GB2364807A

GB2364807A - Installation monitoring system

Info

Publication number: GB2364807A
Application number: GB0103043A
Authority: GB
Inventors: Jurgen Peissig
Original assignee: Sennheiser Electronic GmbH and Co KG
Current assignee: Sennheiser Electronic GmbH and Co KG
Priority date: 2000-02-12
Filing date: 2001-02-07
Publication date: 2002-02-06
Anticipated expiration: 2021-02-07
Also published as: DE10006313B4; FI20010209A; FI113715B; FI20010209A0; DE10006313A1; GB2364807B; GB0103043D0; NO317475B1; NO20010680D0; NO20010680L

Abstract

In an installation monitoring system, conditions at various sites of the installation are routinely monitored with a plurality of sensors (1-5). The actual signals of the sensors (1-5) are routinely stored via multiple channels in a first memory 24, and in the event of an alarm condition the actual signals lying chronologically around the alarm condition are transferred into a second memory 25 and then are subjected to a detailed automatic and/or manual examination by a supervisor. The sensors may be acoustic, optical or heat sensors. The installation may be a gas distribution plant which is monitored for leakage.

Description

2364807 Installation monitoripg syst%% The invention relates to an

installation monitoring system in which with a plurality of sensors conditions at various sites are routinely monitored in one or more monitoring units of an installation, the actual signals 10 derived therefrom are compared with set signals stored in a set-point memory and in the event of deviations an alarm condition is signalled and/or the installation or installation parts are shut down or switched off.

15 A method for locating and detecting leakage noise in a pipeline through which a medium flows is already known from German Patent Specification 37 26 585. Disposed in the vicinity of critical sites of such pipelines are microphones, the output signals of which are compared

20 with reference signals and if certain criteria are met an alarm or error report is emitted. However, frequently such alarm or error report also occurs if no error conditions at all have occurred at the installation to be monitored, but external interfering signals or other 25 influences have resulted in such an alarm or error report.

On account of these uncertainties in the automatic detection of error conditions, in many cases, instead of 30 automatic monitoring, monitoring is performed by experienced service personnel. In individual cases this results in a safe detection of the installation condition, but has the disadvantage that it is virtually Impossible to monitor complex installation parts extending over large three-dimensional areas since the attentiveness and aptitude of the supervisors cannot be maintained over 5 long period of time and great distances.

The object of the present invention is therefore to propose an installation monitoring system which also enables the monitoring of large and complex installations with great safety and reliability.

10 This object is achieved with an installation monitoring system of the type mentioned at the beginning in that the actual signals are routinely stored via multiple channels in a first memory and in the event of an alarm condition the actual signals occurring in a time interval 15 surrounding the occuj:rence of the alarm condition are transferred into a second memory and are subjected to a detailed automatic examination and/or manual examination by a supervisor. The system according to the invention is based on the principle of performing crude monitoring with 20 automatic monitoring means in a first step and in a second step of improving monitoring and making it safer by human intervention by means of one or more supervisors, in which case it is possible for the supervisor to check the installation condition subsequently by checking the 25 temporarily stored sensor signals.

If the installation to be monitored is, for example, a pipeline monitoring system, e.g. for a gas distribution installation, the sensors are preferably designed as air and/or structure borne sound sensors, which are disposed 30 at suitable sites of the installation. However, the error-free operation of machine parts such as pumps and compressors can also be monitored with such acoustic sensors. If acoustic sensors are used to ascertain noises in the installation, the subsequent manual examination by the supervisor is expediently performed by 5 monitoring the stored acoustic signals.

Since the storage of a plurality of actual signals of complex form signifies a comparatively high expenditure on memory, in accordance with an advantageous embodiment 10 of the invention the first memory is preferably a memory with limited capacity, which stores the actual signals just of a limited period of time and which is routinely overwritten by new actual signals. The second memory then takes over the actual signals transferred from the 15 first memory and stores them permanently for further manual evaluation. The actual signals transferred into the second memory are then fetched by the supervisor and examined; if necessary associated set signals are also fetched by the supervisor and compared with the actual 20 signals.

In complex installations, in order to enable comprehensive monitoring, sensors are preferably provided to monitor different types of physical quantity in the 25 installation, and the actual values of these sensors are then compared with corresponding stored set values for the detection of an alarm condition. Thus it is Possible, for example, apart from monitoring the installation by means of acoustic sensors, for other 30 sensors to be provided for monitoring other physical quantities, e.g. optical senors, heat sensors or the like. In such a case the alarm condition is expediently ascertained separately for each type of physical quantity, and the actual signals are each stored in separate sections of the first memory. Upon the occurrence of an alarm condition on the basis of the evaluation of one type of physical quantity, the 5 transmission of the actual values of the same type and/or different types of physical quantities into the second memory or memories occurs. Thus it is possible, for example, upon the automatic emission of an alarm signal on the basis of the parameters monitored by means of 10 acoustic signals, not only to cause a transmission of the acoustic actual values and a subsequent manual evaluation, but after the emission of the alarm, optical actual values can also be transferred into a corresponding second memory and be manually evaluated, 15 for example.

