Abstract:
Supervision of industrial plants can be improved by comparison and analysis of process information and network information. The comparison may be used to provide alarms and operator information for network-related or process device failures. The information may also be used to identify a cause of a failure. A method is described for supervising an industrial control system, including a plant network for supervision, a client/server network for server connection with workstations, and a control network connected to industrial controllers. The method comprises the steps of gathering process information, and gathering network information, and by comparing information provided by data communications network monitoring with process control information and using the result of the comparison to assist in determining a cause of a problem or possible problem in a process controlled of the industrial control system.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is a continuation of pending International patent application PCT/EP2008/050518 filed on Jan. 17, 2008 which designates the United States and claims priority from Swedish patent application 07000135-7 filed on Jan. 19, 2007, the content of which is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention concerns methods for monitoring and control of network information in an industrial plant. It comprises one or more techniques to facilitate commissioning and operation of a plant, and uses both network generated information and process information. 
       BACKGROUND OF THE INVENTION 
       [0003]    Industrial control systems are for instance applied in manufacturing and process industries, such as chemical plants, oil production or processing plants, refineries, pulp and paper mills, steel mills and automated factories. Industrial control systems are also widely used within the electrical power industry. Such industrial control systems have a large amount of network infrastructure, of which a major proportion can be based on Ethernet and TCP/IP technology. With such large data and control infrastructures there is an important requirement for an efficient supervision of the plant behaviour, and also for efficient supervision of the network infrastructure. 
       SUMMARY OF THE INVENTION 
       [0004]    The object of the present invention is to provide an industrial controller with a method and a means to combine process-related information with data communication network-related information from data network monitoring and/or supervision. This may be used for plant development both at commissioning and operational time. The improvement may also provide cause identification of failed process devices. An embodiment of the present invention provides an improvement to methods of network management for an industrial plant, both at commissioning and at operational times. 
         [0005]    According to an aspect of the invention a method is described for supervising an industrial control system, comprising a plant network for supervision, a client/server network for server connection with workstations, a control network connected to industrial controllers, said method comprising the steps of gathering process information, and gathering network information, and further by comparing information provided by data communications network monitoring with process control information and using the result of the comparison to assist in determining a cause of a problem or possible problem in a process controlled of the said industrial control system. 
         [0006]    According to an embodiment of the present invention a method is described for supervising an industrial control system, comprising a plant network for supervision, a client/server network for server connection with workstations, a control network connected to industrial controllers, said method comprising the steps of gathering process information, and gathering network information, and further by comparing information to determine a cause of a fault or possible fault wherein the information is gathered in real-time. 
         [0007]    According to another embodiment of the present invention a method is described for supervising an industrial control system, comprising a plant network for supervision, a client/server network for server connection with workstations, a control network connected to industrial controllers, said method comprising the steps of gathering process information, and gathering network information, and further by comparing information to determine a cause of a fault or possible fault wherein the process or process control information is gathered by means of a data server compatible with a standard for object linking or information exchange between distributed, mixed or un-homogenous systems. 
         [0008]    According to another embodiment of the present invention a method is described for supervising an industrial control system, comprising a plant network for supervision, a client/server network for server connection with workstations, a control network connected to industrial controllers, said method comprising the steps of gathering process information, and gathering network information, and further by comparing information to determine a cause of a fault or possible fault wherein the process or process control information is gathered by means of a data server compatible with OPC. 
         [0009]    According to another embodiment of the present invention a method is described for supervising an industrial control system, comprising a plant network for supervision, a client/server network for server connection with workstations, a control network connected to industrial controllers, said method comprising the steps of gathering process information, and gathering network information, and further by comparing information to determine a cause of a fault or possible fault wherein the data communications network monitoring information is gathered by means of a device and/or application compatible with SNMP (Simple Network Management Protocol). 
