JPS5910101B2 - data transmission system - Google Patents

Description

[Detailed Description of the Invention] 5 [Field of Application of the Invention] The present invention relates to a data transmission system, particularly in a system such as a nuclear reactor containment vessel, where entry by operators and maintenance personnel is prohibited for a long period of time during plant operation. The present invention relates to a system suitable for data transmission within a building.

o [Background of the Invention] A reactor containment vessel houses the main parts of a nuclear power plant, such as the reactor pressure vessel and primary cooling piping system inside the reactor core, and is hermetically sealed during plant operation.
Even in the unlikely event of an accident, it prevents the spread of accidents and maintains the five safety standards of the plant.

Therefore, during normal plant operation, operators and maintenance personnel are not allowed to enter for a long period of about one year.

Conventionally, a containment vessel has been equipped with a transmission path for measuring information related to pressure, temperature, flow rate, etc.

These lines comply with the rules of system separation, avoid multiplexing, and serve as redundant transmission lines. However, the existing measurement information network mentioned above is limited to those essential for plant operation in order to avoid complication of transmission lines due to redundancy and an increase in the number of cables.

Therefore, in order to collect information on minute leaks in the piping system and abnormal sounds that may occur inside the containment vessel, and to monitor the situation inside the containment vessel in more detail, it is necessary to construct a new data transmission network. Is required.

Since this data transmission line handles secondary information that deviates from the above-mentioned minimum range of information essential for plant operation, the system separation rules are not applied. Furthermore, since the information becomes more detailed, it is preferable to employ multiple transmission lines in order to avoid congestion on the transmission lines. FIG. 1 conceptually depicts multiple transmission paths for transmitting detailed information within the containment vessel from the above perspective.

Inside the containment vessel 5 is a detector 4 that detects minute leaks and abnormal sounds.
are placed at various locations, and the nearby local stations LS(1),..., LS(K),...
..., connected to LS(N).

These local stations share data signal transmission path 1 and power supply path 2 with the central station CS.
are tied together. 3 is a transmission path for answer back signals from the local station.

Now, assign an address to each local station in advance. In response to an address signal sent from the central station CS through the data signal transmission line 1, the designated local station detects the detector 4.
The data taken in from the central station CS can be sent as an answer/back signal to the central station CS via the data signal transmission line 1 and the answer/back signal transmission line 3. In general, in this type of multiplex transmission system, the problem in terms of reliability is how to prevent this failure from spreading to the common transmission path when a failure occurs at the local station. It's up to you.

An effective method aimed at solving this problem is shown in Figure 2.
It is a bypass relay method and is applied to general computer control data transmission systems.

In this method, relay contacts Sl and S2 are provided on the data signal transmission path 1 passing through the local station LS', and in normal times, by energizing the relay coil S, the relay contacts S, S2 are Switching to the broken line side, data signals are sent and received between the central station CS and the local station LS', and when the local station LS7 fails, the power supply 15 is lost and the relay coil S is returned to the normal state. relay contact, SL
, S2 are connected to the bypass path 10 as shown by solid lines. Here, 11 is a receiving circuit, and 12 is a processing circuit.

The processing circuit 12 decodes the sent command, takes in measurement data from the detector 4, edits the answer/back signal, etc. Each local station is given a specific address.The data signal transmitted from the central station CS is given an address signal, and the processing circuit 12 decodes the instructions in the data signal. The address signal is decoded prior to the decoding of the address signal.

If this address signal matches the address of the local station LS', the processing circuit 12, according to the instructions in the data signal, will e.g. The information with the added information is edited as an answer/back signal. Thereafter, this answer back signal is returned to the central station CS via the transmission circuit 13, relay contact S2, data signal transmission line 1 and transmission line 3. In this way, data transmission systems, in principle,
In response to an inquiry from the central station to a local station, the relevant local station responds to the central station CS with information regarding the inquiry as an answer back signal. Further, 13 is a transmitting circuit, and 14 is a failure detection circuit. The failure detection circuit 14 is a circuit that checks whether there are any errors in the processing contents of the processing circuit 12, and has a function of, for example, causing the power supply circuit 15 to be lost if an error continues for a certain number of times or more. However, the failure detection circuit 14 is intended to detect errors after reception or before transmission, and cannot detect reception failures, transmission errors, or failures in the failure detection circuit itself.

