JPH01317100A - Monitor - Google Patents

Abstract

PURPOSE:To reduce the number of cables and equipment number and to improve noise immunity and transmission speed by devising circuits from a measuring section till a storage circuit so as to be independent of an arithmetic processing circuit, rewriting data automonously to the sender side and reading the data required from the storage circuit to the arithmetic processing circuit. CONSTITUTION:An address corresponding to a storage circuit 8 of a reception section is added to a data measured by a plant by an address generating circuit 3. Then the data is sent automatically from the transmission section as a serial signal via a P/S conversion circuit 4 periodically, and the signal from the transmission section is stored in a location designated by the address via an SP conversion circuit 7 in the storage circuit 8 of the reception section. Moreover, the data required from the storage circuit 8 is read independently of the transmission by the arithmetic processing circuit 10 and monitor and control are applied through the arithmetic processing. Thus, the number of cables and equipments is saved and noise immunity and data transmission speed are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an improvement in a monitoring device that measures, monitors and controls process variables such as pressure and temperature, and radiation levels in a plant.

(Prior Art) In recent years, for the purpose of control and safety monitoring, monitoring devices have been widely used in plants such as power generation plants to measure, monitor, and control process quantities such as pressure and temperature, as well as radiation levels. ing. This type of monitoring device measures process quantities and radiation levels in a plant located in a remote location using multiple measurement units including radiation detectors, voltage/current measurement circuits, temperature sensors, pressure gauges, etc. The data obtained is transmitted to a central monitoring room using a predetermined transmission method for centralized monitoring and control.

In this case, data transmission methods are broadly classified into analog transmission methods and digital transmission methods. The analog transmission method transmits data such as measurement signals as analog quantities such as voltage values and current values. The advantage of this analog transmission method is that the data transmission speed is high, but the disadvantages are that it is difficult to send a large amount of data with one set of transmission lines, which increases the number of cables and devices, and that the analog signal By routing data over long distances, the accuracy of transmitted data tends to decrease and is vulnerable to noise. On the other hand, digital transmission methods can sequentially switch multiple pieces of data and transmit them over a single set of transmission lines, and have the advantage of being resistant to noise because they send signals that have already been digitally encoded. The data density per unit time is inevitably lower than that of analog transmission methods, and data transmission takes time due to the procedure for sending and receiving data, serial/parallel conversion, and the time required to transfer data to and from the arithmetic processing circuit. Difficult to respond.

By the way, some monitoring systems in plants require high-speed response in order to perform alarm output and plant control. For example, when the pressure in some tanks in a chemical plant increases, it is necessary to open the pressure relief valve immediately.

Also, when the output of a nuclear power plant suddenly increases,
It is necessary to prohibit the withdrawal of control rods or shut down the reactor. The disadvantages of the analog signal transmission method conventionally used in these locations are that it requires a large number of cables and devices, and is susceptible to noise.In order to improve performance, a digital transmission method is needed. In particular, it is necessary to reduce the number of cables by using serial transmission lines.

However, conventional digital transmission methods require the use of arithmetic processing devices at sites with poor environmental conditions, so there have been concerns about the reliability of the devices. Further, even when the arithmetic processing device is not used on site, it is difficult to improve the data transmission speed using a polling method or the like in which data is requested from the monitoring device side. On the other hand, a method has been proposed in which a new arithmetic processing unit dedicated to transmission is installed to reduce the load on the main arithmetic processing unit and increase speed.
There are problems in that the programs and circuits become extremely complex, which not only reduces reliability but also increases the size of the device.

(Problems to be Solved by the Invention) As described above, in conventional monitoring devices, if an analog transmission method is adopted as a data transmission method, the number of cables and
Not only does it require a large number of devices, but it is also susceptible to noise, and if a digital transmission method is used, the data transmission speed is slow, making high-speed response impossible.

