JPH07240698A - Data communication system - Google Patents

Abstract

PURPOSE:To supply power at all times to a receiving equipment that receives data transmission and power supply by means of signals sent from a sending equipment. CONSTITUTION:A control circuit 11 always applies a drive signal S1 to an oscillation circuit 12 and selects a level of a switching signal S2 fed to a frequency variable circuit 13 to a high level or a low level depending on the content of transmission data RD1. The oscillation circuit 12 outputs a reference signal to the frequency variable circuit 13 while the control circuit 11 sends a drive signal S1. The variable frequency circuit 13 frequency-divides the reference signal into a frequency f1 when the switching signal S2 is at a high level and into a frequency f2 when the switching signal S2 is at a low level, and then the frequency-divided signal is fed to a transmission circuit 14. A transmission coil L1 of the transmission circuit 14 sends an intermittent wave signal whose frequency is f1 and a complementary signal whose frequency is f2 complementing the whole range of the intermittent part of the intermittent wave signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention transmits and receives data between a transmission side device and a reception side device and supplies operating power of the reception side device by an electromagnetic wave used for transmitting transmission data from the transmission side device. The present invention relates to a data communication method involving power transmission.

[0002]

2. Description of the Related Art For example, in a conveyor line in a factory, in a device for performing data communication between a tag attached to an article passing on the conveyor and an antenna installed to face the tag, Since the distance between the antenna and the antenna is extremely close, a data communication device that does not have a built-in battery in the tag and uses the transmission power from the antenna as the power supplied to the tag circuit by charging the capacitor There is (JP-A-62-39927)
Issue). In such a data communication device, generally, digital data is modulated into an analog signal by ASK (Amplitude Shift Keying), transmission data is constituted by an intermittent wave signal, and transmitted from an antenna which is a transmission side device. In the intermittent part of the intermittent wave signal, the reply data is transmitted from the tag which is the receiving side device.

For example, as shown in FIG. 6, the transmission data RD1 transmitted from the transmission side device is differentiated by changing the ratio of the "Hi" period in one cycle of the intermittent wave, and the reception side device is specified. When the transmission data (DATA3 in the example shown in FIG. 6) is received, the reply data TD1 is transmitted at the intermittent portion of the intermittent wave signal. Further, the reception side device demodulates the transmission data to perform half-wave rectification and uses it as a power source.

As described above, when one device for transmitting and receiving data receives power from the other and data is transmitted and received in a relatively short time, the circuit configuration is relatively large. Communication by the simple ASK method is general, and frequency shift keying (FSK: Frequency ShiftK) used when the length of data to be transmitted / received is long.
eying) is not used. This is because in the FSK system, while data is being transmitted from one device, the other device only performs a receiving operation, so the device on the power supply side receives power while transmitting data. It will be impossible to receive the supply of.

[0005]

However, in the conventional ASK communication system, there is a time during which no signal is transmitted from the transmission side device to the reception side device in the intermittent part of the transmission signal, and during this period, the reception side device is powered. In some cases, it may not be possible to receive the power supply, and it may be impossible to reliably obtain the power required for the processing in the receiving side device. It is necessary to install the device, and it is necessary to provide an oscillator circuit accordingly, which causes a problem that the device becomes large and power consumption increases. Furthermore, due to the delay at the time of rising and falling of the transmission coil in the transmission side device, the period of the intermittent wave signal forming the transmission data cannot be shortened so much in order to prevent the preceding and following data from interfering with each other. There is a problem that the data transmission speed cannot be improved and the data communication cannot be performed at high speed.

An object of the present invention is to enable a FSK from a transmitting side device.
By transmitting the transmission data by the method, it is possible to prevent the time when the power is not supplied to the receiving side device from occurring, improve the power transmission capability to the receiving side device, and all the power consumed in the receiving side device is externally supplied. It can be surely applied, the size of the device can be reduced by eliminating the need for the internal power supply and the oscillation circuit, and the influence of the delay of the rise and fall times of the transmission coil of the transmission side device can be suppressed. Another object of the present invention is to provide a data communication method capable of improving data transmission speed and reliability.

[0007]

According to a first aspect of the present invention, a transmission side device receives transmission data composed of an intermittent wave signal from a transmission side device to a reception side device, and the reception side device transmits to the transmission side device. In the data communication method in which the transmitting device transmits the reply data and the electric power is transmitted from the transmitting device to the receiving device, a complementary signal having a frequency different from the intermittent signal is transmitted over the entire range of the intermittent portion of the intermittent wave signal. It is characterized by transmitting from.

