JPS6143758B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a communication control system for a remote scanner that controls an input switch that sequentially takes out a plurality of analog inputs in a predetermined order.

For example, in a two-wire remote temperature monitoring and recording device that monitors and collects temperatures at multiple points, an input switch is used that outputs analog signals indicating temperatures obtained at multiple detection points in a predetermined order. This input switch is controlled by scanning a large number of analog inputs when a remote scanner including this input switch receives a command from the central station.
This is done by converting each analog input into a digital signal and sending it to the central office. This method has the advantage that only two signal paths are required between the central office and each remote scanner, reducing wiring costs, but the scanning speed depends on the response speed of the input switch and the A/D conversion. If you try to increase the scanning speed, it is necessary to use complicated and expensive elements for these input switchers and A/D converters, and reliability is limited. There will also be a decline in

An object of the present invention is to control the input switch so that even if the input switch is scanned and the resulting analog signal is digitized at low speed, the system as a whole has the same effect as high-speed scanning. The objective is to provide a method to do so.

Next, an embodiment of the present invention will be described with reference to the drawings. In Figure 1, the symbols 1 _-1 , 1 _-2 ,
1 _-3 ………1 The remote scanner indicated by _-o is 2
It is connected to a central station 3 by a wire line 2, and the central station 3 connects each REET scanner 1 _-1 to _{1 -o.}
Each time each remote scanner receives a call from the central office 3, it digitizes the analog input signal obtained by the scanning operation of the input switch, and sends the digitized signal to the central office. It has the function of sending out to the station.

As shown in FIG. 2, each remote scanner _1-1 to 1- _o has a transceiver 11 that communicates with the central station 3 through a line 2, and the calling signal sent from the central station 3 is After being received by the transceiver 11, it is supplied to the station number determiner 12. The station number determiner 12 compares the station number of the received calling signal with its own station number preset in the station number setter 13, and when the two match, the control circuit 1
4, and at the same time sends a transmission start signal to the central station 3 via the transceiver 11.

When the control circuit 14 receives the start signal from the station number determiner 12, it sends the station number code of the remote scanner to the gate circuit 16, and reads the contents of the address counter 15 indicating the channel number taken in by the input switch 19. and already input switch 1
The digital signal data of the channel corresponding to the channel number is sent from the gate circuit 16 to the transmitter/receiver 11, and the digital signal data of the channel corresponding to the channel number is sent from the gate circuit 16 to the transmitter/receiver 11, and the digital signal data of the channel corresponding to the channel number is sent from the gate circuit 16 to the transmitter/receiver 11. station number, channel address number,
Each signal of the measurement data of the channel number is sent from the line 2 to the central station 3. This operation will be explained later.

When the sending of the digital signal is completed, the control circuit 14 sends a carry to the address counter 15,
As a result, the address counter 15 is
Send the address code 1up to 8. This becomes a drive signal for inputting the data of the next channel number of the input switch 19. In other words, this decoder 18
is for supplying a drive signal for causing the input switching device 19 to perform a scanning operation according to the address code given from the address counter 15, and if the input switching circuit 19 uses a relay, , which is a combination of a decoder circuit and a relay drive circuit.

The input switching circuit 19 scans the input terminals of a large number of channels, each of which is supplied with analog signal data, according to a drive signal designated by a channel (address) from the decoder 18, and applies the scanned signal to a selected input terminal. It has a function of supplying an analog measurement signal to the A/D converter 17. The A/D converter 17 has a function of converting the analog signal sent from the input switch 19 into a digital signal and temporarily storing it, and is preferably of an integral type. . When the station number determiner 12 detects a calling signal from the central office 3, the gate circuit 11 transfers the already stored digital signal data for one channel in response to a control signal from the control circuit 14.
Send it out on 6th. In other words, each remote scanner
_-1 to 1 _-o transmit data for one channel and perform a scanning operation each time the station number signal is received.

In other words, in the remote scanner according to the method of the present invention, after sending out one channel's worth of digital signal data, the scanning operation is performed to take in the input signal of the next channel of the input switch 19, and It spontaneously performs the digital conversion operation of analog signal data, stores the analog input data for the next channel in the form of digital signal data, and stores this stored data every time there is a call from the central office 3. It performs the operation of sending the stored digital signal data to the central office.

For example, a remote scanner (1 shown in Figure 1)
_-1 to 1 _-o ) for each remote scanner 1
The operation will be described with reference to FIG. 3 assuming that the number of input terminals (number of channels) of the input switch ₁₉ from _-1 to 1 -o is m.

In FIG. 3, when the remote scanner with the station number 1 receives the station number signal, it transmits the measurement data of the mth channel of the input switch 19, which has been stored in advance, to the central station 3 together with the station number and channel number. Then, the input switch 19 takes in the input signal of the first channel next to the m-th channel, performs AD conversion, and waits for the next station number signal to arrive. During this time, the central station 3 has station numbers 2, 3,...
... n remote scanners 1 _-1 to 1 _-o , and perform the same operation as station number 1. Data is collected one by one from each remote scanner 1 _-1 to 1 _-o . Then, when the remote scanner with station number 1 receives the station number signal again,
The input signal of the first channel, which has been A-D converted and stored, is sent to the central station 3, and then the input signal of the second channel is sent to the central station 3.
The input signal of the channel is taken in by the input switch 19, converted from A to D, and waits for receiving the station number signal again. In this way, m ×
The central station 3 receives n pieces of data, and repeats the data updating operation in the same manner.

In this way, the conversion operation for one input signal of a certain remote scanner 1 _-1 to 1 _-o can be performed by the central station converting it to several other remote scanners 1 _-1 to 1 _-o .
Since it is sufficient to terminate the communication while communicating with the user, there is sufficient time. Therefore, if n remote scanners 1 _-1 to 1 _-o are used, then
The scanning operation of the input switch 19 and the A/D converter 17 of This means that conversion operations can be performed. This means that even though they operate at a slower speed, this does not slow down the data transmission. Therefore, the reliability is improved by scanning the input switching circuit 19 at a reasonable speed, and the economical efficiency is improved by being able to use an inexpensive A/D converter 17 with a slow conversion speed. This can be achieved without any deterioration.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a communication system to which a communication control system for a remote scanner according to an embodiment of the present invention is applied, FIG. 2 is a block diagram showing one of the remote scanners, and FIG. It is a graph which shows the signal waveform of each part of a figure. 1 _-1 to 1 _-o ...Remote scanner, 2...Line, 3...Central station, 11...Transmitter/receiver, 12...
Station number determiner, 14...control circuit, 15...address counter, 16...gate circuit, 17...A/
D converter, 19...input switch.

Claims (1)

[Claims] 1 Each time a plurality of remote scanners are sequentially called from the central station, the 1
The digital signal data for each channel is sent to the central station, and after this sending is completed, the input switching circuit is operated for scanning to take out the analog signal data applied to the input terminal of the next channel. supplying the analog signal data thus obtained to the A/D converter to convert it into a digital signal, and controlling the digital signal data to be stored in preparation for the next call;
The central station communicates with at least one remote scanner other than the remote scanner by the paging, and within the communication period, the remote scanner retrieves the analog data and converts it into a digital signal. A communication control method for a remote scanner, characterized in that the operation of storing information in an A/D converter is also terminated.