JP2024115692A - Multiple Devices - Google Patents

Abstract

To provide a multiple device that easily and accurately synchronizes and aligns sensor detection timing without the need for complex compensation processing of software.SOLUTION: A multiple device 10 has a plurality of devices including a higher-level device (host device H), a lower-level device (sensor device 4), and one or more intermediate devices (sensor devices 1 to 3) located between the higher-level device and the lower-level device. Each of the devices is connected in series by a communication line to enable data transmission and reception between the devices. The multiple device sends data acquisition request commands that control timing for acquiring a predetermined data signal SDA to respective devices, in a manner of sending them earlier to devices located more away from the higher-level device in association with each device, and sends all the data acquisition request commands for intermediate devices sequentially, before the data acquisition request command reaches the lower-level device.SELECTED DRAWING: Figure 1

Description

This invention relates to a multiplex device.

Patent document 1 discloses an invention related to a multiple sensor in which multiple sensor units are daisy-chained. Patent document 1 claims that communication can be established between adjacent sensor units or between a host and a sensor unit, and that communication quality can be maintained appropriately.

JP 2019-50502 A JP 2012-238341 A JP 2004-88208 A JP 2016-66278 A Japanese Patent Application Publication No. 10-13394

Patent document 1 does not mention synchronization of data acquisition. On the other hand, technology for achieving synchronization using a common synchronization signal line, as described in patent documents 2 to 4, is widely known (see Figure 1 of patent document 2, Figure 3 of patent document 3, Figure 1 of patent document 4, etc.).

However, there was a problem in that the number of devices that could be connected and the distance between devices were limited by the driving force of the common synchronization signal line.

On the other hand, in Patent Document 5, the type and length of the transmission line are input to the device to determine the propagation delay time due to the transmission line, and the amount of correction is calculated from the propagation delay time.

However, since the propagation delay time differs depending on the device, correcting the propagation delay time for a large number of devices requires complex correction processing, which places a large burden on the software.

The present invention aims to provide a multiple device that can be synchronized easily and accurately without the need for dedicated synchronization signals or complex software correction processing.

The multiple device of the present invention has a plurality of devices including a higher-level device, a lower-level device, and one or more intermediate devices located between the higher-level device and the lower-level device, and each device is connected in series by a communication line to enable data transmission and reception between each device. The multiple device is characterized in that a data acquisition request command that controls the timing of acquiring specific data at each device is associated with each device, and the data acquisition request command for the device that is farther away from the higher-level device is transmitted first, and all of the data acquisition request commands for the intermediate devices are transmitted in sequence before the data acquisition request command reaches the lower-level device.

In the present invention, it is preferable that, after transmitting the data acquisition request command to a lower-level device between devices, the next data acquisition request command is subsequently transmitted to the lower-level device.

In the present invention, it is preferable that the higher-level device is a host device, and the intermediate device and the lower-level device are sensor devices that detect wind.

The present invention makes it possible to realize a multiple device that can easily and accurately synchronize and align sensor detection timing without requiring dedicated synchronization signals or complex software correction processing.

FIG. 1 is a schematic diagram of a multiple device according to the present embodiment. FIG. 2 is a conceptual diagram for explaining a problem in command transmission of a multiple device in a comparative example. FIG. 3 shows an example of command transmission from multiple devices according to this embodiment. FIG. 4 is an example of a communication block diagram of the multiple devices according to the present embodiment. FIG. 5 is an example of a circuit diagram of a sensor.

One embodiment of the present invention (hereinafter, abbreviated as "embodiment") will be described in detail below. Note that the present invention is not limited to the following embodiment, and can be practiced in various modifications within the scope of the gist of the invention.

FIG. 1 is a schematic diagram of a multiple device 10 according to the present embodiment.
1, a multiple device 10 according to the present embodiment is configured to include a host device H and a plurality of sensor devices 1 to 4. In this specification, the host device H and the sensor devices 1 to 4 may be referred to as "devices" without distinction. Furthermore, the host device H may be referred to as the "upper device", the sensor device 4 as the "lower device", and the sensor devices 1 to 3 as the "intermediate device". Furthermore, a "lower device" refers to a device that is closer to the "lower device" among adjacent devices.