         [0010]    According to another embodiment of the present invention a method is described for supervising an industrial control system, comprising a plant network for supervision, a client/server network for server connection with workstations, a control network connected to industrial controllers, said method comprising the steps of gathering process information, and gathering network information, and further by comparing information provided by data communications network monitoring with process control information and using the result of the comparison to assist in determining a cause of a problem or possible problem in a process controlled by a process controller in the said industrial control system, and by comparing the combined information gathered according to SNMP and OPC in order to assist in determining the cause of the fault or the possible fault. 
         [0011]    According to another embodiment of the present invention a method is described for supervising an industrial control system, wherein process information is compared to network information and recording an information, and/or an event, and/or an alarm in the said industrial control system when the said process information indicates a problem, but the said network monitoring information does not indicate a problem. 
         [0012]    According to another embodiment of the present invention a method is described for supervising an industrial control system, wherein process information is compared to network information and by checking, on receipt of a faulty status for a process device that the process logic is as expected, and checking on receiving confirmation that the process logic is as expected all network devices the process device is connected to, and by generating an alarm for the process logic of the process device or the process device if all the network devices show a normal status; or else by generating an alarm if some of the network devices show a faulty status for the faulty network devices. 
         [0013]    According to another embodiment of the present invention a method is described for supervising an industrial control system, wherein process information is compared to network information and by identifying one or more persons responsible for the controlled process and by sending information based on a copy of the recorded information to one or more of them. 
         [0014]    According to another aspect of the present invention, an industrial control system is described comprising a plant network for supervision, a client/server network for server connection with workstations, a control network connected to industrial controllers, said system comprising means for gathering process information, and gathering network information, wherein the system further comprises network isolation means for segregating the networks and one or more applications means for comparing information provided by data communications network monitoring with process control information and using the result of the comparison to assist in determining a cause of a problem or possible problem in a process controlled of the said industrial control system. 
         [0015]    According to another aspect of the present invention, an industrial control system is described comprising a plant network for supervision, a client/server network for server connection with workstations, a control network connected to industrial controllers, said system comprising means for gathering process information, and gathering network information, wherein the system further comprises at least one data server means compatible with OPC. 
         [0016]    According to another aspect of the present invention, an industrial control system is described comprising a plant network for supervision, a client/server network for server connection with workstations, a control network connected to industrial controllers, said system comprising means for gathering process information, and gathering network information, wherein the system further comprises means for gathering data communications network monitoring information comprising a device, application or agent compatible with SNMP (Simple Network Management Protocol). 
         [0017]    According to another aspect of the present invention, an industrial control system is described comprising a plant network for supervision, a client/server network for server connection with workstations, a control network connected to industrial controllers, said system comprising means for gathering process information, and gathering network information, wherein the system further comprises means for comparing the combined information gathered according to SNMP and OPC. 
         [0018]    A principal advantage of the present invention is that information from the industrial process or equipment may be combined with information from the data communication networks and provide improved diagnostic capabilities in industrial plants and processes. Another advantage is that the functionality offered by the existing network management tools is extended by the present invention so filling an existing gap in condition detection and reporting. This provides improved information and facilitate will help both plant operation both at commissioning and operational time by facilitating detection of failed or failing process devices. The additional scope provides information to perform the cause identification of some failed or failing process devices. This improvement is also of benefit during plant development or upgrades, again both during commissioning and during subsequent normal operation. 
         [0019]    Additional advantages include that the diagnostic functionality for existing industrial controller devices and other networked process devices is improved, without additional hardware or configuration changes. The methods involved may also be implemented in a user friendly way. 