An object of the present invention is to provide a highly reliable monitoring device that can reduce the number of cables and devices, improve noise resistance, and improve data transmission speed to achieve high-speed response. It is in.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the monitoring device according to the present invention includes a plurality of measurement units 1 for measuring process quantities and radiation levels, as shown in FIG. , a switching circuit 2 that inputs a plurality of data output from the measuring section 1, sequentially switches and selects them, and outputs them as transmission data; and a receiving section data storage corresponding to each data selected and output from the switching circuit 2. An address generation circuit 3 that generates a location address, a parallel/serial conversion circuit 4 that converts a plurality of parallel digital codes, which are a combination of data and addresses from the switching circuit 2, into a serial digital code and transmits the serial digital code, and an address generation circuit 4. A transmitting unit includes an automatic transmitting circuit 5 which generates a timing signal to the circuit 3 and a transmitting command to the parallel/serial converter circuit 4 at regular intervals. A serial/parallel conversion circuit 7 receives a serial digital code, converts it into a parallel digital code consisting of an address and data, and outputs it, and an address of the parallel digital code output from the serial/parallel conversion circuit 7. A memory circuit 8 that writes and stores data in a location specified by , a timing circuit 9 that creates a write signal for the memory circuit 8 based on a signal received by the serial/parallel conversion circuit 7, and It is configured to include a receiving section including an arithmetic processing circuit 10 that reads data, performs arithmetic processing, and monitors and controls alarm output and the like.

(Function) In the monitoring device of the present invention, a plurality of measurement units 1 measure process amounts and radiation levels in a transmitting unit installed in a plant remote from a place where monitoring and control is performed, and these multiple data are The data is input to the switching circuit 2, sequentially switched and selected by a timing signal periodically generated from the automatic transmission circuit 5, and input to the parallel/serial conversion circuit 4 as transmission data. Further, the parallel/serial conversion circuit 4 receives the address of the receiving section data storage location from the address generation circuit 3 for each selection of data. Then, in the parallel/serial conversion circuit 4, the data and address, which are parallel digital codes, are converted into serial digital codes, and the data is sequentially transmitted in accordance with a transmission command periodically generated from the automatic transmission circuit 5. .

On the other hand, the serial digital code from the transmitter is transmitted through a serial transmission line 6 and input to a serial/parallel converter circuit 7 of a receiver installed at a place where monitoring and control is performed. As a result, in the serial/parallel conversion circuit 7, a serial digital code is converted into a parallel digital code, contrary to the transmission section. The received signal is then divided into data and address, and in response to a write signal from the timing circuit 9, the data is stored at the location specified by the address. In this case, since the transmitting section periodically sends each data by the automatic transmitting circuit 5 regardless of the operation of the receiving section,
The data in the memory circuit 8 is updated to the latest value at the cycle of the data transmitted by the transmitter.

Furthermore, in the arithmetic processing circuit 10, the latest measurement data can be obtained simply by reading out the necessary data from the storage circuit 8, and by arithmetic processing, judgment and output of this data, monitoring and control of alarm output etc. is performed. .

Therefore, in the monitoring device of the present invention, the measuring unit 1 to the storage circuit 8 are completely independent of the arithmetic processing circuit 10, and since the transmitting side voluntarily rewrites data, handshakes such as data requests, etc. Eliminates time loss due to In addition, since the arithmetic processing circuit 10 can obtain the latest measurement data simply by reading the necessary data from the storage circuit 8, the waiting time when collecting data is minimized, and the response time of software for monitoring and control is reduced. It becomes possible to improve the performance. Furthermore, traditionally, depending on the type of data collection,
The collection time varies due to variations in the time until transmission, and it was necessary to secure the maximum time as the data collection time during software design.In contrast, in the present invention, data is read from the memory circuit 8 in a fixed time. Because it is done,
There is no need for a margin in data collection time, making it possible to improve response speed.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 2 is a block diagram showing an example of the configuration of a monitoring device according to the present invention. Here, a case where the measurement target is a voltage value (analog value) in a nuclear power plant will be described as an example.

