JPH02161846A - Remote monitor equipment - Google Patents

Abstract

PURPOSE:To permit a master device to confirm the collision of monitor request signals occurring on a signal line by securing such a constitution where each terminal equipment transmits a monitor request signal to the master device when a device to be monitored has a state change and the master device transmits a signal to the signal line to show the start of a monitoring action in response to the monitor request signal. CONSTITUTION:Each of terminal equipments B1-BN sends a monitor request signal to a master device A when one of devices C1-CN to be monitored has a state change. Thus the device A sends a signal to a signal line W to show the start of a monitoring action in response to the received request signal. Thus the application of a single signal is possible as a monitor request signal of each terminal equipment. Then the device A can confirm these request signals even though they collide with each other on the line W. Furthermore the period of time when the transmitted signals serving as the noises are superposed on each other even in a power transmission mode since the transmission of signals is carried out only in case the device to be monitored has a change.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention provides a method for transmitting and receiving information between a base unit and a plurality of terminal units via a common signal line, and monitoring the status of monitored equipment connected to the terminal unit. The present invention relates to a remote monitoring device for monitoring by the parent device.

[Prior Art and Problems to be Solved by the Invention] Various devices have been proposed for connecting a base device and a terminal device with a signal line to transmit signals.
Publication No. 84307 states that when each terminal device is provided with a clock device and the clock devices are activated all at once in response to a command from the base device, the transmission times from the terminal devices to the center are set so that they do not overlap with each other. This eliminates the need for the base unit to poll each terminal separately. Since this device allocates the usage time of the signal line to each terminal, there is no risk of the signals from each terminal colliding. Because the number of terminals used was allotted, the number of terminals could not be increased.

Furthermore, Japanese Patent Application Laid-open No. 56-7549 discloses a device that transmits signals when the signal line is idle during communication between terminal devices, and this device also prevents collisions of signals from each terminal device. However, it requires a separate logical control line to support this non-collision operation, making it unsuitable for using commercial power lines as signal lines.

Furthermore, Japanese Patent Application Laid-Open No. 48-91488 discloses that the operating states of a plurality of monitored points are periodically stored temporarily in a predetermined order, and the operating state signal of the next period at the same address as the already stored operating state signal is stored. An operating state change detecting device is shown in which only when there is a change between the two addresses, the main memory stores the address where the change occurred. However, this device is for the case where the base unit and the terminal unit are provided in one-to-one correspondence.
This technique is difficult to apply to devices that transmit data between a base unit and multiple terminals.

Furthermore, Japanese Patent Publication No. 49-32512 discloses a signal transmission device that transmits signals when there is a change in status, but this device also has a one-to-one correspondence between the base unit and the terminal device. This is also difficult to apply to a device that transmits data between a base unit and a plurality of terminal units.

This invention was made to solve the above problems, and even if there is a collision of signals on a common signal line, this invention can be confirmed on the base unit, and the power line transmission using the power line as the signal line To provide a remote control device capable of shortening the time during which transmission signals causing noise are superimposed even when the above is adopted, and also capable of connecting many terminal devices to a base device.

[Means to solve the problem]

The present invention provides a remote monitoring device in which a base unit and a plurality of terminals transmit and receive data via a common signal line, and the base unit monitors the status of a monitored device connected to the terminal unit. The device sends a monitoring request signal to the base device when a state change occurs in the monitored device connected to the terminal device, and the base device starts monitoring after receiving the monitoring request signal from the terminal device. After receiving the signal indicating that the monitored device has started monitoring, the terminal device sends a signal indicating the monitoring start to the signal line, and after receiving the signal indicating the start of monitoring, sends the signal back to the base device during the time period corresponding to its own address. The master device is characterized in that it detects the address of the terminal device in which the status of the monitored device has changed based on this return signal.

[For production]

In this invention, when each terminal device sends a monitoring request signal to the base unit when a state change occurs in the monitored device, the base unit responds by sending a signal indicating start of monitoring to the signal line. Therefore, a single signal can be used as the terminal device's monitoring request signal, and even if this monitoring request signal collides with the signal line, this signal can be confirmed by the base device.

Further, in the present invention, since transmission is performed only when a change occurs in the monitored device, even when power transmission is employed, the time during which the transmission signal causing noise is superimposed can be shortened.

Furthermore, in the present invention, since the terminal device whose status of the monitored device has changed returns a signal in the time period corresponding to its own address, it is possible to connect many terminal devices to the base device. Can be done.