As shown in FIG. 1, each device is shown with a signal line L1 for transmitting a data signal (SDA) and a signal line L2 for transmitting a clock signal (SCL) separately, but these signal lines L1 and L2 can be combined to form a communication line 5, and each device is connected in series by the communication line 5.

The host device H is a microcomputer that controls data transfer to each of the sensor devices 1 to 4, and refers to the device that acts as the master in communication. For example, the host device H is a personal computer, a server, a router, etc. Also, the sensor devices 1 to 4 are microcomputers that control sensors, LEDs, etc., and refer to the device that acts as the slave in communication.

In this embodiment, for example, physical quantity data, specifically, flow rate data, can be acquired in each sensor device 1 to 4, and particularly in this embodiment, a multiple device 10 capable of acquiring wind speed data can be provided.
In this embodiment, the devices are connected in series via a communication line 5, enabling data transmission and reception between the devices.

The timing for acquiring sensor data in each of the sensor devices 1 to 4 is when the data acquisition request command (sensor data acquisition trigger command) sent from the host device H is received. In this embodiment, the data acquisition request commands received by each of the sensor devices 1 to 4 are controlled so that they are received at approximately the same timing, improving the problem of time lags in data acquisition.

Below, we will explain command transmission, but first use Figure 2 to explain a comparative example in which the timing of data acquisition request commands is shifted for each sensor device. Note that in Figures 2 and 3, to simplify the explanation, only host device H, sensor device 1, and sensor device 2 are illustrated and explained. The vertical direction in Figures 2 and 3 indicates a time series, with time progressing from top to bottom.

As shown in FIG. 2, a data acquisition request command S1 is sent from the host device H to the sensor device 1. Note that in FIG. 2 and FIG. 3, the upper column of the box display indicates the type of command, the lower left column indicates the sender, and the lower right column indicates the receiver.

As shown in FIG. 2, the data acquisition request command S1 is a command from the host device H to all sensor devices. Therefore, as shown in FIG. 2, when the sensor device 1 receives the data acquisition request command S1 from the host device H, the sensor device 1 detects the specified data at that timing and transmits the data acquisition request command S1 from the sensor device 1 to the sensor device 2.

Then, as shown in FIG. 2, upon receiving a data acquisition request command S1 from sensor device 1, sensor device 2 performs a predetermined data detection with a delay from the timing of data acquisition by sensor device 1.

In addition, when sensor device 1 and sensor device 2 have completed data detection, they send data acquisition completion commands S2 and S3 to host device H.

As such, in the comparative example of FIG. 2, the data acquisition request command S1 sent from the host device H to the sensor devices 1 and 2 is a command to all sensor devices, and communication is carried out in a so-called bucket brigade manner, so the sensor device closer to the host device H that receives the data acquisition request command S1 first will perform data detection earlier, resulting in a time lag in data detection.

This kind of time lag in data detection also occurs in the configuration using the common synchronization signal line shown in the patent document. That is, commands for sensor devices connected far from the host device arrive later than for sensor devices connected close to the host device, so the data acquisition timing does not match in each sensor device, and the longer the common synchronization signal line, the greater the timing lag becomes, making it impossible for each sensor device to acquire sensor data at the same time or to illuminate its LED at the same time, thereby enabling the sensor functions to be performed at the same time.

Therefore, in this embodiment, in order to alleviate the problem that the timing of data acquisition is delayed as the sensor device is farther away from the host device H, resulting in a time lag in data acquisition, the transfer control of the data acquisition request command has been improved as follows.

That is, in this embodiment, a data acquisition request command is associated with each device. In this embodiment, the data acquisition request command S4 shown in FIG. 3 is associated with the data acquisition timing of the sensor device 2, and the data acquisition request command S5 is associated with the data acquisition timing of the sensor device 1. Therefore, the sensor device 2 executes data acquisition at the timing of receiving the data acquisition request command S4, and the sensor device 1 executes data acquisition at the timing of receiving the data acquisition request command S5.

Then, as shown in FIG. 3, the data acquisition request command for the sensor device farthest from the host device H is sent first. In the case of sensor device 1 and sensor device 2 shown in FIG. 3, sensor device 2 is farther away from the host device H than sensor device 1, so data acquisition request command S4 for sensor device 2 is sent first.