As shown in FIG. 2, the monitoring device of this embodiment includes an analog multiplexer 11, an address generation circuit 12, a buffer amplifier 13, an A/D converter 14, and a parallel/serial (P/S) conversion circuit 15. and an automatic transmission circuit 16.
A transmitting section consisting of an electrical/optical conversion circuit 17, a serial transmission line 18, an optical/'RS conversion circuit 19, a serial/parallel (S/P) conversion circuit 20, a timing circuit 21, and a 2-point RAM 22. and the central processing circuit (hereinafter referred to as C
The receiving unit is composed of a receiving unit (referred to as PU) 23.

Here, the analog multiplexer 11 inputs voltage signals (1 to k) that are a plurality of data output from a plurality of voltage measurement circuits (not shown), and sequentially switches one voltage signal among these (1 to k). It is selected and output. The address generating circuit 12 is composed of, for example, a counter, and generates an address of a data storage location of the receiving section in response to each voltage signal selectively outputted from the analog multiplexer 11. That is, automatic transmission circuit 1
The address is increased by one for each timing signal from 6, and the voltage signal selected by the analog multiplexer 11 is sequentially changed as (1)>(2)>(3)>...>(k). be. Further, the A/D converter 14 converts the voltage signal inputted from the analog multiplexer 11 via the buffer amplifier 13 into a digital code.

In this case, the input voltage may be held using a sample-and-hold amplifier or the like, if necessary.

The parallel/serial (P/S) conversion circuit 15 is composed of, for example, a shift register capable of parallel/serial conversion, and converts a parallel digital code including data and addresses from the A/D converter 14 into a serial digital code. It converts it into a code and outputs it. In this case, parity pits, start bits, and stop bits may be added as necessary. Furthermore, the automatic transmission circuit 16 is composed of a timing generation circuit that uses the frequency-divided output of a crystal oscillation circuit, for example.
5, transmission commands are issued at regular intervals. The electrical/optical conversion circuit 17 converts the serial digital code output from the parallel/serial (P/S) conversion circuit 15 from an electrical signal to an optical intermittent (on/off) signal. Furthermore, the serial transmission line 18 is made of, for example, an optical fiber line, and connects the transmitting section and the receiving section.

On the other hand, the optical/electrical conversion circuit 19 converts the optical signal sent from the transmitter via the serial transmission line 18 into an electrical signal (serial digital code). Further, the serial/parallel (S/P) conversion circuit 20 is composed of, for example, a serial/parallel conversion shift register,
It converts the serial digital code from the optical/electrical conversion circuit 19 into a parallel digital code consisting of an address and data and outputs it. When a parity bit, start bit, and stop bit are added, an error signal based on error determination based on these is input to the timing circuit 21 along with the received signal. in this case,
The parity pit, start bit, and stop bit are
This can be realized by a combination of an AND circuit and a comparison circuit.

Further, the timing circuit 21 generates a write signal only during normal reception based on the received signal and error signal from the serial/parallel conversion circuit 20, inputs it to the 2-point RAM 22, and outputs it from the serial/parallel conversion circuit 7. Data is written and stored in a location specified by an address among parallel digital codes. 2
The RAM 22 has two sets of data lines and address lines, and can be accessed from two directions simultaneously. That is, one port of the 2-point RAM 22 is connected to the data and address outputs of the serial/parallel conversion circuit 20, and receives a write signal from the timing circuit 21. Further, the other port of the 2-bot RAM 22 is connected to the CPU 2B, and can be read and written in the same way as a normal memory. Furthermore, CPU2B is RO
Memory such as M, RAM, I10 port, CRT, and other functional elements necessary for monitoring and control are added as necessary. , monitors and controls alarm output, etc.

Next, the operation of the monitoring device configured as above will be described.

