JPH09107317A - Data transmission method utilizing indoor power line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the data transmission method by which an optimum transmission rate is quickly decided while keeping a high transmission efficiency. SOLUTION: A transmission means 3 and a reception means 4 generate respectively a reference timing signal based on a frequency of power supply on an indoor power distribution line and the transmission means 3 starts data transmission with a prescribed delay from the reference timing signal corresponding to a data transmission rate. Then the reception means 4 measures a delay time from the reference timing signal to the reception of data to receive the data at a data transmission rate corresponding to the delay time.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to AC100V and A
The present invention relates to a data transmission method for performing data transmission using indoor power wiring such as C200V.

[0002]

2. Description of the Related Art Data transmission is not limited to wired or wireless transmission, but sometimes it is impossible to perform data transmission due to the influence of noise in the installation environment or disturbance of the data waveform. The installer or the user needs to appropriately adjust the data transmission rate according to each environment in order to stably realize reliable data transmission. However, since it is difficult to determine whether the data transmission failure is temporary, it is often the case that the transmission speed is set low with a margin larger than the maximum data transmission speed.

In particular, in a data transmission method using indoor power wiring, carriers of a predetermined frequency are propagated on a high-voltage power supply line within the prescribed values of various radio regulations, so that ordinary signal cables and telephone lines are used. The environment is more susceptible to noise than the method using. Furthermore, since various devices such as office equipment such as printers and power equipment such as motors are connected to the power distribution line, they are exposed to a relatively noisy environment.

Therefore, when determining the data transmission rate,
In consideration of the worst case of the transmission environment, the transmission rate must be set to a low value, resulting in a decrease in transmission efficiency.

As a prior art for solving such a problem, there is JP-A-2-162924. There, a signal that indicates the transmission rate is added before the signal that should be originally sent (main signal), and the data transmission rate is changed according to the error rate, so that data transmission according to the quality of the transmission environment is efficient. Have been to.

FIG. 5 is a timing diagram showing a conventional signal transmission method. Here, an example in which data is transmitted between the master unit and the slave unit will be described. When the master unit uses the transmission rate determined as the initial value and adds the speed instruction signal to the front of the main signal to transmit as a series of signals, the slave unit receives using the transmission rate of the initial value. After this transmission is completed, the child device transmits a return signal having the same content at the same transmission rate to the parent device. The master unit compares the transmitted signal with the received signal to calculate the transmission error rate.

As a result, when the transmission error rate is higher than the specified value, the transmission rate is reduced to half and the second data transmission is performed, and the transmission error rate is calculated and evaluated. By thus evaluating the transmission error rate while changing the data transmission rate, the transmission rate at which the data transmission can be performed as efficiently and stably as possible is determined.

[0008]

However, in the conventional data transmission method, since an extra signal for instructing the data transmission rate is added, the transmission efficiency is reduced accordingly.

An object of the present invention is to provide a data transmission method capable of rapidly determining an optimum transmission rate while maintaining high transmission efficiency.

[0010]

SUMMARY OF THE INVENTION The present invention is a data transmission method for transmitting data between a transmitting means and a receiving means via an indoor power wiring, wherein the transmitting means and the receiving means are power source frequencies flowing in the indoor power wiring. A reference timing signal is generated on the basis of the reference timing signal, the transmission means delays a predetermined time from the reference timing signal in response to the data transmission rate, and starts data transmission. A data transmission method using indoor power wiring, characterized in that a delay time is measured and data is received at a data transmission rate corresponding to the delay time. According to the present invention, the reference timing signal is generated based on the power supply frequency, and the magnitude of the time delayed from the reference timing signal until the start of transmission and reception is associated with the data transmission rate. Therefore, even if there is no speed instruction signal as in the conventional case, the receiving side can recognize the transmission speed, and no extra data transmission is required, so that the data transmission efficiency is remarkably improved.

Further, the present invention is characterized in that the reference timing signal is generated in synchronization with a zero cross point of the power supply frequency. According to the present invention, a stable reference timing signal can be easily generated by detecting and utilizing the zero-cross point of the power supply frequency.

[0012]

1 is a block diagram showing a transmission circuit to which a data transmission method according to the present invention is applied. The indoor power wiring PL is, for example, AC100V or AC20.
Electric power of 0 V or the like is supplied, and various devices are connected to each other through an outlet or the like and supplied with electric power. Among various devices, a device such as a printer or a computer that performs data transmission is similarly supplied with power from the indoor power wiring PL through a power cable, and in the present invention, the power cable is also used as a signal cable.

FIG. 1 illustrates a configuration in which two data transmission devices are connected to the indoor power wiring PL,
One operates as a master P and the other operates as a slave C. The parent device P and the child device C of the data transmission device are microprocessor units (MPs) that perform signal processing according to a predetermined program.
U) 1, zero-cross detection means 2 for detecting a zero-cross point of the power supply frequency, transmission means 3 for transmitting transmission data on a carrier, and reception means 4 for receiving signals transmitted from other devices. To be done. Here, an example will be described in which transmission data is transmitted from the transmission unit 3 of the parent device P and received by the reception unit 4 of the child device C, but the same applies to transmission in the opposite direction.