         [0020]    In a preferred embodiment of the methods of the invention one or more methods may be carried out by a computing device comprising one or more microprocessor units or computers. The control unit(s) comprises memory means such for storing one or more computer programs for carrying out the improved methods. Preferably such computer program contains instructions for the processor to perform the method as mentioned above and described in more detail below. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    The present invention will be described in more detail in connection with the enclosed schematic drawings wherein: 
           [0022]      FIG. 1  shows a detailed view of the combination among process and network information, 
           [0023]      FIG. 2  shows a view about how the process and network information are being combined and where the results are displayed on a supervision station for an industrial plant, 
           [0024]      FIG. 3  shows a simplified example of network devices interconnection and the propagation of process and network information to a supervision station from an industrial controller, 
           [0025]      FIG. 4  shows a schematic overview of the network and relevant equipment to be used in the industrial plant, 
           [0026]      FIG. 5  shows a flowchart of an algorithm for comparison and combination of data for a process control application and from a network monitoring application, 
           [0027]      FIG. 6  shows a simplified HMI (Human Machine Interface) for an application for process control or supervision of process control devices in an industrial control system, 
           [0028]      FIG. 7  shows a simplified HMI (Human Machine Interface) for an application for monitoring states of a data communications network in an industrial control system. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0029]      FIG. 3  shows a simplified and general view over an industrial plant control system network  1 , containing a plant network  2  for supervision with workstations  15 , a client/server network  3  for server connection with workstations  15 , a control network  4  for connection to industrial controllers  18  and a field network  5  for the connection of remote I/O devices  19  and or proxy devices  20 . Network isolation devices  8 ,  8 ′ are used to segregate the networks. The plant network  2  may be connected via a suitable firewall  11  to a public network such as the Internet  14 . 
         [0030]      FIG. 1  shows an industrial plant network as a block diagram. The plant network may be considered as a mixed or unhomogenous network in that it may include two or more networks or sub-networks connected together and running with a different protocol or a different set of protocols. The plant network of  FIG. 1  for example contains a client-server network  3  and a control network  4 , separated by a network isolation device, a SNMP enabled switch or industrial router  9 , an industrial controller  20  and an Ethernet enabled remote I/O device  22 . In one development remote I/O device  22  may optionally be an Ethernet enabled device arranged with an equivalent of a Ethernet link or network for high speed transmission of up to 100 Mbits/or more, complying with IEEE standards such as IEEE 802 or later. SNMP network information can be gathered from the industrial controller supervision station  15  on 2, from the switch  9  and from the network isolation device  8 . Process information is gathered from the industrial controller  20  and from the device. Preferably the industrial controller is an advanced industrial controller such as of the AC800M type or later, supplied by ABB. 
         [0031]      FIG. 1  shows schematically tools within a supervision and communication system of an industrial plant an industrial controller used either for handling or processing process information  28 , or used for handling or processing network information  29 , according to an embodiment of the invention. Process information  28  is used within a process control software developers package such as ControlBuilder. Network information is consumed within a network monitoring application such as a PNSM (PC, Network and Software monitoring) tool. Both tools may communicate with the alarms system and with the information display system by means of OPC (OLE for Process Control) and by means of the underlying process control system software architecture. 
         [0032]      FIG. 2  shows a general view over a schematic format or layout for the proposed algorithm of comparison of network information  290  with process information  280 , taking into account the object type representations for process devices and for network devices. It is to be mentioned that in the object type for a process device, a list of all its interconnections to network devices is given. 
         [0033]      FIG. 5  shows a flowchart of a combination algorithm, where the process values concerning the status of a process device are compared with the network values from the network devices to which the process device is connected to. If the process value from a process device shows a faulty status, then the process logic, installed on the process device, must be checked. This check must be followed by another one, which concerns all the network devices the respective process device is connected to. If all the network devices show a correct status, then the faulty status shown on the process device is most likely due to the installed process logic on the respective device and an alarm should be issued and the error repaired. If some of the network devices the process device is connected to show a faulty status, then the faulty status the process device was showing may be due to the faulty network devices and an alarm should be issued and the error repaired. 
         [0034]    These steps of the algorithm may be followed a check of the Ethernet interface of the process device, in order to insure the faulty status is not related to this situation. In case this shows faulty, an alarm should be issued and the error repaired. 
         [0035]    The algorithm is then run until there are no more faulty status&#39; reported. The algorithm would be as follows: 
         [0000]    
       