According to a second aspect of the present invention, the reply data is composed of a signal having the same frequency as the intermittent wave signal transmitted from the receiving side device while the complementary signal is being transmitted, and the transmitting side The device is characterized in that the reply data is received at a frequency obtained by combining the frequency of the complementary signal and the frequency of the signal forming the reply data.

[0009]

In the invention described in claim 1, the transmission data transmitted from the transmission side device to the reception side device covers the entire range of the intermittent wave signal of a constant cycle and the intermittent part of the intermittent wave signal. It is composed of a complementary signal having a frequency different from that of the intermittent signal. Since the frequency of the intermittent wave signal and the frequency of the complementary signal are different, the content of the data can be read by receiving the frequency of the intermittent wave signal as a signal component in the receiving side device. Further, since the complementary signal is transmitted in the intermittent portion of the intermittent wave signal, the intermittent wave signal or the complementary signal is always transmitted from the transmission side device. Therefore, the receiving device can always be supplied with electric power by the signal transmitted from the transmitting device.

In the invention described in claim 2, the receiving side device transmits the return data having the same frequency as the frequency of the intermittent wave signal transmitted from the transmitting side device. Therefore, the receiving side device can share the coil for receiving the transmission data and the coil for transmitting the reply data, and the configuration of the receiving side device can be simplified. Further, the reply data is transmitted during the transmission of the complementary signal, and the transmission side device can accurately receive the reply data by including the receiving coil that resonates at the frequency obtained by combining the frequency of the complementary signal and the frequency of the reply data.

[0011]

1 is a block diagram of an apparatus in which a data communication system according to the present invention is implemented. This device is a conveyor 10
A data carrier (tag) 2 attached to a side surface of a moving body (article) 3 that moves above, and an antenna 1 arranged at a position close to and facing the data carrier 2.
And a transmission line 4 for connecting the antenna 1 and a host controller (which is composed of a programmable controller or the like) (not shown). The antenna 1 constitutes a communication area 5 shown in the figure, and when the data carrier 2 moves into the communication area 5, its presence is detected and communication is performed with the data carrier 2.

FIG. 2 is a block diagram of an antenna and a data carrier forming the above device. Antenna 1 is
It is composed of a control circuit 11, an oscillation circuit 12, a frequency variable circuit 13, a transmission circuit 14 and a reception circuit 15.
The transmission circuit 14 and the reception circuit 15 have a transmission coil L1 and a reception coil L2, respectively,
Communication is performed by electromagnetically coupling with the transmission / reception circuit 18 of. The control circuit 11 exchanges data with a host-side device (not shown) connected via the transmission line 4 together with data transmission control and data reception control. Oscillation circuit 1
2 outputs a reference wave of a signal to be transmitted to the data carrier 2 according to the drive signal S1 supplied from the control circuit 11.

The frequency variable circuit 13 outputs the reference wave output from the oscillator circuit 12 to the frequency f ₁ and the frequency f ₂ according to the contents of the switching signal S2 supplied from the control circuit 11.
The signal is divided into. For example, a signal of frequency f ₁ is output when the switching signal S2 is at “Hi” level, and a signal of frequency f ₂ is output when it is “Lo”. In addition, the receiving circuit 15
Receiving coil L2, a frequency f ₁ and frequency f has
It resonates at the composite frequency f ₃ of ₂ . As a result, the receiving circuit 15 detects the signal of the frequency f ₁ transmitted from the data carrier 2 while the signal of the frequency f ₂ is transmitted from the transmission coil L1, as described later. This detection signal is input to the control circuit 11 as the reception data TD2.

The data carrier 2 comprises a control circuit 16, a memory 17, a transmission / reception circuit 18 and a power supply circuit 19. The control circuit 16 performs control of sending data to be transmitted to the transmission / reception circuit 18 and fetching data received by the transmission / reception circuit 18 and storing the data in the memory 17. The memory 17 is assigned a region for storing data to be transmitted to the antenna 1 and a region for storing data received from the antenna 1. The transmission / reception circuit 18 communicates with the transmission circuit 14 and the reception circuit 15 of the antenna 1 by electromagnetic coupling. The power supply circuit 19 supplies power to these elements.

