JPS63304739A - Power phase synchronizing data transmission system - Google Patents

Abstract

PURPOSE:To eliminate the need for a synchronizing signal line between transmission and reception by allowing an electronic device at transmission/reception side of a data to apply transmission/reception of the data synchronously with a synchronizing pulse generated from each power phase detection means in sending the data via a transmission line. CONSTITUTION:Power phase detection means 41-4m generating a synchronizing pulse detecting a phase point common to an electronic device in the system based on the AC waveform of a power supply and designating a phase point are provided respectively to electronic devices 21-2m. Then the electronic devices are interconnected by a single transmission line 50, and in case of the data transmission via the transmission line 50, the electronic devices 21-2m at the data transmission or reception side apply the data transmission or reception synchronously with the synchronizing pulse sent from the power phase detection means 41-4m. Thus, the transmission and reception is ensured via the single transmission line 50 by using the synchronizing pulse generated from the power phase detection means 41-4m provided corresponding to the electronic devices 21-2m without the provision of a synchronizing signal line between the transmission side electronic device and the reception side electronic device.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a synchronous data transmission method within a system consisting of a plurality of electronic devices, and is suitable when the plurality of electronic devices are powered by the same AC power source. Regarding data transmission methods.

[Conventional technology]

As is well known, data transmission methods can be roughly divided into asynchronous methods and synchronous methods. Generally speaking, the former allows data transmission without providing a synchronous signal line, but the transmission and reception control tends to be complicated. Although the latter method is easy to control transmission and reception, it requires the provision of a synchronizing signal line, which is cumbersome. The sixth @ conceptually shows how to perform the latter synchronous data transmission between a pair of electronic devices.

A pair of electronic devices 101 and 102 shown in FIG. 6 are communication interfaces 101a each having transmission and reception capabilities.

102a, e.g. unidirectional transmission line 111.11
0 and 2 electronic devices ff1o1 are interconnected via
．． 102 each operate under a unique clock pulse;
Since the communication interfaces 101a and 102a also operate in synchronization with this unique clock pulse, the synchronization signal lines 111s and 111a are used to transmit this clock pulse or the related transmission synchronization pulse SP to the other party.
12s is provided between both side devices. When transmitting data from one electronic device to the other, the electronic device on the transmitting side sends data in the form of a pulse train to the transmission line, and also sends a synchronization pulse SP to the electronic device on the receiving side via the synchronization signal line. The electronic device on the receiving side receives and receives the pulse train constituting the data in synchronization with this synchronization pulse SP.

[Problem that the invention seeks to solve]

As mentioned above, in the synchronous data transmission system, it is necessary to transmit a data pulse train from the transmitting side to the receiving side and at the same time transmit a synchronization pulse unique to the transmitting side to the receiving side. In addition to transmission lines for commands and commands, synchronization signal lines for transmitting synchronization pulses must be provided, and in the above example, a total of four lines are provided between both electronic devices. Of course, from an economic point of view, it is desirable that the number of lines for such interconnection be as small as possible.
Therefore, although the transmission line can be a bidirectional transmission line 110 as shown by the ill line in FIG. Since this is desirable, at least three lines must be drawn between the transmitter and the receiver.In this way, the synchronous data transmission method has the advantage that it is easy to control transmission and reception on both the transmitter and receiver sides, and the communication interface and software in the electronic device can be simplified. However, it has the drawback of requiring a synchronization signal line between transmitting and receiving.

It is an object of the present invention to solve the problems of the synchronous data transmission system and to provide a data transmission system that does not require the provision of a synchronous signal line between transmitting and receiving.

[Means for solving problems]

According to the present invention, this object or problem is achieved by providing a synchronous data transmission method for each electronic device in a system consisting of a plurality of electronic devices that are powered by the same AC power source and interconnected by transmission lines as described above. A power supply phase detection means for detecting a phase point common to electronic devices in the system based on the AC waveform of the power supply and generating a synchronization pulse to specify the phase point is provided for each, and a single They are coupled by a transmission line, and when transmitting data via the transmission line, the electronic device on the data transmitting or receiving side transmits or receives data in synchronization with the synchronization pulses generated by the respective power supply phase detection means. This is achieved by

[Effect]

The above-mentioned AC power supply primarily needs to provide a power supply voltage of the same frequency to all electronic devices in the system, but the power supply phase detection means provided for each electronic device detects a common phase point from the AC waveform. In order to detect detects a common phase point in the system based on the AC waveform of the power supply with the same phase, but in this case, the zero crossing point, maximum, and peak point of the small edge are detected from the AC waveform itself or its rectified waveform. By doing so, the power frequency or its second
A synchronized pulse train with double or quadruple repetition frequency can be generated.

