JPH0145278B2 - - Google Patents

Description

Detailed Description of the Invention The present invention connects a plurality of transmitters and receivers to a transmission line, calls an appropriate receiver from any transmitter, and controls the load dependent on the called receiver. The present invention relates to an interrupt method for a load monitoring control system that allows an emergency signal or the like to be interrupted with priority over the transmission and reception of other normal transmission signals.

FIG. 1 shows an example of a conventional load monitoring control system. This conventional example shows a control system using a power line carrier method. That is, the AC line is a power supply line to the load 4 and is also used as a control signal transmission line 1. It is assumed that the transmitter 2 monitors and controls between the first received signal 3 to the n-th receiver 3 using the control signals shown in FIG. The contents of this control signal are as follows. That is, the start signal notifies the receiver 3 of the start of the control signal, and the address data is sent to each receiver 3.
The control data is data indicating the control content transmitted from the transmitter 2 to the receiver 3, and the parity check is address data individually assigned to the transmitter 2 to the receiver 3. It is. Also, the response data is the data of the response content transmitted from the receiver 3 to the transmitter 2. Using this data, the transmitter 2 monitors the load condition connected to the receiver 3, and the end signal is the end of the control signal. shows. Of course, the above is an example of the control signal. One pit of this control signal corresponds to one cycle of the zero-crossing pulse of the AC power supply shown in FIG. 3b. In addition, the start signal, end signal, data "0" signal, and data "1" signal are also generated by dividing one period of the zero-crossing pulse in FIG. 3b into four, as shown in FIG. 3a and b. When the carrier wave shown in B in the same figure is superimposed on the AC power waveform shown in A in the middle, it is set as "1", and when it is not carried on, it is set as "0", and the start signal is "0101" and the end signal is "0110". ”,
Data 0 signal is “0100”, data 1 signal is “0111”
It is said that By allocating signals as described above, it is possible to distinguish between times when a data "0" signal is being transmitted and times when no signal is being transmitted. Let us consider the case where a control signal is transmitted from the transmitter 2 to its corresponding receiver 3 in a state in which the control signal is currently being transmitted, that is, in a busy state when the line is in use. In the system shown in Fig. 1, after the line changes from busy to non-busy, the transmitter 2 waits, for example, 16 clocks (one clock is one period of the zero-crossing pulse) as shown in Fig. 4, and then transmits the signal. Suppose you are about to start. In this system, there is a problem in that no matter how urgent a signal is to be transmitted, when the line is busy, the control signal cannot be sent at all, and even when the line is not busy, the line must wait 16 clocks. Note that a in Figure 4
b indicates the control signal of the other transmitter 2 which is currently transmitting, and b indicates the control signal of the transmitter 2 which is about to start transmitting a signal.

Next, a block diagram of the transmitter 2 of the system shown in FIG. 1 is shown in FIG. In this circuit of FIG. 5, the input switch 5 is an external operation switch and an address recognition switch for the transmitter 2, and an input section 6 latches the signal from the input switch 5. Next, the transmission data creation section 7 creates a control signal as shown in FIG. 2 using the signal from the input switch 5, and the transmission section 8 sends out the signal created by the transmission data creation section 7. When the line becomes non-busy (line open), the 16-clock standby unit 9 counts 16 clocks and outputs a 16-clock standby signal to the transmitting unit 8. On the other hand, the busy detection section 10 monitors the output of the received data reproduction section 12 to detect a busy state (line in use), and the transmission error detection section 1
1 compares the transmitted data and the received data, and if the data is incorrect, outputs a retransmission request signal. The received data reproducing unit 12 also determines the presence or absence of a carrier frequency, reproduces the received data,
The modulation/demodulation section 13 modulates and demodulates the control signal.
Furthermore, the zero-crossing detection section 14 detects zero-crossing of the AC power frequency, and the timing signal creation section 15 creates a timing signal synchronized with the zero-crossing pulse detected by the zero-crossing detection section 14.The above is an explanation of the operation of each part. It is. Although not particularly shown, the receiver 3 has almost the same circuit configuration as the transmitter 2, and has a received data reproducing section 12.
An output circuit for controlling the load 4 is added to the receiver 3, thereby allowing the receiver 3 to be operated locally.

Thus, the transmitter 2 has a circuit configuration as shown in FIG.
, the transmitter 2 is connected to an external input switch 5.
When trying to send a control signal using a trigger signal generated by the operation of the controller, first determine whether the controller is busy or not, and if it is busy, wait until it becomes non-busy and another 16 clocks have elapsed before transmitting. Start. Also, if the above determination is not busy, transmission of the control signal is started, but at this time it is determined whether or not there is a transmission error, and if a transmission error is detected, the transmission operation is immediately stopped and (16+
transmission will resume after the clock (own address number). Here, the busy detector 10 determines that the carrier frequency is busy and outputs a busy signal no matter which part of the four-divided area between zero-cross pulses the carrier frequency is located, and also outputs a busy signal when a transmission error is detected (16 + The reason why transmission is resumed after the clock (address number) is that by prioritizing address numbers, when several transmitters 2 try to start retransmission at the same time, This is to shift the timings from each other to prevent errors in signal transmission. Therefore, in this conventional example, even if the line becomes non-busy, control signals cannot be transmitted until at least 16 clocks have elapsed, and for this reason, urgent signals such as emergency signals cannot be transmitted. There was a problem that caused transmission problems.