The transmitting / receiving circuit 18 includes a transmitting / receiving coil L3.
And the capacitor C1, and the coil L of the antenna 1
Data communication is performed by resonantly coupling with the transmission / reception circuits 14 and 15 including 1 and L2. The coil L3 is the antenna 1
Resonate at one frequency and same frequency f ₁ which constitutes a signal transmitted from the signal of the frequency f ₁ is transmitted from the coil L3. The power supply circuit 19 includes a diode D1, a capacitor C2 and a constant voltage circuit 19a.
The diode D1 rectifies the signal current received by the transmission / reception circuit 18 of the capacitor C1 and the coil L3,
2 charges that current. The constant voltage circuit 19a converts the charging voltage of the capacitor C2 to a constant voltage to control the control circuit 1
6, output to the memory 17 and other circuits as a power supply voltage.

In this way, the resonance frequency of the coil L3 is
Since the frequency of the signal transmitted from the antenna 1 is the same as the frequency f ₁ and the frequency of the signal transmitted from the data carrier 2 is the same frequency f ₁ as the one frequency, the frequency of the reception coil in the data carrier 2 is and a transmitter coil and shared by the same coil L3, it is possible to simplify the configuration, the receiving coil L2 of the antenna 1 which resonates with a synthetic frequency f ₃ of the frequency f ₁ and frequency f _2, the data carrier 2 reply signal Can be received accurately.

The amplifier A includes a capacitor C1 and a coil L3.
The signal received by the transmission / reception circuit 18 is subjected to waveform shaping and signal demodulation and input to the control circuit 16 as reception data RD2. Further, the control circuit 16 outputs the transmission data to the FET transistor Tr1. Therefore, the received data from the amplifier A, which is a demodulation circuit, is input to the control circuit 16,
At the time of transmission, the transmission data is output from the control circuit 16 to the FET transistor Tr1, so that the transmission data is modulated by the FET transistor Tr1 and the coil L3 is received.
And it is output as an electromagnetic wave from the resonance circuit of the capacitor C1. The power supply voltage at this time is supplied from the capacitor C2. The Zener diode D2 is provided for protecting the FET transistor Tr1, rectifying and stabilizing the transmission signal.

3 and 4 are flowcharts showing the processing procedure in the antenna and data carrier. The control circuit 11 of the antenna 1 outputs the drive signal S1 output to the oscillation circuit 12 to "Hi" after the power is turned on.
Set to level (n1). As a result, the oscillator circuit 12 constantly inputs the reference wave signal to the frequency variable circuit 13 in the power-on state. This allows the antenna 1 to operate regardless of whether the data carrier 2 is within the communication area 5.
Transmission processing of transmission data is always performed from the transmission coil L1 to the communication area 15. It is also possible to arrange a photoelectric sensor on the upstream side of the antenna 1 and start the transmission processing of the transmission data after detecting that the data carrier 2 has entered the communication area 5 with this sensor.

Next, the control circuit 11 switches the switching signal S2 supplied to the frequency variable circuit 13 to the "Hi" level or the "Lo" level at a timing according to the content of the predetermined transmission data RD1 (n2 to n7). ). That is, first, the switching signal S2 is set to the "Hi" level and then (n
2) For the N-bit transmission data, it is determined for each bit whether it is "1" or "0" (n3). If it is "0", after waiting for time t1 (n4), time t2 (t2).
= T-t1), the switching signal S2 is maintained at the "Lo" level (n5, n6). In the case of "1", after waiting for the time t3 (t3> t1) (n7), the switching signal S2 is maintained at the "Lo" level during the time t4 (t4 <T-t3) (n8, n9), the presence or absence of the reply data TD1 transmitted from the data carrier 2 is determined (n10 to n12).

The control circuit 16 of the data carrier 2 controls the "Hi" of the transmission data RD1 received by the receiving circuit 18.
The level period is measured (n21 to n23), and when this period is time t3, the reply signal S3 is output to the FET transistor Tr1 at a predetermined time t5 (n24 to n23).
n27). That is, in this embodiment, the data carrier 2
Returns the reply data TD1 only when the transmission data RD1 transmitted from the antenna 1 is "1".

