. The data for the own station number (1) of 7 is in the part (1), and the own station number (2) of the slave receiving station 7 is included in the part (1).
The data to (2) contains the own station number of the slave receiving station 7 (
The data for 3) is inserted into part (3) and transmitted. Note that the position (0) is secured as a data stable period as described above.

When each child receiving station 7 receives a pulse signal from the master station 4, the power pulse detection unit 19 detects the end point of the power pulse A, and causes the oscillators 22 of each child receiving station 7 to oscillate at the same time. Clocks with the same phase and frequency are generated, and the clocks of the respective oscillators 22 are accurately synchronized. Then, the data acquisition time stored in the slave receiving station 7 is counted by the counter unit 23 based on the clock pulse from the end of the power pulse A, and when the data acquisition time has come, the data pulse reception unit 21 uses the data pulse B
The data to be transmitted from the master station 4 is obtained by starting reading the data of the own station from among the plurality of data of the base station 4 and counting data pulses B for a certain period of time.

[0024] In the above embodiment, the slave transmitting station 6,
Although an example has been given in which the slave receiving stations 7 are provided separately, the slave stations may also serve as transmitting and receiving stations. Furthermore, FIG. 5 is a diagram showing another embodiment in which the connection format of the transmission line shown in FIG. 4 is modified. Even if a different connection type is adopted, the essence of the present invention does not change, and it goes without saying that the present invention includes various modifications without departing from the gist of the present invention.

[0025]

As described above, according to the data transmission method according to the present invention, a slave station is connected to one transmission line 5 connected to the master station 4 serving as the main station, and a slave station is connected to the transmission line 5 from the master station 4. Since the charge of the power pulse A sent to the slave station is accumulated in the slave station and used as driving power for the slave station, there is no need to equip the slave station with a power supply device, and wiring for power supply from the master station 4 is not required. There is no need to provide it separately, and the effort and cost required for wiring can be reduced.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing an embodiment of the method of the present invention.

FIG. 2 is a transmission waveform diagram showing the relationship between power pulses and data pulses.

FIG. 3 is a transmission waveform diagram of power pulses.

FIG. 4 is an explanatory diagram showing a connection section between a transmission path, a child transmitting station, and a child receiving station.

FIG. 5 is an explanatory diagram showing another example of connection between a transmission path, a child transmitting station, and a child receiving station.

[Explanation of symbols]

1 Control device 3 Transmission section 4　　　　　　Master station 5 Transmission line 6 Child transmitting station (child station) 7. Child receiving station (slave station)

Claims (1)

[Claims] Claim 1: A plurality of slave stations are connected to one transmission line connected to a master station, and the master station sends power pulses whose peak value is sufficiently higher than the data pulse for data transmission to the transmission line at predetermined intervals. In each slave station, the electric charge of the power pulse is accumulated by a diode and a capacitor to serve as driving power for the slave station, and at the end of the power pulse, both ends of the transmission path are terminated with characteristic impedance due to the reverse bias effect of the diode. 1. A data transmission method, which enables high-speed digital signal transmission, and performs data transmission by inserting data to be transmitted as data pulses between the power pulses and transmitting the data to a transmission path.