That is, as shown in FIG. 3, the host device H sends a data acquisition request command S4 to the sensor device 1, and the sensor device 1 further transfers the data acquisition request command S4 to the sensor device 2.

At this time, immediately after the data acquisition request command S4 is transferred from sensor device 1 to sensor device 2, a data acquisition request command S5 for sensor device 1 is sent from host device H to sensor device 1.

In this way, after the host device H transmits the data acquisition request command S4 to the adjacent sensor device 1, the host device H subsequently transmits the next data acquisition request command S5 to the adjacent sensor device 1. At this time, the host device H can transmit the data acquisition request command S5 immediately after receiving an Ack signal indicating that the sensor device 1 has received the data acquisition request command S4.

By controlling the transfer of the data acquisition request command as described above, as shown in FIG. 3, the timing at which sensor device 2 receives data acquisition request command S4 and the timing at which sensor device 1 receives data acquisition request command S5 can be made almost the same. This makes it possible to reduce the time lag between data detection by sensor device 1 and data detection by sensor device 2 to almost zero, or at least to a smaller value than in the past.

As shown in FIG. 3, sensor device 1 and sensor device 2 send data acquisition completion commands S6 and S7 to host device H. Then, host device H processes the sensor detection signals of sensor device 1 and sensor device 2 obtained at the same time.

As described above, in terms of FIG. 1, host device H issues a data acquisition request command to sensor device 4, which is the farthest connected device. Then, when sensor device 1 next to host device H receives the data acquisition request command, it immediately issues a data acquisition request command to sensor device 3, which is the second farthest from host device H. Each device transfers each data acquisition request command up to the sensor device associated with the data acquisition request command, and just as the data acquisition request command for sensor device 4 reaches the farthest sensor device 4, the data acquisition request command for each sensor device also reaches each of sensor devices 1 to 3. In this way, the timing of the data acquisition request commands reaching each sensor device can be made approximately the same, making it possible to reduce the time lag in sensor detection compared to conventional methods.

In this embodiment, the time lag in sensor detection can be reduced regardless of the number of connected sensor devices. Although not limited to this, proper synchronization can be achieved even if the number of sensor devices ranges from several hundred to several thousand.

By increasing the number of connected sensor devices, the distance between the host device H and the farthest sensor device becomes longer, but in this embodiment, the devices are connected by communication lines 5, and the system is capable of sending and receiving data between the devices. Therefore, even if the total communication distance is longer than in a system using a conventional common synchronization signal, proper synchronization can be achieved by controlling the transfer of the data acquisition request command in this embodiment.

Figure 4 is a communication block diagram of the multiple devices of this embodiment. As shown in Figure 4, the host device H is configured to have an upper communication control unit 12, a lower communication control unit 13, and a processor 14. In addition, each of the sensor devices 1 to 4 is configured to have an upper communication control unit 15, a lower communication control unit 16, a processor 17, and a sensor function unit 18.

In this way, each host device H and each sensor device 1 to 4 has two communication control units: upper communication control units 12, 15 and lower communication control units 13, 16.

The upper communication control unit 12 of the host device H is connected to an information control device 30 such as a PC, and the lower communication control unit 13 of the host device H controls transmission and reception with the sensor device 1 located on the lower side.

Similarly, the lower communication control unit 16 of each of the sensor devices 1 to 4 is connected to the upper communication control unit 15 of the sensor device located on the lower side, and controls transmission and reception between each of the sensor devices.

The processor 14 provided in the host device H controls commands from the information control device 30 and performs various processes on data from the sensor devices 1 to 4.

The processor 17 provided in each sensor device 1 to 4 performs various processes, such as writing data from the sensor output to a memory for sending to the host and processing based on commands from the host device H.

The sensor function unit 18 provided in each of the sensor devices 1 to 4 shown in FIG. 4 is a function unit that acquires data. For example, if it is a wind sensor that detects wind, it is configured as follows.

FIG. 5 is an example of a circuit diagram of the sensor function unit.
As shown in Fig. 5, the sensor function unit configures a bridge circuit 27 with a flow rate detection resistive element 25, a temperature compensation resistive element 26, and resistors 28 and 29. As shown in Fig. 5, the flow rate detection resistive element 25 and the resistor 28 configure a first series circuit 19, and the temperature compensation resistive element 26 and the resistor 29 configure a second series circuit 20. The first series circuit 19 and the second series circuit 20 are connected in parallel to configure the bridge circuit 27.