The present invention has been provided in view of the above-mentioned points, and provides a load that enables emergency signals, etc. to interrupt a line in use, and allows urgent signals to be transmitted quickly and without any hindrance. The purpose is to provide an interrupt method for supervisory control systems.

An embodiment of the present invention will be described in detail below with reference to the drawings.
FIG. 6 shows an embodiment of the present invention. The embodiment circuit in FIG. 6 is the conventional circuit in FIG. 4 with the following circuit parts added, and is different from the conventional circuit in FIG. 4. Identical circuit parts are given the same numbers and their explanations will be omitted. That is, in the embodiment circuit of FIG. 6, the first
a one-shot multi 16, a second one-shot multi 17 that operates on the falling edge of the output of the first one-shot multi 16 and inputs its output to the transmission data creation section 7, and the first one-shot multi 16. an OR gate 18 which inputs the output of
Only when the output of the one-shot multi 17 is at L level, the output of the modulation/demodulation section 13 is transmitted to the received data reproducing section 1.
This circuit is constructed by adding an AND gate 19 for input to the circuit shown in FIG. 2 to the conventional circuit shown in FIG.

Thus, in this embodiment circuit of FIG. 6, when an input is received from the input switch 5, a busy signal is first output regardless of whether the line is used or not, and signal transmission between other transmitters and receivers is performed. It is designed to temporarily stop the line and interrupt the line. That is, in the embodiment circuit of FIG. 6, when the input switch 5 is operated, the signal is latched in the input section 6 as shown in FIG. 7a, and the output of the input section 6 is At the rising edge of the output, the first one-shot multi 16 is triggered as shown in FIG. be done. Therefore, the output of the OR gate 18 is as shown in the figure e.
This is input to the modulation/demodulation section 13. Therefore, a busy signal is applied to the transmission line 1 while the output of the first one-shot multi 16 is at the "H" level. This busy signal causes
Even if the other transceivers 2 and 3 are transmitting signals as shown in FIG. However, in the circuit of the transmitter 2 itself that generated this busy signal, the AND gate 19 does not transmit this busy signal to the received data reproducing section 12. Therefore, after the other transceivers 2 and 3 receive no busy signals, the seventh
As shown in Figure h, the signal is transmitted after the (16 + own address) clock, but this circuit uses OR gate 1.
After the 1 output reaches the "H" level, signal transmission can begin after (16 + own address) clock as shown in g in the figure. In other words, even if the line is in use, if there is an input from input switch 5, this circuit will
By forcing a busy signal onto the transmission line 1 and causing a transmission error in the other transceivers 2 and 3, signal transmission can be stopped and the control signal of the interrupt circuit can be interrupted into the line. . Note that FIG. 7d shows the output of the transmission data creation section 7.

Since the present invention is configured as described above, it is possible to interrupt the signal even when control signals are being sent and received between other transmitters and receivers, so that it is possible to interrupt signals such as emergency signals. This has the effect that urgent signals can be transmitted quickly and reliably.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of the load monitoring control system, Figure 2
The figure is a data format diagram of the same control signal as above, Figure 3a,
b is an explanatory diagram of the same operation as above; FIGS. 4a and 4b are explanatory diagrams of operation from the time when the first transmitter ends sending out the control signal until the second transmitter starts sending out the control signal; FIG. 5 is a block diagram of a conventional transmitter, FIG. 6 is a block diagram of a transmitter according to an embodiment of the present invention, and FIGS. 3 is a transmitter, 3 is a receiver, and 4 is a load.

Claims (1)

[Claims] 1. A plurality of transmitters and receivers are connected to a transmission line, the transmitter sends out a transmission signal including address data, and the receiver selected by the address data controls its dependent load,
In a load monitoring control system equipped with a transmitter configured to have a function to detect a transmission error and start retransmission after a certain period of time when this transmission error is detected, it is necessary to input an interrupt signal such as an emergency signal. On the other hand, there is a method of injecting a dummy signal onto the transmission line to cause a transmission error to other transmitters using this transmission line, and a method of injecting a dummy signal onto the transmission line to cause a transmission error. The present invention is characterized in that the transmitter is provided with a means for not capturing the signal, so that the emergency control signal is sent out while another transmitter temporarily suspends signal transmission due to a transmission error caused by the above-mentioned signal. Interrupt method for load monitoring control system.