In FIG. 2, the analog multiplexer 11 of the transmitting section
A plurality of voltage signals (1 to k) are input to the
~k) are sequentially switched and selected and output. Further, the address generation circuit 12 increments the address by one for each timing signal from the automatic transmission circuit 16, and the voltage signal selected by the analog multiplexer 11 is (1)>(2)>(3)>...・〉(k)
will be changed sequentially. The voltage signal selectively output from the analog multiplexer 11 is input to the A/D converter 14 via the buffer amplifier 13, and the voltage signal is converted into a digital code. Next, in the parallel/serial conversion circuit 15, a parallel digital code, which is a combination of the data from the A/D converter 14 and the address from the address generation circuit 12, is generated by a transmission command periodically generated from the automatic transmission circuit 16. It is converted into a serial digital code, and parity bits, start bits, and stop bits are added as necessary. The serial digital code from the parallel/serial conversion circuit 15 is input to the electrical/optical conversion circuit 17, where it is converted from an electrical signal to an optical intermittent (on/off) signal, which is then received through the serial transmission line 18. sent to the department.

In this case, in the transmitter, the number of bits M required for the data to be transmitted is determined based on the number N of measurement objects and the number Md of data bits.
is obtained as follows.

In other words, since the number of measurement targets N corresponds to the number of addresses, the number of bits Ma required for an address is Ma − [l
og (N −1)/log 2 (N>=2). However, [A] represents a natural number not exceeding A,
Further, when the number is N-1, Ma=1. Therefore, the number M of bits required for the data to be transmitted is M − Ma +Md. For example, the number of measurement objects is N-8. Data length Md-
If it is 12 bits, it is Ma-3, so M=15 bits, and a 15-bit digital code is transmitted from the transmitter to the receiver.

On the other hand, the optical/electrical conversion circuit 19 of the receiving section converts the optical signal sent from the transmitting section through the serial transmission line 18 into an electrical signal (parallel digital code), and the serial/parallel conversion circuit 20 converts the optical signal sent from the transmitting section through the serial transmission line 18 into an electrical signal (parallel digital code). and data are converted into parallel digital codes. Further, in this case, the received signal and an error signal based on the error determination based on the parity focus, start bit, and stop bit are input to the timing circuit 21 manually. Then, in the timing circuit 21, based on the received signal and error signal in the serial/parallel conversion circuit 20, a write signal is manually inputted to the 2-point RAM 22 only when reception is normal.
The data converted into parallel digital codes by the parallel conversion circuit 7 is stored at a location in the two-point RAM 22 designated by the address as shown in FIG. 4(a). In this case, the data is updated every time data is sequentially transmitted from the transmitter from 1 data (voltage signal) to 2 data from the measurement unit (voltage signal), and the update period is 1 data per data collection time plus transmission time. The time taken by adding up the data to ~ is the minimum. However, the update cycle can be further shortened by optimizing the timing of the transmission command in the automatic transmission circuit 16 in the transmission section and collecting the next data during data transmission.

Next, the CPU 23 executes the following steps according to the flowchart shown in FIG.
Necessary data is read out from the 2-point RAM 22, arithmetic processing is performed, and alarm output and the like are monitored and controlled. That is, in this embodiment, the 2-point RAM 2
Since the MSB of data No. 2 is connected to +5V (“1”), the MSB of data is always “1” when writing received data. Therefore, when the CPU 2B reads the memory contents (step Sl), it then writes "0" to the corresponding bit (MSB) (step S2).
, changes to 1 when the next data is read, thereby confirming that the data has been updated (step S3).

Here, the corresponding bit (MSB) of the read data is "]
”, it can be determined that the data has not been updated since the last time it was read, so abnormal processing required by the system, such as alarm output, is performed (step S4). If the relevant bit (MSB) of the data changes to “1”,
Since it can be determined that the system is normal, arithmetic processing is performed using the data, and monitoring and control of alarm output, etc. required by the system is performed (step S5).
. The CPU 2B periodically performs the processing shown in the flowchart of FIG. 3 above.