〔Example〕

FIG. 1 is a block diagram showing the overall configuration of an embodiment of the present invention. In the figure, base unit A and terminal units B1 to BN are connected by a common signal line W, and these terminal units B1 to BN are connected by a common signal line W.
~BN are connected to monitored devices C1 to CN, respectively.

Figure 2 is a blower diagram showing the detailed configuration of terminal B.
In particular, it employs power line transport.

Here, a microcomputer 2 is connected to the signal line W via an input/output interface 1. A basic clock circuit 3 for driving the microcomputer 2, an address setting circuit 4 for setting the address of the terminal, and a monitored device C are connected to the microcomputer 2. Further, a pulse signal generator 8 is provided which detects the zero-crossing phase of the signal line W and generates a pulse, and its output pulse is applied to the microcomputer 2. Furthermore, the output of this Norculus signal generator 8 is transmitted to a first human power source, a microcombi, -
An AND circuit 5 is provided whose second input is a signal obtained by inverting the output of the output terminal 2 with an inverter 6. Further, a counter 7 is provided which counts the pulses output from the AND circuit 5 and is cleared by the output of the microcomputer 2, and the microcomputer 2 executes data processing based on this counted value.

The actual operation configured as described above will be explained below.

First, unless the status of any of the monitored devices CC is changed to N (7), the terminals B1 to BN will not output a monitoring scan request signal.

Next, in order to detect the status of the monitored devices C1-co on the base device A side, when the base device A sequentially outputs a monitoring scanning request signal, the terminal devices B1-BN receive the monitored device C1-co based on the signal indicating the start of monitoring. Signals indicating the status of the monitoring devices 01 to CN, that is, the monitored data, are sent back to the base unit A.

Figure 3 shows the signal format showing the operation in this case.
Base device A transmits a start signal indicating the start of monitoring and an address signal including a monitoring designation signal, and terminal devices B1 to BN corresponding to this address signal transmit status signals of monitored devices 01 to CN connected to it, that is, Sends the monitoring device data to base unit A.

Next, if the status of only one of the monitored devices Ct-CN changes, the terminal to which the monitored device whose status has changed is connected to the signal line W of the base unit A. A monitoring request signal indicating a request for monitoring activity is transmitted. and,
When base unit A receives this signal, it sends a signal indicating start of monitoring to the signal line. This signal is detected by each terminal device B1 to BN, but only the terminal device whose monitoring device data has changed waits for a time corresponding to its own address setting value and transmits the monitoring device data. Base device A receives this.

Next, we will explain the operation when the status of multiple monitored devices 61 to CN changes almost simultaneously.
The case of two terminals will be explained.

When the states of the monitored devices connected to the #n terminal and the #n+2 terminal change almost simultaneously, the #n terminal and the #n+2 terminal each indicate a request for the monitoring activity of the base unit A on the signal line W. Sends a monitoring designation signal. In this case, #n
Both the terminal device and the #n+2 terminal device use the same monitoring request signal. Then, when base unit A receives this signal,
Sends a signal indicating start of monitoring to the signal line. This signal is
Each of the terminals 81 to BN detects a change in the monitoring device data, and the terminal device waits for a time corresponding to its own address setting value and transmits the monitoring device data.

Such transmission and reception operations will be explained in detail using FIGS. 2 and 5.

First, the voltage of the commercial power line used as the signal line W changes as shown in FIG. 5(a). The pulse signal generator 8 detects this zero-crossing point of the commercial power supply voltage and
The zero-cross pulse shown in Figure (1)) is generated. In this state, the gate of the AND circuit 5 is closed by the output of the microcomputer 2, and the CL terminal of the counter 7 is in the rHJ clear state.

Next, if the monitored devices Cn"n+2 connected to terminal #n and terminal #o+2 change their states almost simultaneously, #n terminal The microcomputer 2 constituting the device and the #n+2 terminal device, via the input/output interface,
generate a monitoring request signal at about the same time. In response, base unit A receives these signals as shown in FIG. 5(0), and further responds to this by indicating a monitoring start as shown in FIG. 5(I). Sends the signal to the signal line.