In order to transmit data between two specific electronic devices in the system according to the present invention, a synchronizing signal line is not particularly provided between the two electronic devices, and the two devices are coupled by a single data transmission line. In the transmitting side electronic device, in synchronization with the jtJl conversion pulse generated from the corresponding power supply phase detection means,
The am interface basically puts a data pulse train on the transmission line at a rate of 1 bit per 1 synchronization pulse,
In the receiving electronic device, this data pulse train is received from the transmission line in synchronization with the synchronization pulse from the power supply phase detection means on the receiving side. Since the phase of the synchronized pulse train generated by the transmitting-side ta phase detection means is common to the synchronized pulse train generated by the transmitting-side ta phase detection means, and therefore both synchronized pulse trains are substantially the same pulse train, the transmitting-side electronic device and the receiving-side electronic device Even if the two electronic devices are not connected by a synchronizing signal line, transmission and reception can be carried out between the two electronic devices without any trouble, just as in the case where both electronic devices are connected by a synchronizing signal line.

The above-mentioned configuration and operation of the present invention solve the above-mentioned intended problem, but as can be seen from the above description, the electronic devices in the system to which the method of the present invention can be applied are powered by the same AC power supply with almost the same phase. Therefore, the method of the present invention is not very suitable for data transmission between electronic devices distributed over a very wide area, but is not suitable for data transmission between electronic devices that are located within the same factory, facility, or area. It is suitable for applications in which a simple one-chip microcomputer, for example, is incorporated as an electronic device in a device or weighing device, and data is transmitted between such devices or between it and a central electronic device, and the data transmission is performed in a synchronous manner. By doing so, each communication interface can be simplified and synchronization signal lines between electronic devices can be omitted, making it possible to construct a data transmission system with low equipment costs and transmission line installation costs.Another problem with the method of the present invention As mentioned above, the frequency of the synchronization pulse is four times the commercial frequency, that is, up to about 200 to 24 Qtlz, and the transmission rate is basically 1 pint per synchronization pulse, so the transmission speed is not very fast. That's true. However, if the application is data transmission of measured values or weighing values as mentioned above, this level is often sufficient for practical purposes, and if higher-speed data transmission is required, the frequency of the synchronization pulse can be easily changed. It is also possible to increase the phase synchronization to about 10 to 20 times using a frequency multiplier without disturbing the phase synchronization state. These advantageous embodiments of the inventive system are described in the following sections.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings. 1st
1 and 2 show an example of the configuration of a data transmission system implementing the power supply phase synchronized data transmission system according to the present invention.

In FIG. 1, m nodes of this data transmission system are indicated by symbols 11 to l-, and in this example, each of these nodes is coupled via a common data transmission line 50. Each node 11-1- is provided with electronic devices 21-21, respectively, and these electronic devices are connected to a data transmission line 50 via communication interfaces 21a-2-a, respectively. All of these electronic devices 21-2- are supplied with power from a common power source 2, which is taken from a power distribution transformer 2a receiving the voltage of the arrangement line 1. The nodes 11 to Im shown in FIG. 10 and data transmission lines 51 to 5, respectively.
connected in a dendritic manner by m. The central electronic device placed in node 10 collects the measured values and weighing values generated in nodes 11 to 1 through data transmission, and then connects it to an external system via another communication & 1160, for example, a telephone line. be done. 2-) is an example of connecting nodes 11-1- through a loop-shaped data transmission 1% I20, one of these nodes or another node 1- as shown being connected to a central electronic device. is located there, and is similarly connected to an external system via a communication line 60. Of course, in this case as well, nodes 11 to 1
- and 1n are all powered by the same AC power supply.