In particular if the individual components of an installation are distributed over a large area, the output signals of the sensors are expediently converted 20 by analog-to-digital converters into digital signals and then digitally transmitted, evaluated and stored. The digital signals of several sensors are expediently coordinated via a multiplexer and transmitted to the monitoring unit. By this it is possible to combine 25 locally adjacent sensors into groups and to save on transmission paths.

In the set-point memory not only set values representing the normal condition of the installation can be stored in 30 the set-point memory, but also set values representing determined error conditions, which are then used for comparison with the actual values. In this manner it is possible to rapidly identify frequently occurring error conditions, so that a safe evaluation is possible. In a learning phase of the monitoring system the knowledge obtained in the detailed examination on the significance of various actual signals, namely error condition or non- 5 error condition, can additionally be stored in the setpoint memory and used for future comparisons. In this manner it is Possible that a newly installed monitoring system collects such experimental values and stores them in the set-point memory, which consequently builds up a 10 routinely replenished library of signals which either express the normal condition or determined error conditions.

In the case of larger installations or also in the case 15 of installations which are not easily accessible,in accordance with another embodiment of the invention it is advantageous to construct the monitoring system in such a manner that the sensors of the installation are connected to a local monitoring unit in which a rough 20 evaluation of the signals is performed to detect an alarm condition as well as a subsequent detailed automatic and/or manual examination. In this case the monitoring unit is connected via remote transmission paths to a monitoring control station at a separate site in which 25 control and monitoring by a supervisor takes place far away from the local monitoring unit. This system is particularly expedient if, on account of its local distribution of the individual measuring sites, the installation is equipped with several local monitoring 30 units which are then connected via several remote transmission paths to a single monitoring control station. With such a configuration of the monitoring system, the remote transmission paths expediently consist of telephone transmission paths, in particular ISDN telephone transmission paths. To improve the transmission quality, the digitally transmitted signals an be coded according to an MPEG method, 30 that a couble-free transmission of the signal is possible even ith a small band width of the transmission paths.

Further advantageous embodiments of the invention can be gathered from the sub-claims.

The invention is explained in further detail below by means of a block diagram of the installation monitoring system.

15 In the block diagram acoustic sensors 1 to 5 are provided as an example, which are designed as air and/or structure-borne sound sensors and microphones. These sensors 1-5 are disposed at suitable sites on various installation parts. In the case of an installation in 20 which explosive substances are processed, e.g. in a gas distribution plant, an,--intrinsically explosiori-proof amplifier 12 and also an analog-to-digital (A/D) converter 13 is connected downstream from each of the sensors 1-5. The digital output signals of the analog- 25 to-digital converter 13 of the individual sensors 1-5 are then supplied to a multiplexer 17, and from there the coordinated signals are supplied via an input 14 to a local monitoring unit 20a.

30 Whereas the signals of the sensors 1-3 are supplied to the input 14 of the local monitoring unit 20a after coordination via the multiplexer 17, the block diagram also shows that two further sensors 4 and 5 are supplied via a further multiplexer 17 and an input 14 to another local monitoring unit 20b. This division of the sensors into groups 1-3 and 4 and 5, and the connection with two separated local monitoring units 20a and 20b is because 5 the sensors 5 and 5 are disposed, for example, at a more remote site of the installation than sensors 1-3. In such a case it is sensible on account of the greater distance to provide the monitoring systems 20a and 20b separately and to arrange them at separate sites.

The signal evaluation for a sensor 1-3 is now to be described below.

The actual signal inputted into the monitoring unit 20a 15 iscompared in a comparator 22 with a set-point signal, which is stored in a set-point memory 23. If this comparison results in a determined result, i.e. in a deviation from a set-point signal, for example, an alarm signal will appear at the output of the comparator 22 and 20 is sent to a computer 18. The actual signal of the respective channel that is at the input of the comparator 22 is simultaneously transmitted into a first memory 24, which has a limited memory capacity. It is designed, in particular, as a so-called FIFO memory or a ring memory 25 in which a limited number of actual values is stored, which can be fetched when required.