These failures are ultimately detected by the central station CS by analyzing the answer back signals from its local stations.

This detection method includes (1) a parity check, (2) a method based on the self-diagnosis results of the local station, and (3) a check for the validity and rationality of the information content of the answer back signal. It is something. Specifically, the method (2) is carried out by reading the self-diagnosis result by the failure detection circuit 14 of the local station LS' from the answer back signal. Method (3) is to answer the question from the central station CS.
- An abnormality is determined when the Cal Station LS' sends back an answer back signal with invalid information. For example, if the rate of change of the pressure sensor value within the sampling time so far is 0.4 and the previous answer/back signal shows 2.0, the current answer/back signal shows 2.0.
It should be around 4. However, if the value suddenly shows 9.7, this is an unlikely value and it is determined that there is some kind of abnormality in the local station LS'. When the central station CS detects a failure based on the answer back signal of the local station, an operator goes to the site and turns on the power switch 16 of the power supply line 2' connected to the power supply line 2. It's starting to cut.

That is, in conventional general computer-controlled transmission systems, the power source for the local station, including the detector and controlled equipment, is procured on-site from the nearest distribution board. For this reason, when a local station breaks down, it is common practice to manually turn off the power switch for that station on site. Therefore, this method is unsuitable for a data transmission system inside a containment vessel in which the power transmission path is common and access is not easily permitted.

[Object of the Invention] An object of the present invention is to provide a data transmission system that can remotely disconnect a failed local station from a data signal transmission path and a power supply path.

[Summary of the invention]

The gist of the present invention is to add a new control line, and when the central station detects a failure in a local station from the answer back signal, selects the failed local station via this control line, and The purpose is to blow out the fuse in the power supply circuit.

[Embodiments of the invention]

A Kth local station LS(K) according to an embodiment of the invention is shown in FIG.

Parts given the same numbers as in FIG. 2 indicate that they have the same functions.

Note that the solid line of the relay contact indicates the contact position in the non-energized normal state, and the broken line indicates the energized state. 7 is central
This is a control line connected to the station CS.

40 is a fuse, which is connected to the ground side terminal α of the power supply circuit 15.
is connected to via relay contact q.

41 is a resistor for current adjustment.

A counting circuit 200 is a flip-flop type relay circuit that counts voltage pulses applied from the central station CS to the excitation coil P via the control line 7.

Note that the contact point operated by the excitation coil P is P. ,Pl
and A for excitation coil A. , a, , a2 and A3 contacts operate. The same applies to exciting coils B, C, D and Q. 300 corresponds to the number of pulses applied to the control line 7.

This is a recognition number setting circuit for the local station LS', which is determined separately from the address number to be verified by the processing circuit 12 as described above. This identification number is
Any number can be taken depending on how the wires 31, 32, and 33 are connected, but they are fixed when the local station LS' is installed. In addition, local station LS (K
), similarly to the local station LS' described above, the processing circuit 12 responds to the command of the data signal if the address signal given to the data signal transmitted from the central station CS matches its own address. Therefore, an answer back signal containing the measurement data from the detector 4, the self-diagnosis result of the local station LS(K), and the parity bit is output. This answer back signal is sent from the transmitting circuit 13 to the central station CS. Although not shown in FIG. 3, the self-diagnosis of the local station LS(K) is performed by the fault detection circuit 14 upon receiving a signal from the processing circuit 12, as in FIG. The function of the failure detection circuit 14 to cause the power supply circuit 15 to be lost is the same as in the case of FIG. When the central station CS receives an answer back signal from the local station LS (K), it analyzes the answer back signal based on items (1) to (3) as described above, and sends the answer back signal to the local station LS(K). Determine whether there is a failure in LS(K).

The time chart shown in Figure 4 shows the operation from when the central station CS detects that a failure has occurred in the local station LS (K) until it disconnects the local station LS (K). Explain using. First, the voltage s applied to the power supply line 2 is set to the normal voltage.

When the central station CS detects a failure,
K voltage pulses Vc are applied to the control line 7. As a result, the excitation circuits P, A, and C operate at 1, 2, and 3 of the pulse voltage c.
, . . . operates as shown in the time chart shown in the figure. When the central station CS applies the first pulse of the pulse voltage Vc to the control line 7,
When this pulse takes a high value (ie, logic 1), the excitation coil P is energized.