Returning to FIG. 1, at each node 11-1-, for example, the AC voltage of the power supply 2 is received via transformers lla to 1s+a, and the secondary voltage thereof is converted into a pulsating DC voltage by, for example, the illustrated full-wave rectifiers 11b to 1mb. . This rectified voltage is converted to DC-D via an RC smoothing circuit 11c"1mc as usual.
It is applied to constant voltage power supplies such as C converters lid to 1d, and the DC constant voltage therefrom is applied to electronic devices 21 to 2m. Power supply phase detection means 41 to 4 in this embodiment
The voltage source is capacitor-coupled to the output side of the rectifiers 11b to 1mb, and receives the pulsating alternating current voltage in the rectified voltage. The reason why the rectifiers 11b to 1+*b are full-wave rectifiers is that even if the phase of AC voltage intake into the transformers lla to 1ma differs from node to node, the phase point detected by the power supply phase detection means is This is to prevent such things from happening. For example, as described above, the power supply phase detection means 41 to 4- detect the zero crossing points and peak points of the pulsating AC voltage waveform in the rectified voltage input thereto as phase points common to the system, and perform synchronization synchronized with the phase points. Any device that emits a synchronizing pulse SP may be used, and as can be easily seen, the synchronizing pulse train SP generated by this is 1 in this embodiment.
It has the same wave number four times the is frequency. However, in this embodiment, frequency multipliers 41a to dma are provided at the subsequent stage to increase this frequency and increase the data transmission speed, and thereby the frequency of the synchronization pulse SP is further increased, for example, by eight times. It will be done. Therefore, in this embodiment, the communication interface 21a of the electronic devices 21 to 2m+
The synchronization pulse SP applied at ~2 ma has a frequency of, for example, 1.9 kHz, assuming that the power supply frequency is 60 Hz.

FIG. 3 shows an example of the configuration of an electronic device, and in this figure, the electronic device is designated by the reference numeral 20. This electron'A position 20
consists of, for example, a one-chip microcomputer 30, a communication interface 20a, and a data generator 2Gb, and if the data generator I 20b of these is, for example, a measuring device or weighing device as described above, it is actually a one-chip microcomputer 30. and a communication interface 20a are incorporated into these devices. The one-chip microcomputer 30 has, for example, an 8-pin internal operation, and although it is small, it has a CPU 31. ROM32. RAM
33. Bus 34°! 10 ports) 35, 36, etc., and the data generator ffi 2
0 communication interface 20a that stores the data in the RAM 33 and exchanges the data to be transmitted with the communication interface 20a via the I10 port 36.
In principle, the elP functions as a shift register, and the RAM of the one-chip microcomputer 30
The 8-bit data from 33 is read in bit parallel through the I10 port, port 36 or latch, and then the synchronization pulse SP is output in series to the transmission line 50 as a kind of shift pulse, or vice versa. It is something.

The synchronization pulse SP is therefore connected to the communication interface 20a.
The communication interface 20a provided to the I10 port 36 and the I10 port 36 may be directly connected to the bus 34 without going through the I10 port 36, as the case may be.

Figure 4 shows an example of data transmission.
1) shows the waveform of the synchronization pulse SP, and the waveform of the transmission signal TS is shown in the figure (bl shows an example of the waveform of the transmission signal TS). The transmission signal S is emitted for each focus and is shown in the figure.
Each bit BO-83 has a meaning of 1.1, 0.1. Figure 5 shows an example of the structure of a message for data transmission in the method of the present invention.
An example of the data message DM is shown in the same figure (bl).It is advantageous to configure these messages as fixed-length messages in order to simplify the communication interface. ) The command message CM shown in ) specifies the data transmission destination and commands the data transmission from there.For example, as shown in the figure, the command message CM is the synchronization code SC, start bit SR.
, command C port, etc. For example, the synchronization code SC consists of about 20 bits of simple 1 repeated, and this is followed by a start pinpoint S8 which is 1 bit O. Therefore, on the receiving side, l is a predetermined bit. It is only necessary to receive the next command CC on the condition that it is continuous for a long time and the next 1 bit becomes O.The length of this command CC is usually 5 to 8 bytes, and it is necessary to receive the next command CC. For example, the first byte is a specific code to distinguish that it is a command, and the last byte is an error detection code. Same figure To)
In the example above, the data message DM also includes a synchronization code SC and a start bit SR, and the synchronization code SC has a length of, for example, 25 bits to make it easier to distinguish it from the command message. be done. In this example, the data DT
follows, and its length is, for example, 32 per data message.
It is about a byte, and the last byte is used as an error detection code. In addition, confirmation messages,
It would be better to use a non-confirmation message as usual, but it is omitted because it becomes complicated. In either case, in the case of the present invention method, in order to convert the communication interface configuration and data transmission software in the one-chip microcomputer into an hourglass,
As mentioned above, it is desirable that each message be a relatively short message with a fixed length and a simple code structure, and that the type of message should have a small winding force.