Next, when a signal indicating the start of monitoring is sent from base unit A,
This signal is taken into the microcomputer 2 via the input/output interface 1 17 in the terminals 81 to BN, respectively. At this time, the microcomputers 2 of the #n and #n+2 terminals whose status has changed in the monitored equipment change the level of the terminal CL of the counter 7 to rI(
At the same time as changing the input level of the inverter 6 from rHJ to rLJ, opening the AND circuit 5 and applying the zero cross pulse of the pulse signal generator 8 to the CK terminal of the counter 7. . Therefore, the counter 7 of the #n terminal device and the #n+2 terminal device counts as shown in FIG. 5(g) and <j), and the counted number is as shown in FIG. 5(h) and (k). Changes to

Next, the microcomputers 2 of the #n terminal and #n+2 terminal determine whether the count value of the counter 7 matches the setting value of the address setting circuit 4, respectively, and
The n terminal detects this match. At this stage, the microcomputer 2 transmits the monitoring device data of the monitored device C to the parent device A via the human output interface 1, as shown in FIG. 5(1). During this data transmission,
The microcomputer 2 of the #n+2 terminal device connects the signal line W
detects that there is a signal at
Stops counting operation.

Next, when the data transmission of #n terminal device is completed, #n+2
The microcomputer 2 of the terminal device changes the input of the inverter 6 from rHJ to rLJ again.

Then, the count value of the counter 7 is determined by the address setting circuit 4.
As shown in Fig. 5 (1), when the setting value of
The monitoring device data of the monitored device C is transmitted to the base device A via the input/output interface 1.

Therefore, as shown in FIG. 5 (+n), the base unit A
After receiving the monitoring device data of the terminal device, the monitoring device data of the #n+2 terminal device is received. In this case, the detection of the zero-crossing phase of the commercial power line is done extremely quickly, so
Even for the final #N terminal, the waiting time is extremely short. In addition, in case of base unit A, if the monitoring operation is ended when there is no transmission signal for the time corresponding to the #N terminal, the time required for - times of monitoring operations can be reduced compared to the conventional device. can be significantly shortened.

FIG. 4 is a signal format showing these operations.

In this case, when the start signal and monitoring designation signal indicating the start of monitoring are sent from base unit A, the #n terminal whose monitoring device data has changed waits for the time corresponding to its own address setting value. Send monitoring equipment data. Also,
The #n+2 terminal device waits and transmits the monitoring device data until the total time during which no transmission signal exists, excluding the time when the #n terminal device transmits the monitoring device data, matches its own address setting value. .

Thus, according to this embodiment, when each terminal device sends a monitoring request signal to the base unit when a state change occurs in the monitored device, the base unit responds by sending a signal indicating start of monitoring to the signal line. Since the configuration is such that a single signal can be used as the monitoring request signal of the terminal device, even if this monitoring request signal collides with the signal line, it can be confirmed by the base device.

Further, in this embodiment, since transmission is performed only when a change occurs in the monitored equipment, the time during which the transmission signal is superimposed as noise on the commercial power line can be shortened.

Furthermore, in this embodiment, since a terminal device whose status of the monitored device has changed returns a signal during the time period corresponding to its own address, it is possible to connect many terminal devices to the base device. Can be done.

In addition, in the above embodiment, a case was explained in which a commercial power supply line was used as a signal line, but when a dedicated signal line is used as a signal line, an oscillator that generates pulses at a predetermined period can be used as a pulse signal generator. By using , the same operation as described above can be performed.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, each terminal device that transmits and receives data to and from the base device via a common signal line detects when a change in status has occurred in the monitored device connected to this terminal device. When a monitoring request signal is sent to the base unit, and after receiving the monitoring request signal from the terminal unit, the base unit sends a signal indicating start of monitoring to the signal line, and when there is a change in the status of the monitored device. After receiving a signal indicating the start of monitoring, the terminal device sends a signal back to the base device during the time period corresponding to its own address, and the base device responds to this return by checking the status of the monitored device based on No. 3. Since the AT1NOS of the terminal device that has changed is detected, there is no possibility that there will be a collision of signals on the common signal line.
In addition to being able to check the signal on the base unit, it also uses power line transport (even if the transmission signal is superimposed as noise, it can shorten the time that the transmission signal is superimposed on the base unit). This has the effect of allowing terminal devices to be connected.

~BN ...terminal device,

Claims (1)

[Claims] In a remote monitoring device in which a parent device and a plurality of terminal devices transmit and receive data via a common signal line, and the parent device monitors the status of a monitored device connected to the terminal device, the terminal device When a state change occurs in the monitored device connected to the terminal device, a monitoring request signal is sent to the base unit, and after receiving the monitoring request signal from the terminal unit, the base unit sends a signal indicating the start of monitoring. After receiving a signal indicating the start of monitoring, the terminal device sends a signal to the main device and sends a signal to the main device, and after receiving a signal indicating the start of monitoring, it sends a signal back to the main device during the time period corresponding to its own address. A remote monitoring device is characterized in that, based on this return signal, the address of a terminal device whose status of the monitored device has changed is detected.