As shown in FIG. 5, the output 21 of the first series circuit 19 and the output 22 of the second series circuit 20 are each connected to a differential amplifier (amplifier) 23. A feedback circuit 24 including the differential amplifier 23 is connected to the bridge circuit 27. The feedback circuit 24 includes a transistor (not shown) and the like.

The resistors 28 and 29 have a smaller temperature coefficient of resistance (TCR) than the flow rate detection resistor 25 and the temperature compensation resistor 26. The flow rate detection resistor 25 has a predetermined resistance Rs1 in a heated state controlled to be higher than a predetermined ambient temperature by a predetermined value, and the temperature compensation resistor 26 is controlled to have a predetermined resistance Rs2 at the ambient temperature. The resistance Rs1 is smaller than the resistance Rs2. The resistor 28 constituting the first series circuit 19 with the flow rate detection resistor 25 is, for example, a fixed resistor having a resistance R1 similar to the resistance Rs1 of the flow rate detection resistor 25. The resistor 29 constituting the second series circuit 20 with the temperature compensation resistor 26 is, for example, a fixed resistor having a resistance R2 similar to the resistance Rs2 of the temperature compensation resistor 26.

When wind acts on the flow rate detection resistor element 25, the temperature of the flow rate detection resistor element 25, which is a heat generating resistor, drops, causing the potential of the output section 21 of the first series circuit 19 to which the flow rate detection resistor element 25 is connected to fluctuate. This causes a differential output to be obtained by the differential amplifier 23. Then, the feedback circuit 24 applies a drive voltage to the flow rate detection resistor element 25 based on the differential output. Then, based on the change in the voltage required to heat the flow rate detection resistor element 25, the wind speed can be converted and output by a microcomputer, which will be described later.

As described above, in this embodiment, the communication control units in the host device H and the sensor devices 1 to 4 are divided into an upper communication control unit and a lower communication control unit, which allows the host device H and the sensor devices 1 to 4 to be daisy-chained, making it possible to transmit commands and transmit and receive data only between adjacent devices. This allows communication control to be performed in the following ways: (1) data acquisition request commands are associated with each device; (2) data acquisition request commands for devices that are further away from the upper device are sent first; and (3) all data acquisition request commands for intermediate devices are sent sequentially before the data acquisition request command reaches the lower device. This allows proper synchronization even if the number of connected devices increases, and sensor detection can be performed at approximately the same time.

The present invention can provide a multiple device that is particularly suitable for performing sensor detection at the same time. The multiple device of the present invention is, for example, a multiple device that detects wind, and can be used both indoors and outdoors. The multiple device can be used, for example, in air conditioning equipment, illumination, and for experiments and analysis.

1-4: Sensor device 5: Communication line 10: Multiple device 12, 15: Upper communication control unit 13, 16: Lower communication control unit 14, 17: Processor 18: Sensor function unit 19: First series circuit 20: Second series circuit 21, 22: Output unit 23: Differential amplifier 24: Feedback circuit 25: Flow rate detection resistance element 26: Temperature compensation resistance element 27: Bridge circuit 28, 29: Resistor 30: Information control device H: Host device L1, L2: Signal lines S1, S4, S5: Data acquisition request command S2, S3, S6, S7: Data acquisition completion command

Claims (3)

A multiple device having a plurality of devices including an upper device, a lower device, and one or more intermediate devices located between the upper device and the lower device, the devices being connected in series by communication lines to enable data transmission and reception between the devices,
A multi-connected device characterized in that a data acquisition request command that controls the timing of acquiring specified data is associated with each device, and the data acquisition request command is sent to a device that is farther from the upper device first, and all of the data acquisition request commands are sent to the intermediate devices in sequence before the data acquisition request command reaches the lower device. The multi-connected device according to claim 1, characterized in that, after transmitting the data acquisition request command to a lower device between the devices, the next data acquisition request command is transmitted to the lower device. 3. The multi-connection device according to claim 1, wherein the upper device is a host device, and the intermediate device and the lower device are sensor devices that detect wind.

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