Therefore, due to this excitation coil P, the contact P1 corresponding to this coil is switched to the excitation state side. That is, the connection is opposite to that of the contact P1 shown in FIG. (However, contact P
. Regarding, there is no change as shown in the figure. ) This contact P,
Due to this switching, a current path is formed from the power supply path 2 to the ground via the excitation coil A1 contacts Bl, P, so the excitation coil A becomes excited. Contact A is activated by excitation of excitation coil A. , al, and a2 are switched to the excited state side (opposite to the illustrated contact position). By switching contact A, power supply path 2 → excitation coil A → contact b1 → contact P1
In addition to the current path of → ground, current paths of power supply path 2 → exciting coil A → contact B, → contact a1 → ground are formed, but the excitation state of exciting coil A remains unchanged. In addition, even if contact A2 switches, contact P1 switches to the excitation side (opposite to the contact position shown in the figure), so the current flows to the excitation coil B.
, and the excitation coil B is not excited. That is, in the first stage flip-flop type relay circuit, the excitation coil A is held in an excited state. On the other hand, in the second stage flip-flop type relay circuit, the above-mentioned contact A is switched to the excitation side, so that the current supply path 2 → excitation coil C → contact D
, →Contact A, →The excitation coil C is excited by the formation of the ground.

This results in contact point C. is switched to the excitation side (same as the contact position shown in the figure), and the contacts C, , c are also switched to the excitation side (opposite to that shown). Even with this, no current path passing through the excitation coil D is formed, so the excitation coils C and D are held in the energized and de-energized states, respectively. be done. In the above holding state, the contacts PO and cO of the identification number setting circuit 300 remain in the excited state as shown in the figure.

However, contact point A. is in an excited state, which is opposite to that shown in the figure. Therefore, a current path from the current supply path 2 to the ground through the exciting coil Q is not formed, so the exciting coil Q is not excited. As described above, when the first pulse of the pulse voltage c rises, the excitation coils A, C, and Q are stably maintained as being energized, energized, and de-energized, respectively.

This situation is shown in the time chart of FIG.
Next, the first pulse of the pulse voltage Vc falls,
Takes logical value 0. This corresponds to the fact that the voltage applied to the control line 7 has deteriorated, so the excitation coil P is de-energized.
Therefore, the contact P1 corresponding to the excitation coil P is switched to the non-excitation side (same contact position as shown in FIG. 3), and the power supply path 2
A current path of →excitation coil B→contact B2→contact A, →contact P1→earth is formed, and the excitation coil B is excited.
Due to the excitation of excitation coil B, contacts Bl and b2 switch to the excitation side, power supply path 2 → excitation coil A → contact b1 → contact A2 → contact P1 → ground, and power supply path 2 → excitation coil B → contact B2. A current path from → contact a1 → ground is formed. As described above, after the first pulse of pulse voltage c falls, both exciting coils A and B are held in the excited state.

Note that the excitation of the excitation coil C and the de-excitation of the excitation coil D remain unchanged. Next, when the second pulse of the pulse voltage Vc rises and assumes logic 1, the excitation coil P is excited again, so the contact P1 switches again to the excitation side (the contact position is opposite to that shown). For this reason, exciting coil A→contact b1→
The current path passing through contact A2 is broken at contact P1.
Therefore, the excitation coil A becomes de-energized. On the other hand, the current path of power supply path 2→excitation coil B→contact B2→contact P1→ground is maintained as it is, so B is excited. In addition, contact point A. , a, , a2, a3 return to the non-excited side (same as shown). In the second stage flip-flop type relay circuit, power supply path 2 → exciting coil C → contact d1 → contact C1 →
Since the current path to ground is maintained, the excitation coil C remains energized. Further, since a current path is formed such as power supply path 2→excitation coil D→contact D2→contact C2→contact A,→earth, the excitation coil D is excited and the contacts D, d2 are switched to the excitation side. Even with this, the excitation states of the excitation coils C and D do not change. As described above, when the second pulse of the pulse voltage Vc rises, the excitation coils A and C are de-energized and excited, respectively. Also, contact point A. is on the excitation side (opposite to that shown), so the excitation coil Q is non-excited. The waveform values of these excitation coils A, C, and Q are shown in FIG. 4 corresponding to the second pulse voltage c. In this way, in response to the pulse of the pulse voltage Vc, the exciting coils A,
The combination of excitation of B, C, and D changes, and it operates as a counter that counts pulses as shown in the time chart of FIG.

