EP0056099A2 - Supervisory apparatus for remote-control systems - Google Patents

Abstract

1. A monitoring device for remote control devices with at least one central station (1) and with subsidiary stations (2) where the stations (2) exchange items of information via a common transmission link (3) by means of time-consecutive pulse telegrams, and the pulse telegrams contain an address component, an information component, and a differentiation criterion which, depending upon whether tha pulse telegram in question emanates from a central station (1) or a subsidiary station (2), is a central station telegram criterion or a subsidiary station telegram criterion, and where both the interrogation telegram and the associated response telegram have the same address, and the monitoring device which can be connected to the transmission link (3) includes analysis device (5) which serves to analyse the pulse telegrams transmitted on the transmission link (3) in respect of their address and differentiation criterion, characterised in that the transmission device includes display means for the display of the address and the differentiation criterion, and that the differentiation criteria which are determined by the analysis device (5) can be monitored by means of a monitoring arrangement (7) in such manner that interruptions, which exceed a predetermined length of time, in the occurrence of central station telegram criteria (Z) trigger an alarm signal.

Description

The invention relates to a monitoring device for telecontrol devices with at least one central station and with substations, the stations using a common transmission path by means of pulse telegrams that follow one another in time. exchange and the impulse telegrams contain an address part, an information part and a differentiation criterion which, depending on whether the impulse telegram in question originates from a central station or substation, is a central station criterion or substation criterion, and the query telegram and the associated response telegram have the same address. The pulse telegrams can be used in addition to the address part, information part and differentiation criterion e.g. have a synchronous character, a fuse attachment and / or the like.

A telecontrol device, as is required for such a monitoring device, is already known (Siemens-Zeitschrift, 48th year (1974), Supplement to news transmission technology, pages 292 to 294).

For the display of the addresses of transmitted or received telecontrol telegrams, the contents from the corresponding counters or memories of the telecontrol center can be displayed. If the head office is disturbed, the meaningfulness of these displays is very low or the displays themselves are even disturbed. Such a display is therefore not suitable for monitoring the telecontrol center itself.

The object of the invention is to design a monitoring device of the type specified above in such a way that the function of at least one central station is monitored with particularly great reliability. One finding within the scope of the invention is that this is expediently carried out in connection with an observation of the telecontrol telegrams transmitted on the transmission link.

According to the invention, the monitoring device is designed to solve this problem in such a way that the monitoring device which can be connected to the transmission link contains an evaluation device for evaluating the pulse telegrams transmitted on the transmission link with regard to the address and the differentiation criterion and display means for displaying the address and the differentiation criterion and that of distinguishing criteria determined by the evaluation device can be monitored by means of a monitoring arrangement in such a way that interruptions in the occurrence of central station criteria which exceed a predetermined time period trigger an alarm signal. The monitoring device can be connected to the transmission link via its own modem or a modem of the central station or a substation. In particular, a certain bit of the telecontrol telegram can serve as the distinguishing criterion, the logical "1" being the central station criterion and the logical "0" being the substation criterion. The monitoring device is preferably located at the location of the telecontrol center or - if there are several telecontrol centers - at least at the location of one of the telecontrol centers. However, it can also be arranged as a test device at another point on the transmission link.

The measures mentioned have the advantage that the telecontrol device can be monitored particularly reliably to determine whether there are central telegrams at regular intervals on the transmission link formed, in particular, by a line common to all stations. If this is not the case, a failure alarm is issued.

The monitoring device is particularly advantageous for telecontrol devices with several central stations, in which an initially active central station is replaced in the event of a fault by a further central station, which changes from the passive to the active state as soon as it no longer receives central telegrams after a certain waiting time. If a monitoring device located at one of such central stations detects that no more central telegrams are being transmitted, it is namely certain that the central station in question itself has failed.

In a further development of the invention, the monitoring device can be further perfected by the fact that the monitoring device is spatially adjacent to a central station and that, in addition to the central station criteria, test pulse sequences formed in the central station can also be monitored by means of the monitoring arrangement in such a way that interruptions in the occurrence exceeding a predetermined time period trigger an alarm signal from test pulses. These measures advantageously make it possible to determine malfunctions in a central station in telecontrol devices with a plurality of central stations even when another central station is sending the query telegrams.

In a further embodiment of the invention, the monitoring devices of a central station are arranged spatially adjacent and a criterion obtained from the alarm signal is fed to the start input of a device for sequence control contained in the central station as a start signal. An automatic start that tries to restart a microcomputer system of the central can be switched on as soon as the central station no longer sends telecontrol telegrams or is recognized as faulty. In particular, such starting attempts consist in resetting a device for sequence control to a zero position, from which it automatically starts again.

The differentiation criterion can be displayed by means of a separate light-emitting diode, which is arranged adjacent to the device for address display.