Here, as shown in FIG. 5(a), if the processing cycle of the CPU 23 is TX and the data collection cycle of the transmitter 24 is T2, in order for the data to be updated at least once during processing by the CPU 23, , T2 must be T1. In other words, when T2>T1, the CPU 23 waits for the transmission data to be updated, reducing processing efficiency. Furthermore, compared to the conventionally adopted transmission method as shown in FIG. 5(b), when the number of measurement points is N, the processing period T, -
Nx t1+Computation time excluding CPU 23 transmission (N locations) Processing period T-, ヰNxt-,+Computation time excluding CPU 23 transmission (N locations). That is, in this embodiment, since tl is the minimum (memory read time, etc.), the processing cycle of the CPU 23 can be minimized, and the processing speed of the monitoring device can be improved. In FIG. 5(b), 26 is an AJJ constant section, and 27 is a transmission circuit.

As described above, in the monitoring device of this embodiment, the address generation circuit 12 and the automatic transmission circuit 16 perform sequential signal selection digital encoding and serial signal conversion in the transmitting section, so it takes a very long time. It becomes possible to perform efficient data collection. In addition, in the receiving section, the 2-port RA added in the transmitting section
Since data is directly written and stored in the address of M22, high-speed data transmission is possible.

Furthermore, there is a 2-point RAM 2 from the measuring section of the transmitting section to the receiving section.
Up to 2 are completely independent of the CPU 23, and since the sending side rewrites data voluntarily, data processing can be performed independently of data transmission, saving time due to handshakes such as data requests. It becomes possible to eliminate losses and improve the processing speed of monitoring and control.

In other words, the CPO 23 can obtain the latest measurement data simply by reading the necessary data from the 2-point RAM 22, which minimizes the waiting time when collecting data and improves the response time of software for monitoring and control. It becomes possible to do so. On the other hand, in the past, the collection time varied depending on the type of data collection due to variations in time until transmission, and it was necessary to secure the maximum time as the data collection time during software design. In the example, data is read from the 2-bot RAM 22 in a fixed time, so there is no need for a data collection time margin (
It becomes possible to improve response speed. In addition, in the receiving section, part of the data in the 2-point RAM 22 is
Since the fixed data of o is written, it is possible to check whether or not the transmitted data has been updated, and it becomes possible to easily diagnose abnormalities in data transmission.

It should be noted that the present invention is not limited to the above embodiments, but can also be implemented as follows.

(a) As shown in FIG. 6, 2 in the receiving section of FIG.
Instead of the button RAM 22, a latch or buffer (F
Equipped with a parallel ψ shift register such as IFO),
Data may be written and stored in the latch or buffer 28 selected by the address decoder 29. In this case, the same function as the "0" write by the CPU 23 described above can be achieved by clearing the latch or buffer 28.

In this embodiment, not only the same effect as in the embodiment described in "-" is obtained, but also the CPU 2B uses a FIFO as a buffer that can store written data up to a certain amount in the order of writing. It is ideal for transmission circuits in monitoring equipment that require time-series processing, such as averaging using digital filters and measuring changes.

(b) As shown in FIG. 7, the automatic transmission circuit 7 in the transmission section of FIG. 1 generates a plurality of timing signals to the address generation circuit 3, thereby changing the transmission frequency according to the signals. (transmit each signal at a different period).

That is, if each signal has equal importance, then the signal (1
) -(2) -(3)-...-(k) The address generation circuit 3 may select the signals (1) to (k) sequentially as shown in -(1), but for example, if the signal ( 1) and (2
) is a signal related to plant safety and requires the fastest possible response, and other signals (3) to (k
) is a less important signal, signal (1) → (
2)→(3)-(1)-(2)-(4)-...=(1
)-(2)-(k)-(1)-(2)-(3)-...
By selecting the signals in the address generation circuit 3 as shown in FIG. This makes it possible to improve performance. Furthermore, this embodiment has extremely large advantages in terms of cost and space, compared to a method in which only signals (1) and (2) are separated into separate devices.