FIG. 2 is a timing diagram showing a data transmission method according to the present invention. FIG. 3 is a flowchart showing the operation on the data transmitting side. FIG. 4 is a flowchart showing the operation on the data receiving side.

First, the generation of the reference timing signal will be described. 50Hz or 60 for the indoor power wiring PL
A voltage having a power supply frequency of Hz is applied, and there is a zero-cross point that becomes 0 V only twice in one cycle. The zero-cross detection means 2 of the parent device P and the child device C includes a comparator that compares a predetermined threshold value with the power supply voltage, and generates a pulse synchronized with the zero-cross point. If a window comparator that uses two-level thresholds of +5 V and -5 V, for example, is used as the comparator, a pulse centered at the zero-cross point is obtained as shown in FIG. Thus, the reference timing signal synchronized with the zero cross point of the power supply frequency is generated.

Next, the procedure for transmitting the data string will be described. As shown in FIG. 3, the transmitting means 3 of the parent device P waits until it detects a zero-cross point in step a1, and when it detects the zero-cross point due to the rise of the reference timing signal, the process proceeds to step a2. The data transmission rate is, for example, 1200 bps (the number of bits per second),
2400bps, 4800bps, 9600bps 4
The delay time from the rise of the reference timing signal corresponding to each transmission rate can be set so that the stages can be switched, and the following (Table 1) is shown.

[0017]

[Table 1]

In step a2, it is judged whether or not the data transmission speed to be executed is 1200 bps,
If it is 1200 bps, the process proceeds to step a5 and the data transmission rate of the transmitting means 3 of the parent device P is 1200 bps.
Is set for 1 msec from the rise of the reference timing signal in step a6, and data transmission is started in step a13. The delay time of 1 msec is 0.00
It is a numerical value appropriately selected within the range of to 1.99 msec, and is not limited to 1 msec as long as it is within this range.

If the data transmission rate is not 1200 bps, it is determined in step a3 whether it is 2400 bps. If it is 2400 bps, the process proceeds to step a7 and the data transmission rate of the transmitting means 3 of the master P is set to 240.
It is set to 0 bps, waits for 3 msec from the rise of the reference timing signal in step a8, and starts data transmission in step a13. The delay time of 3 msec is also a numerical value appropriately selected within the range of 2.00 to 3.99 msec.

If the data transmission rate is not 2400 bps, it is determined in step a4 whether it is 4800 bps. If it is 4800 bps, the process proceeds to step 9 and the data transmission rate of the transmitting means 3 of the master P is set to 4800 bps.
It is set to bps, waits 5 msec from the rise of the reference timing signal in step a10, and starts data transmission in step a13. The delay time of 5 msec is a numerical value appropriately selected within the range of 4.00 to 5.99 msec.

If the data transmission rate is not 4800 bps, it is determined that it is the last 9600 bps, the process proceeds to step 11, the data transmission rate of the transmitting means 3 of the parent device P is set to 9600 bps, and the reference timing is set in step a12. Wait 7 msec after the signal rises, then step a1
At 3, the data transmission is started. The delay time of 7 msec is a numerical value appropriately selected within the range of 6.00 to 7.99 msec.

The data transmission in step a13 continues until it is judged in step a14 that the data string transmission is completed.
Based on the preset data transmission rate, the data transmission is started after waiting for a predetermined delay time corresponding to the transmission rate from the rise of the reference timing signal.

Next, the procedure for receiving the data string will be described. As shown in FIG. 4, the receiving means 4 of the slave C waits until the zero cross point is detected in step b1, and when the zero cross point is detected by the rise of the reference timing signal, the process proceeds to step b2. In step b2, first, the transmission speed of the receiving means 4 is set to 1200 bps.
And wait for 2.0 msec at step b3.

In the next step b4, it is judged whether or not the data transmission to the receiving means 4 is started, and 0.00-1.99 mse from the rising edge of the reference timing signal.
If data transmission has started within the range of c, step b
The process proceeds to 14 and data reception is started at 1200 bps. If data transmission has not started within 2.0 msec from the rise of the reference timing signal, the transmission speed of the receiving means 4 is set to 2400 bps in step b5, and step b
At 6, wait another 2.0 msec.

In the next step b7, it is judged whether or not the data transmission to the receiving means 4 is started, and if the reference timing signal rises, 2.00 to 3.99 mse.
If data transmission has started within the range of c, step b
Then, the process proceeds to 14 to start data reception at 2400 bps. If data transmission has not started within 4.0 msec from the rise of the reference timing signal, the transmission speed of the receiving means 4 is set to 4800 bps in step b8, and step b
At 9, wait another 2.0 msec.