The monitoring device is expediently designed such that the display means for displaying the telegram address and the differentiation criterion contain a numerical display element with additional characters, in particular a decimal point, and that a control signal derived from the differentiation criterion is fed to the input of the numerical display element which is assigned to the decimal point. Central telegrams and station telegrams can be clearly distinguished from one another in the optical display using particularly simple means, although the query telegram from the telecontrol center and the subsequent response telegram from a substation each have the same telegram address. The additional optical character used to distinguish query and response telegram addresses advantageously does not require any special effort. E.g. additional characters such as +, - ,: or the like can be used.

The check as to whether central telegrams are on the line at regular intervals is expediently carried out in that the monitoring arrangement for evaluating the distinguishing criterion contains a counter, the clock input of which is connected to a clock generator of the monitoring device, the reset input of which can be acted upon with control signals derived from the central station criteria and whose advancement can be blocked when a predetermined counter reading is reached.

The monitoring of test pulse sequences formed in the central station is expediently achieved in that the monitoring arrangement contains at least one counter, the clock input of which is connected to a clock generator and the reset input of which is connected to the output of a test device contained in the central station, which, at undisturbed operation, provides test pulses at regular intervals delivers.

In a further embodiment of the invention, the monitoring device is designed such that the monitoring arrangement contains a counter, the clock input of which is connected to a clock generator and the reset input of which can be acted upon by the clock pulses of a clock generator contained in the central station. The further counter advantageously makes it possible to reliably monitor the correspondence between the clock of the remote control center and the clock used in the monitoring.

If the additional character of the numerical display element can be controlled by the control signal in such a way that it is activated when the substation criterion is present, the result of the sequence of telecontrol telegrams running over the transmission link is particularly easy to recognize.

In particular, the clock frequency can be set to the bit repetition frequencies that can be selected in the telecontrol device with regard to its clock frequency.

The invention is explained in more detail with reference to the embodiment shown in the figure.

The figure shows a monitoring device which is connected to a central station.

In the monitoring device shown in the figure, the central station 1 is connected to the transmission line 3 via the modem 10. The transmission line 3 connects the central station 1 to the substations and possibly to further central stations, of which only the substation 2 is shown with its modem 20.

The telecontrol telegrams transmitted from the central station 1 to the modem 10 or from the modem 10 to the central station 1 are fed to the monitoring device 5 via the decoupling diodes 61, 62. The monitoring device 5 evaluates the data stream. The arrangement 51 contained therein, which essentially consists of a shift register which can be controlled by the clock generator 6, receives the pulse telegrams and, after a serial-parallel conversion, forwards them on its output bus byte by byte to the device 52 for synchronous character evaluation. If the device 52 recognizes a synchronous character, it releases the control device 53. The control device 53, which is connected to the clock generator 6, starts counting the clock pulses from the time of the release and, when a predetermined number of clock pulses is reached, outputs a strobe pulse as a logic “1” to the control circuit 42. The drive circuit 42, the is connected to the arrangement 51 via a seven bit wide address bus, is caused by the strobe to adopt the binary coded address.

The control circuit 42 is used to control the device 41 for numerical display. It contains an address memory and one or more encoders, with the aid of which the control signals required for controlling the device 41 for numerical display are obtained from the binary-coded address information. In an intermediate stage, the address is preferably first converted into the BCD code and then subsequently into the control signals customary for controlling 7-segment display elements.

The device 41 for numerical display contains a display element which serves to display a decimal point. This display element is controlled separately via the D flip-flop 54. This D flip-flop 54 is connected to the output of the control device 53 with its clock input and to a connection of the output of the arrangement 51 with its D input.

The telecontrol telegrams on which the exemplary embodiment is based are composed of several bytes each with 8 bits. The telecontrol telegram begins with a synchronous byte. Another byte serves as an address byte and consists of a so-called Z-bit, which serves as a differentiation criterion, and seven address bits.

If the address byte is at the output of the arrangement 51.., the D flip-flop 54 is caused by the strobe pulse of the control device 53 to take over the Z bit and appears at the output of the D flip-flop as a control signal for the additional character of the device 41 a stored central station criterion Z 'as a logical "1".

_'The monitoring device 5, the clock generator 6 and the drive circuit 42 may be of a small microcomputer system are constructed in particular with the aid.

The monitoring arrangement 7 contains the counters 71, 72 and 73, which are each connected to the clock generator 6 with a clock input. The advancement by the clock is blocked when the counter end position is reached in that the output of the counter is connected to an enable input E. The outputs of the counters 71, 72 and 73 are also routed to the inputs of the triple-OR element 74, the output of which is routed both to the display device 75 and via the automatic start device 9 to the reset input R of the central station 1. In a modification of the exemplary embodiment shown, the alarm signals of the counters 71, 72, 73, on the other hand, can be displayed individually or only in part, or can be fed to the automatic start.

The counters 71, 72 and 73 designed as binary counters are reset in different ways.

The counter 71 is connected with its reset input R to the output of the AND gate 55, which has one input together with the D input of the D flip-flop 54 at a connection of the output of the arrangement 51 and with the other input on Output of the control device 53 is. The AND gate 55 queries the Z bit supplied by the arrangement 51 with the aid of the strobe signal emitted by the device 53. The counter 71 is therefore reset with each central station telegram. If central station telegrams are missing during a predetermined period of time, the counter 71 reaches its end position and emits an alarm signal to the OR element 74.