If a signal is now given to the computer 18 from the comparator 22 that an alarm or error condition has 30 occurred, the computer 18 causes either the entire content of the first memory 24 or at least the memorised actual values which are situated in temporal proximity to the signalling of the alarm to be transferred into a second memory 25, e.g. a hard disk memory. By this transfer it is now possible to investigate these actual signals more closely.

5 An examination of the actual signals transferred into the second memory 25 is initiated by the fact that they are played via a loudspeaker 27 to a supervisor of a monitoring control station 30 for monitoring. This supervisor may also cause this playing of the memorised 10 actual signals to take place several times, certain sections to be selected, or however for comparison the associated signals to be fetched from the set-point memory 23 and to be supplied via a change-over switch 26 to the loudspeaker 27. Similarly the system works via 15 the local monitoring unit 20b in connection with the sensors 4 and 5.

The installation monitoring system therefore works conveniently in two steps. In a first step, by a rough 20 checking of the actual values given by the sensors 1-5, as it were a temporary alarm signal is emitted, which draws the attention of the supervisor in the monitoring control station. The supervisor can now investigate the condition of the installation in closer detail by 25 fetching the stored actual values in time relationship to the instant of the raising of the alarm and in this case check whether the actual signals that resulted in the alarm being given actually belong to an abnormal condition of the installation or possibly are only caused 30 by environmental influences. The operator can also cause determined actual signals which occurred during such a subsequent evaluation to be inputted as additional set values into the set-point memory 23, i.e. a learning operation is performed in the monitoring system for improving the content of the signal library (set-point memory 23).

5 If in the present exemplified embodiment the sensors 1-5 are acoustic sensors, it is expedient that after an alarm is given after comparing these acoustic signals in the comparator 22 with set values of the setpoint memory 23, these acoustic actual signals, which are stored in the 10 f irst memory 24 and then in the second memory 25, are monitored by the supervisor for checking purposes. However, it is also possible to detect other physical parameters by corresponding sensors in the installation to be monitored and to process them in another evaluation 15 section of the monitoring unit 20a or 20b, to store them temporarily and then to transfer them into a second memory.

If an alarm condition is ascertained when monitoring 20 another physical parameter in the same manner, it is possible to input this alarm condition from the other monitoring section via an external input 9 into the computer 18 and to cause a manual checking operation by the supervisor. In other words, if an alarm condition is 25 given e.g. on the basis of monitoring optical signals, then by a corresponding signal at the external input 9 this can result in that acoustic actual signals, which are temporarily stored in the first memory 24, are transmitted into the second, permanent memory 25 in order 30 to monitor and to check the acoustic actual values.

Furthermore, in the described monitoring system another backward channel 28 is also provided, via which the supervisor can transmit backward signals to the individual monitoring sites of the installation. In the present case, for example, a loudspeaker 10 is associated with the monitoring site with the sensors 1- 3 and a 5 loudspeaker 11, which is connected via an explosion-proof amplifier 15 and a digital-to-analog converter 15 to the backward channel 28, is associated with the monitoring site with the sensors 4 and 5. By this the output signal of a sound generator 19 is transmitted to the loudspeaker 10 10 or 11. The sound source 19 is either supplied by a microphone 31 with sound signals, which are inputted e.g.

by the supervisor, or certain sound signals are transmitted from the computer 18, in order to check the action of these sound signals by means of the sensors 1-3 15 and respectively 4 and 5.

Even if the present invention was described in association with acoustic sensors 1-5 and the generation of corresponding sound signals, the sensors 1-6 may of 20 course also be of a different type and monitor other physical quantities. It is also shown in the block diagram that the two local monitoring units 20a and 20b as well as possible other monitoring units with correspondingly connected sensors (not shown) are 25 connected via remote transmission paths 32 with a monitoring control station 30. In thismonitoring control station 30 there is at least one supervisor, who communicates via corresponding operating elements (not shown) and at least via a microphone 31 and a loudspeaker 30 27 with the local monitoring units 20a and 20b etc. The monitoring control station 30 is locally separated from the individual monitoring units 20a, 20b, and transmission can occur over large distances by means of remote transmission paths 32. These remote transmission paths 32 are designed as ISDN telephone lines in the present example, which are connected via the ISDN units 21 and 29 respectively. To enable interference-free 5 transmission with high quality, even over long transmission paths with a small band width, as telephone lines normally are, the digitally available transmitted signals are coded and decoded in accordance with known MPEG coding methods.