At the next step b10, the receiving means 4
It is determined whether or not the data transmission to the terminal has started, and if 4.000 to 5.99 ms from the rising edge of the reference timing signal.
If the data transmission has started within the range of ec, the process proceeds to step b14 and data reception is started at 4800 bps. If the data transmission has not started within 6.0 msec from the rise of the reference timing signal, the transmission speed of the receiving means 4 is set to 9600 bps in step b11, and the process waits for another 2.0 msec in step b12.

At the next step b13, the receiving means 4
It is determined whether or not the data transmission to the terminal has started, and if it is 6.00 to 7.99 ms from the rising edge of the reference timing signal.
If data transmission has started within the range of ec, the process proceeds to step b14 and data reception is started at 9600 bps. If data transmission has not started within 8.0 msec from the rise of the reference timing signal, the process returns to step b1 and waits until the next zero cross point.

The data reception in step b14 is continued until it is judged in step b15 that the data string reception is completed.
In this way, based on the delay time from the rise of the reference timing signal to the start of data transmission, the data transmission speed of the handset C is determined with reference to Table 1, and data reception is started.

FIG. 2 shows an example in which transmission and reception of a data string are alternately performed between the master P and the slave C,
The data transmission rate starts from 2400 bps as an initial value. First, the transmitting means 3 of the parent device P starts transmitting the main signal 3 msec after the rise of the reference timing signal. Then, the reception unit 4 of the child device C has a delay time of 3
The data transmission rate is determined to be 2400b by determining that it is msec.
Set to ps and receive the main signal from the master P. After the transmission of this data string is completed, the transmitting means 3 of the child device C transmits a return signal of the same content to the parent device P at the same transmission speed. The parent device P compares the transmitted signal with the received signal to calculate the transmission error rate.

As a result, when the transmission error rate is larger than the specified value, it is determined that the transmission environment is insufficient, and the transmission rate is reduced from 2400 bps to 1200 bps to perform the second data transmission. At that time, the transmission means 3 of the parent device P starts transmitting the main signal 1 msec after the rise of the reference timing signal. Then, the reception means 4 of the slave C determines that the delay time is 1 msec, resets the data transmission rate to 1200 bps, and receives the main signal from the master P. After the transmission of this data string is completed, the transmission means 3 of the child device C
Transmits a return signal having the same content at the same transmission speed to the parent device P. The parent device P compares the transmitted signal with the received signal to calculate the transmission error rate.

As a result, if the transmission error rate satisfies the specified value, it is determined that the transmission environment is sufficient, the subsequent data transmission rate is set to 1200 bps, and the data transmission is continued.

On the other hand, when the transmission error rate satisfies the specified value at the data transmission rate of 2400 bps, 4800 bps or 9600 bps is aimed at for more efficient transmission.
The same alternating transmission is performed by increasing the transmission speed such as. By thus evaluating the transmission error rate while changing the data transmission rate, the transmission rate at which the data transmission can be performed as efficiently and stably as possible is determined.

[0033]

As described in detail above, according to the present invention, the reference timing signal is generated based on the power supply frequency, and the delay time from the reference timing signal until the start of transmission and reception and the data transmission rate are increased. Are associated with. Therefore, even if there is no speed instruction signal as in the conventional case, the receiving side can recognize the transmission speed, and no extra data transmission is required, so that the data transmission efficiency is remarkably improved.

Further, a stable reference timing signal can be easily generated by detecting and utilizing the zero crossing point of the power supply frequency.

In this way, it is possible to realize a data transmission method capable of quickly determining the optimum transmission rate while maintaining high transmission efficiency.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a transmission circuit to which a data transmission method according to the present invention is applied.

FIG. 2 is a timing diagram showing a data transmission method according to the present invention.

FIG. 3 is a flowchart showing an operation on the data transmission side.

FIG. 4 is a flowchart showing an operation on the data receiving side.

FIG. 5 is a timing diagram showing a conventional signal transmission method.

[Explanation of symbols]

 1 Microprocessor Unit 2 Zero Cross Detection Means 3 Transmission Means 4 Reception Means

Claims (2)

[Claims] 1. A data transmission method for transmitting data between a transmitting means and a receiving means via an indoor power wiring, wherein the transmitting means and the receiving means respectively provide a reference timing signal based on a power supply frequency flowing through the indoor power wiring. Generate,
The transmitting means delays a predetermined time from the reference timing signal in response to the data transmission speed to start data transmission, and the receiving means measures the delay time from the reference timing signal to data reception and responds to the delay time. A data transmission method using indoor power wiring, characterized in that data reception is performed at a data transmission rate of 2. The data transmission method using indoor power wiring according to claim 1, wherein the reference timing signal is generated in synchronization with a zero cross point of a power supply frequency.