(c) As shown in FIG. 8, the transmitter in FIG. 1 is provided with a clock circuit 30 (or a counter circuit in place of this) for the transmission data group, and the time data is input to the switching circuit 2. The time data at which the data was collected may also be transmitted together with the data. In this case, the storage circuit 8 in the receiving section
The stored contents are shown in FIG. 4(b). moreover,
In this embodiment, the time index is manually inputted from the clock circuit 30 to the parallel/serial conversion circuit 4 and converted into each data.

The data is sent with a time index that can be determined to be collected at the same time. Here, the time index is something that is transmitted as lower-order data of the clock circuit 30 (or a counter circuit replacing it) by adding a portion that is sufficiently long compared to the calculation cycle of the calculation processing circuit 10 to the data. This enables processing that requires time information, such as simultaneous data processing and time elapsed measurement since the previous time. In this case, the stored contents of the storage circuit 8 in the receiving section are as shown in FIG. 4(C).

(d) Two receivers may be connected to one transmitter to form a backup circuit. That is, since a system failure is serious in the monitoring of a nuclear reactor in a nuclear power plant, it is necessary to improve reliability by adopting such a configuration, and it is possible to obtain a tremendous effect.

〔Effect of the invention〕

As explained above, according to the present invention, an address corresponding to the storage circuit of the receiving section is added to the data measured in the plant, and this is automatically transmitted periodically as a serial signal from the transmitting section. The signal is stored in the memory circuit of the receiving section at a location specified by the address, and the necessary data is read out from the memory circuit by the arithmetic processing circuit independently of transmission, and arithmetic processing is performed for monitoring and control. Therefore, it is possible to provide an extremely reliable monitoring device that can reduce the number of cables and devices, improve noise resistance, and increase data transmission speed to achieve high-speed response.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a monitoring device according to the present invention, and FIG.
FIG. 3 is a block diagram showing an embodiment of the monitoring device according to the present invention, FIG. 3 is a flow diagram for explaining the operation of the same embodiment, FIG. FIG. 5 is a diagram for explaining the functions and effects of the same embodiment, and FIGS. 6 to 8 are block diagrams of essential parts showing other embodiments of the monitoring device according to the present invention. DESCRIPTION OF SYMBOLS 1... Measuring section, 2... Switching circuit, 3... Address generation circuit, 4... Parallel/serial conversion circuit, 5...
・Automatic transmission circuit, 6... Serial transmission line, 7... Serial/parallel conversion circuit, 8... Memory circuit, 9...
- Timing circuit, 10... Arithmetic processing circuit. Applicant's representative Patent attorney Takehiko Suzue Figure 3 Figure 8-゛-shi L'J ('J

Claims (1)

[Claims] A monitoring device that measures, monitors and controls process quantities such as pressure and temperature, and radiation levels in a plant, comprising: a plurality of measurement units that measure process quantities and radiation levels;
a switching circuit that inputs a plurality of data outputted from the measurement section, sequentially switches and selects these, and outputs them as data to be transmitted; and a receiving section data storage corresponding to each data selected and outputted from the switching circuit. An address generation circuit that generates a location address, and a parallel/parallel converter that converts a plurality of parallel digital codes, which are a combination of the data from the switching circuit and the address, into serial digital codes and transmits the serial digital codes.
A transmitting unit comprising a serial converter circuit and an automatic transmitting circuit that generates a timing signal to the address generating circuit and a transmission command to the parallel/serial converter circuit at a constant cycle, serial transmission from the transmitting unit A serial/parallel conversion circuit receives a serial digital code sent through a cable, converts it into a parallel digital code consisting of an address and data, and outputs it, and a parallel conversion circuit outputs from the serial/parallel conversion circuit. a memory circuit that writes and stores data in a location specified by an address in the digital code; a timing circuit that creates a write signal for the memory circuit based on a signal received by the serial/parallel conversion circuit; 1. A monitoring device comprising: a receiving section comprising an arithmetic processing circuit that reads out and arithmetic-processes necessary data, and monitors and controls alarm output, etc.