The reset inputs of counters 72 and 73 are dynamic inputs that only respond to positive clock edges.

The reset input R of the counter 72 is connected to a clock output of the central station 1, which is also connected to a clock input of the modem 10. The counter 72 therefore monitors the clock pulse sequence of the central station 1.

The reset input of the counter 73 is connected to a test pulse output S of the central station 1. The device for sequence control of the central station 1 sends monitoring pulses to the test pulse output at regular intervals, even when another central station sends query telegrams to the transmission link and the central station under consideration must therefore remain passive.

From the address bytes of the telecontrol telegrams, the so-called Z-bit is evaluated as a differentiating criterion and used to control three different functions: As control signal Z ', it controls an optical display for identifying the substation telegrams, which is formed by the decimal point of the device 41 for the numerical display. If the Z bit is missing during a certain period of time, the LED 74 of the display device 75 is activated via the OR gate 74 to emit a central alarm. In addition, this alarm causes the automatic start 9 to restart a microprocessor which is used to control the sequence of the control center 1. This automatic start 9 is formed by a clock pulse generator, which emits start pulses at regular time intervals when it is released by an alarm signal via its enable input E.

The device 41 for digit display makes the addresses of the telegrams running via the telecontrol network and thus the cycle sequence and the telegram exchange visible. The telegram addresses of the telecontrol telegrams are displayed on the device 41 for numerical display. The decimal point is used to display substation telegrams. The display remains until a new telegram arrives.

The monitoring device has its own clock supply which is independent of the sequence control of the central station 1 and therefore also recognizes malfunctions of the sequence control which are caused by a faulty clock.

The own clock supply also makes it possible to use the monitoring device as a service and / or test module in the entire telecontrol network to control the exchange of telegrams. In this case, only the clock generator 6, the device 5 for telegram evaluation and the device 41 with the control circuit 42 are used.

Claims (9)

1. Monitoring device for telecontrol devices with at least one central station and with substations, the stations exchanging information over a common transmission path by means of pulse telegrams that follow one another in time, and the pulse telegrams contain an address part, an information part and a differentiation criterion, depending on whether the relevant pulse telegram from a central station or substation, is a central station criterion or substation criterion and the query telegram and the associated answer telegram each have the same address, characterized in that the monitoring device which can be connected to the transmission link (3) has an evaluation device (5) for evaluating the transmission link (3) transmitted pulse telegrams with respect to the address and the differentiation criterion and display means for displaying the address and the differentiation criterion and that the v Differentiation criteria determined on the evaluation device (5) can be monitored by means of a monitoring arrangement (7) in such a way that interruptions in the occurrence of central station criteria (Z) which exceed a predetermined time period trigger an alarm signal. 2. Monitoring device according to claim 1, characterized in that the monitoring device of a central station (1) is arranged spatially adjacent and that by means of the monitoring arrangement (7) in addition to the central station criteria (Z) also formed in the central station (1) test pulse sequences can be monitored, that interruptions in the occurrence of test pulses which exceed a predetermined time period trigger an alarm signal. 3. Monitoring device according to claim 1 or 2, characterized in that the monitoring device of a central station (1) is arranged spatially adjacent and that a criterion obtained from the alarm signal the start input (R) of a device for sequence control contained in the central station (1) is supplied as a start signal. 4. Monitoring device according to one of claims 1 to 3, characterized in that the display means for displaying the telegram address and the differentiation criterion contain a numerical display element with additional characters, in particular a decimal point, and that a control signal (Z ') derived from the differentiation criterion is fed to the input of the numerical display element which is assigned to the decimal point. 5. Monitoring device according to one of claims 1 to 4, characterized in that the monitoring arrangement (7) for evaluating the differentiation criterion (Z) contains a counter (71), the clock input of which is connected to a clock generator (6) of the monitoring device, the reset input (R ) can be acted upon with control signals derived from the central station criteria (Z) and its further switching can be blocked when a predetermined counter reading is reached. 6. Monitoring device according to one of claims 1 to 4, characterized in that the monitoring arrangement (7) contains at least one counter (73), whose clock input is connected to a clock generator (6) and whose reset input (R) with the output of one in the central station (1) included The test device is connected, which emits test pulses (S) at regular intervals in the event of undisturbed operation. 7. Monitoring device according to one of claims 1 to 4, characterized in that the monitoring arrangement (7) contains a counter (72) whose clock input is connected to a clock generator (6) and whose reset input (R) with the clock pulses in the central station (1st ) included clock is acted upon. 8. Monitoring device according to claim 4, characterized in that the decimal point of the numerical display element (41) can be controlled by the control signal such that it is activated when the substation criterion is present. 9. Monitoring device according to one of claims 5 to 8, characterized in that the clock (6) is adjustable in terms of its clock frequency to selectable bit repetition frequencies in the remote control device.

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