In addition to the embodiments described above, the method of the present invention can be implemented in various modified states.For example, as a power supply phase detection means, in addition to finding the zero cross point or peak point in an AC waveform, it can also be implemented using known techniques. A predetermined phase point can be detected. Although it is desirable for the structure and type of the message to be simple as described above, it is possible to improve the reliability of transmission by appropriately adding conventional techniques known as transmission techniques. Regarding the transmission speed, although it is most reliable to use one bit per synchronization pulse as in the example, it is also possible to use a PLL circuit to transfer internal clock pulses whose phase is synchronized to the synchronization pulses within the communication interface. For example, if you devised a way to generate 1 pulse per synchronization pulse,
It is also possible to improve the transmission speed to bytes.

Although the method of the present invention essentially allows data transmission between any pair of electronic devices in the system, if the main purpose is to collect measured values or weighing values, It is advisable to use the device as a central electronic device and to centrally collect data on it, for example by polling.
A single data message from multiple electronic devices can be transmitted to the central electronic device using one data message as described above, and a command message is no longer necessary, and even if a command message is used, one data message from one It is possible to construct a system that can complete one data transmission within one second.

〔Effect of the invention〕

According to the present invention, as a synchronous data transmission method in a system consisting of a plurality of electronic devices that are powered by the same AC power source and connected to each other by transmission lines, the system transmits data based on the AC waveform of the power source for each electronic device. A power supply phase detection means is provided for detecting a phase point common to electronic devices in the system and generating a synchronization pulse that specifies the phase point, and each electronic device is connected by a single transmission line, and the transmission line When transmitting data via the electronic device, the electronic device on the transmitting or receiving side transmits or receives data in synchronization with the synchronization pulse generated by the respective power supply phase detection means, so that the electronic device on the transmitting side and the electronic device on the receiving side Transmission and reception can be performed via a single transmission line using synchronization pulses generated by the power phase detection means provided corresponding to each electronic device, without having to provide a synchronization signal line between the device and the device as in the past. This can be done reliably. As described above, according to the present invention, the system can be simplified by omitting the synchronous signal line compared to the conventional synchronous data transmission method, and transmission and reception control is easier than in the conventional asynchronous data transmission method.・You can enjoy the advantages of the synchronous data transmission method as is.The data transmission method according to the present invention uses the principle of synchronizing transmission and reception with the power supply phase, so power is supplied to electronic devices included in the system from the same power source. However, for data transmission between electronic devices in factories, facilities, and specific areas that can meet this requirement, the present invention reduces equipment costs and transmission line wiring costs compared to conventional methods. It can provide a practical method that requires much less.

The method of the present invention, which has the above advantages, is particularly suitable for applications where data generated by measuring devices and weighing devices is collected and managed in one place, and its value will be demonstrated as the optimal method for this type of application in the future. It is expected that

[Brief explanation of drawings]

1 to 5 relate to the present invention; FIG. 1 is a block circuit diagram showing a configuration example of a multiple electronic device system implementing the power phase synchronized data transmission system according to the present invention; FIG. 3 is a block circuit diagram showing an example of the configuration of each electronic device in the system, and FIG. 4 is a waveform diagram of synchronization pulses and transmission signals. FIG. 5 is a diagram showing the structure of some messages used during data transmission. Figure 6 is a schematic configuration diagram of data transmission between two electronic devices using the conventional synchronous data transmission method.In Figure 0, 1: distribution line, 2: AC power supply common to the system, 2a: distribution transformer , 11-1: Node on intra-system data transmission, 11a
~1sa+) Lance, llb ~1mb: Rectifier,
11c to 1-c: smoothing circuit, lid to lad: constant voltage power supply, 20 to 2a: electronic device, 20a to 2ma: communication interface, 20b: data generation bag fi, 30: one-chip microcomputer, 3t: CPU, 32
:ROM, 33j RAM. 34: Bus, 35.36: I/O boat, 41-4
-: Power supply phase detection means, 41a to 4■a: Frequency multiplier, 50 to 5m: Data transmission line, 60: Communication line or telephone line, BO to Bl transmission (each bit of the number, CC: command, CCs: First byte of command, CH: command message, DM: data message, FIT: data, SB start bit, SC: synchronization code, SP: synchronization pulse,
τS: Transmission signal, Fig. 2

Claims (1)

[Claims] A synchronous data transmission method within a system consisting of multiple electronic devices powered by the same AC power source and connected to each other by transmission lines, in which each electronic device transmits electronic data within the system based on the AC waveform of the power source. A power supply phase detection means for detecting a common phase point in the devices and generating a synchronization pulse for specifying the phase point is provided, the electronic devices are each connected by a single transmission line, and data is transmitted via the transmission line. This is a power phase synchronized data transmission system in which electronic devices on the data transmitting or receiving side transmit or receive data in synchronization with synchronization pulses emitted by their respective power source phase detection means.