That is, the "excitation" and "de-excitation" of the excitation coils are set to negative logic and have logical values "O゛" and "1", respectively. At the first pulse of the pulse voltage c, the excitation coils C and A are respectively in the excitation state. Therefore, the 2-bit value indicated by the excitation coils C and A is 100°.Hereafter, 2, 3, 4, .
601, 110, 611'' corresponding to the . The excitation coils C and A sequentially change their energized and de-energized states by counter operation in response to the input number of pulses of the pulse voltage c described above.

Pulse voltage Vc(7) When the Kth pulse is applied,
Since the excitation coils P and C are energized and the excitation coil is de-energized, the wiring in the identification number setting circuit 300 is connected to the switch P.
.

, aO, and cO, the excitation coil Q is excited, and the contact q falls to the β side shown in the figure. Here, when an overvoltage H is transiently applied to the control line 7, an overcurrent flows through the illustrated path 50, and the fuse 40 is blown. Note that in the example of FIG. 3, the contact C in the setting circuit 300.

, aO become as shown when the excitation coils C and A are energized and de-energized, respectively. Also, contact point P. The coil P is excited every time the pulse voltage Vc is input, and the contact position is as shown. At the illustrated positions of the contacts CO and aO, the above negative logic becomes "01n. Therefore, the Kth corresponds to K-2 when compared to the illustrated contact positions. When there is no need to blow the fuse In this case, as shown in FIG. 4, if the voltage at Vs is briefly cut off at an arbitrary time Ts, the counting circuit is reset and returns to its initial state.
The contact q returns to the α side, that is, the normal state, and the bypass switches S, , S2 return to the β side, that is, the excited state, so that the local station LS(K) can be operated again.

However, as mentioned above, if the fuse is blown, the power supply circuit 15 will not operate even if the voltage s is temporarily cut off and the contact q is returned to the normal state, so the bypass switches Sl and S2 will not operate. It remains on the α side, that is, the bypass side.

Note that the overvoltage H is transiently applied to the excitation coil P connected to the control line 7.

However, if the exciting coil P is used for a relatively large rated voltage and the fuse is used to shorten the overvoltage application time, there will be no practical problem. In the manner described above, it is possible to disconnect any faulty local station and bypass the data signal transmission path and power supply path via the control line.

As a result, it is suitable for data multiplex transmission in reactor containment vessels that cannot be accessed by maintenance personnel for long periods of time, or in buildings in adverse atmospheres.
A highly reliable transmission system with a high survival rate will be realized.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a data transmission system, FIG. 2 is a system diagram of a conventional example of a local station used in FIG. 1, and FIG. local station tree,
FIG. 4 is a characteristic diagram showing the operation of FIG. 3. DESCRIPTION OF SYMBOLS 1... Data signal transmission line, 2... Power supply line, 3... Transmission line, 4... Detector, 7...... Control line, 10... Bypass path, 11... Receiving circuit, 12... Processing circuit, 13... Transmitting circuit, 14...... Failure detection circuit, 15... Power supply circuit, 40...
・Fuse, 200... Counting circuit, 300...
...Identification number setting circuit, A, B, C, D, P, Q.
...excitation coil, CS ... central
Station, LSl~LSn, LS(K)...
・Local station, SL, S2... Bypass switch.

Claims (1)

[Claims] 1. A central station, a plurality of local stations, a data signal transmission line connecting the central station and each of the local stations, and a power supply connecting the central station and each of the local stations. In the transmission system, the central station and each of the local stations are connected to a control line, and means for disconnecting the local station whose power is lost when the local station loses power from the data signal transmission path. A fuse is provided in a circuit for receiving power from the power supply line in each of the local stations, and a faulty local station is selected by the number of pulses applied to the control line. - A means is provided for connecting the fuse in the station to the control line, and by transiently passing an overcurrent through the control line to melt the fuse, the power supply circuit is cut off and the data signal is transmitted. A data transmission system characterized in that a power supply line and a power supply line bypass the failed local station.