As a result of the above processing, as shown in FIG. 5, the antenna 1 with respect to the communication area 5 has the frequency f ₁ at the cycle T.
The intermittent wave signal is transmitted, and the complementary signal of frequency f ₂ is transmitted at the intermittent portion. Data carrier 2 enters the communication area 5, when receiving the transmission data RD1 of "1", the reply data TD at frequency f ₁ during the complementary signal of frequency f ₂ is transmitted from antennas 1
Send 1. The receiving coil L2 of the antenna 1 resonates with both the intermittent wave signal of the frequency f ₁ transmitted from the transmitting coil L1 and the complementary signal of the frequency f ₂ ,
As described above, the resonance frequency of the receiving coil L2 is the frequency f ₁
And the frequency f ₂ are combined frequency f ₃ , and when the transmission coil L ₁ receives the reply data TD ₁ of the frequency f ₁ transmitted while transmitting the complementary signal of the frequency f ₂ , the received signal The level of TD2 becomes maximum.

As is apparent in FIG. 5, the antenna 1
The intermittent wave signal of the frequency f ₁ and the complementary signal of the frequency f ₂ are alternately transmitted at all times, and the data carrier 2 can be constantly supplied with electric power while it is located in the communication area 5. Therefore, even if the processing in the data carrier 2 takes a relatively long time, the processing operation can be normally executed without requiring the internal power supply.

Further, the rise and fall times of the transmission data RD1 transmitted from the antenna 1 are not delayed by the characteristics of the transmission coil L1 and the cycle T of the intermittent wave signal constituting the transmission data RD1 is shortened. Therefore, the data length can be shortened and the speed of data communication can be increased.

In this embodiment, only the case where the reply data TD1 is transmitted from the data carrier 2 when the 1-bit transmission data RD1 transmitted from the antenna 1 is "1" has been described. The present invention can be similarly applied to the case of transmitting command data composed of bits and returning the multi-bit code data stored in the memory 17 from the data carrier 2 to the command data. . In this case, the antenna 1 transmits the command data and then transmits the data of “1” by the predetermined number of bits, thereby receiving the multi-bit code data transmitted from the data carrier 2 during this period. Can be read.

Further, the frequency of the return signal from the antenna 2 may be a frequency f ₄ which is different from any of the frequencies forming the signal transmitted from the antenna 1. In this case, the data carrier 2 is provided with a reception coil and a transmission coil separately, or a single coil for transmission and reception and a frequency for switching the resonance frequency of this coil between reception and transmission. By providing the switching circuit and setting the resonance frequency of the receiving coil L2 of the antenna 1 to the combined frequency of the frequency f ₂ and the frequency f ₄ , the above effect can be obtained.

[0026]

According to the first aspect of the present invention, a signal can be constantly transmitted from the transmission side device to the reception side device, and the reception side device can always receive power transmission. Even when performing a process that requires a relatively long time, sufficient power can be supplied, so that the receiving device can completely remove the power supply and the transmitter circuit can be eliminated, and the receiving device can be made compact. There is an advantage that can be realized. Furthermore, delays in the rise time and fall time of the transmission signal in the coil can be prevented, the time interval of the transmission data can be shortened without causing interference of preceding and following data, and the data transmission speed and reliability can be improved. There is also an advantage that can be done.

According to the second aspect of the invention, the reply data transmitted from the receiving side device can be accurately received by the transmitting side device, and the receiving coil and the transmitting coil are provided in the receiving side device. By sharing, it is not necessary to provide each separately or to provide a frequency conversion circuit, and there is also an advantage that the configuration of the receiving side device can be simplified.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an apparatus to which a data communication system of the present invention is applied.

FIG. 2 is a block diagram of the device.

FIG. 3 is a flowchart showing a process of a control unit of the device.

FIG. 4 is a flowchart showing a process of a control unit of the device.

FIG. 5 is a diagram showing a waveform of a signal in each unit of the same device.

FIG. 6 is a diagram showing signal waveforms of respective parts in a device to which a conventional data communication system is applied.

Claims (2)

[Claims] 1. A transmission side apparatus receives transmission data composed of an intermittent wave signal to a reception side apparatus, transmits reception data to the transmission side apparatus from the reception side apparatus, and receives from the transmission side apparatus. A data communication method for transmitting power to a device on the side, wherein a complementary signal having a frequency different from that of the intermittent signal is transmitted from the device on the transmitting side over the entire range of the intermittent portion of the intermittent wave signal. 2. The reply data is composed of a signal having the same frequency as the intermittent wave signal transmitted from the receiving side device while the complementary signal is being transmitted, and the transmitting side device has the frequency of the complementary signal. The data communication system according to claim 1, wherein the reply data is received at a frequency obtained by combining the frequencies of the signals forming the reply data.