Claims

1. An installation monitoring system, in which a plurality of sensor (1-5) conditions at various sites of 5 an installation are routinely monitored in one or more monitoring units (20a, 20b), the actual signals derived therefrom are compared with set signals stored in a setpoint memory (23) and in the event of deviations an alarm condition is signalled and/or the installation or 10 installation parts are shut down or switched off, characterised in that the actual signals are routinely stored via multiple channels in a first memory (24) and in the event of an alarm condition the actual signals occurring in a time interval surrounding the occurrence of 15 the alarm condition are transferred into a second memory (25) and are subjected to a detailed automatic examination and/or manual examination by a supervisor.

2. A monitoring system according to claim 1, 20 characterised in that the sensors (1-5) are air and/or structure-borne sound sensors which are disposed at various sites of the installation.

3. A monitoring system according to claim 2, 25 characterised in that the manual examination takes place by monitoring the stored signals.

4. A monitoring system according to any one of claims 1 3, characterised in that the first memory (24) is a memory 30 of limited capacity, which stores the actual signals of a limited time interval and is routinely overwritten by new actual signals, and in that the second memory (25) permanently stores the actual signals transmitted from the first 5 memory (24).

5. A monitoring System according to one of Claims 1-4, characterised in that the actual signals transferred into the second memory (25) are fetched and examined 10 by the supervisor and in that if necessary associated set signals are fetched and compared with the fetched actual signals.

15

6. A monitoring system according to one of Claims 1-5, characterised in that sensors (1-5) for monitoring various type of physical quantity are provided in the installation and in that the actual values of the sensors are 20 compared with corresponding stored set values for the detection of an alarm condition.

7. A monitoring system according to Claim 6, characterised in that the alarm condition is 25 determined separately for each type of physical quantity and the actual signals are each stored in separate sections of the first memory (24).

8. A monitoring system according to Claim 7, 30 characterised in that upon the occurrence of an alarm condition on the basis of the evaluation of one type of physical quantity, the transmission of the actual values of the same type and/or different types of physical quantities into the second memory or memories (25) takes place.

9. A monitoring system according to one of the 5 preceding Claims, characterised in that the output signals of the sensors (1-6) are converted by analog-to-digital converters (13) into digital signals and then digitally transmitted, evaluated and stored.

10. A monitoring system according to Claim 9, characterised in that the digital signals of several sensors (1-5) are coordinated via a multiplexer (17) and transmitted to the monitoring unit (20a, 20b).

11. A monitoring system according to one of the preceding Claims, characterised in that set values representing the normal condition of the installation as well as set 20 values representing certain error conditions are stored in the set-point memory (23) and are used for comparison with the actual values.

12. A monitoring system according to Claim 11, 25 characterised in that in a learning phase of the monitoring system the knowledge obtained in the detailed examination about the significance of various actual signals, namely error condition or non-error condition, are additionally stored in the 30 set-point memory (23) and are used for future comparisons.

13. A monitoring system according to one of the preceding Claims, characterised in that the set signals are stored in the set-point memory (23) as time signals.

14. A monitoring system according to one of Claims 1-12, characterised in that the set signals are stored in the set-point memory (23) as the parameter describing the time signal.

15. A monitoring system according to one of the preceding Claims, characterised in that a backward channel (28) is provided from the monitoring unit (20a, 20b) to the 15 individual installation sites in order to emit determined signals via loudspeakers (10, 11) for test purposes or instructions.

16. A monitoring system according to one or more of the 20 preceding Claims, cha.racterised in that the sensors (1-5) of the installation are connected to a local monitoring unit (20a, 20b) in which a rough evaluation of the signals takes place for the detection of an alarm 25 condition and also a subsequent detailed automatic and/or manual examination takes place, and in that the monitoring unit (20a, 20b) is connected via remote transmission paths (21, 29, 32) with a monitoring control station (30) in which 30 control and monitoring are performed by a supervisor.

17. A monitoring system according to Clams 15 and 16, characterised in that the backward channel leads from the monitoring control station (30) via the 5 remote transmission paths (21, 29,32) and the local monitoring unit (20a, 20b) to the installation site.

18. A monitoring system according to Claim 16 or 17, characterised in that several local monitoring units 10 (20a, 20b) are connected to a monitoring control station (30) via remote transmission paths (21, 29, 32).

19. A monitoring system according to one of Claims 16 15 18, characterised in that the remote transmission paths (21, 29, 32) are ISDN telephone transmission paths.

20. A monitoring system according to one of Claims 16 20 19, characterised in that the signals are coded via the remote transmission paths in accordance with the MPEG method.

25

21. A monitoring system according to one of the preceding Claims, characterised in that it is designed for monitoring gas-conveying installations and in that the sensors (1-5) are intrinsically 30 explosion-proof.

22. A monitoring system substantially as herein described with reference to the accompanying drawing.