         
               
               
             
               
               
             
               
               
             
               
               
             
               
               
             
               
               
             
               
               
             
               
               
             
               
               
             
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 Until (no more NOT OK status reported) 
               
             
          
           
               
                   
                 If (process_device.process_value.status=NOT OK 
               
             
          
           
               
                   
                 Check process logic on process device 
               
             
          
           
               
                   
                 If (for all connected (network_device.network_value)=OK) 
               
             
          
           
               
                   
                 Issue_alarm (process device failure) 
               
             
          
           
               
                   
                 else (for some of connected 
               
             
          
           
               
                   
                 (network_device.network_value)=NOT OK 
               
             
          
           
               
                   
                 Issue_alarm (network related failure) 
               
             
          
           
               
                   
                 Check process_device Ethernet interface on process device 
               
               
                   
                 If (process_device.Ethernet_interface=NOT_OK) 
               
             
          
           
               
                   
                 Issue_alarm (network interface failure) 
               
               
                   
                   
               
             
          
         
       
     
       Test Example 
       [0036]    In the following example network and control information were gathered for a control device, which in this case was an ABB AC800M controller, installed in a test installation. Network information was also gathered for the connections of this controller to a network switch, which is a network device, that is, a device for regulating data communications over a network. 
         [0037]    The control device repeatedly reported Bad network status at two-hourly intervals and at each time every two hours the network device reported high bandwidth usage for the port to which the said control device was connected. 
         [0038]    During this time the control information concerning the control device displayed a good status. This particular control device is redundant and therefore it needs two connections to the network device, see  FIG. 6 .  FIG. 6  shows a simplified graphic user interface of a SNMP network management application monitoring a network and running, for example, on a supervision station for an industrial plant. Such an interface may have been constructed using a SNMP network management application mentioned above. The figure shows a first network device  18 ′ at a first URL address and a second and redundant network device  18 ″ with a second URL address. The first network device is connected to six ports indicated as  31 ,  32 ,  34 ,  33 ,  36  and  35 . Ports  34 ,  33 , are displayed with a different appearance from ports  31 ,  32 ,  35 ,  36  signifying a non-normal state. These ports are connected to a redundant controller shown as  456 F&amp;G  41  and  456 F&amp;G(r)  42 . 
         [0039]    Three process devices, shown here as HVAC,  123 F&amp;G and  123 F&amp;G(r) on the normal ports  31 ,  32 ,  35 ,  36  are each showing normal Status at  40 ,  43 ,  44  respectively for the process devices. However one first process control device  456 F&amp;G is showing a Bad Network status  41 , indicated as a dotted background to the respective image or symbol object of the process control information application. The second and redundant network device  18 ″ for the same control function is also showing a Bad Network Status  42  on a second device image object display. 
         [0040]      FIG. 7  shows a simplified graphic user interface of a network management application monitoring the data communication network.  FIG. 7  shows the bidirectional bandwidth usage for two ports  53 ,  57 , ie port  38  and port  37 . The figure shows a plurality of interconnected process and network devices  19 . The GUI shows the bidirectional bandwidth usage among a process device  52  and a network device  51 . Data is displayed for the two devices on the GUI. The GUI displays for example data concerning bandwidth usage for the ports  37  and  38  associated with the two selected objects. The data includes bandwidth diagrams  54  and  55 . It can be seen that the first bandwidth usage  54  (direction from port  37  to port  38 ) shows an excessive bandwidth usage periodically and that the second diagram  55  (direction from port  38  to port  37 ) shows a continuous and relatively low use of bandwidth on the network. These values are obtained using SNMP information, provided by the SNMP agents on the network device  51 . 
         [0041]    During the time the test investigation was taking place the controller  456  F&amp;G and  456  F&amp;G(R)  41  and  42  of  FIG. 6  was restarted. After finishing the boot sequence, the redundant part ( 456  F&amp;G (R)) had a complete hardware failure. Thus the excessive bandwidth usage by one of the two redundant control devices was detectable by means of the SNMP network monitoring of the network devices connected into the data network. 
         [0042]    Thus by comparing in the test example above certain information from the process control system, Bad network status, with information from the SNMP network monitoring application for the same devices, in this case high bandwidth usage on one port, a fault signal is derivable from network data about one of the two redundant devices. 
         [0043]    SNMP is a protocol for network monitoring and reporting that operates at the application level using TCP/IP transport protocols. It comprises agent software and management software in a client-server approach. The management software runs at least a monitoring function which uses data accessed by means of the agents running in each of the nodes of the network so configured. There are a plurality of public domain SNMP tools available as well as commercially distributed SNMP tools and packages from such well-known software companies as Cisco, Sun, Hewlett Packard and Microsoft. Network monitoring and reporting tools using a protocol which does not use transport level protocols, such as the TCP/UDP/IP suite, or which depend on protocols other than SNMP or in addition to SNMP, may also be used to practise the invention. 
         [0044]    Preferably the industrial plant network is arranged with one or more data servers compatible with OLE for exchanging information, for reading, recording and/or transmitting information, and in particular for process information and plant related data. One or more data servers compatible with other standards such as COM/DCOM (Distributed Component Object Model) or DDE (Dynamic Data Exchange) or other industrial quality standards for information exchange or object linking across distributed systems may be used instead of, or as well as, an OLE server. There are other standards available for object linking and/or information exchange between mixed or unhomogenous systems, which include Common Object Request Broker Architecture (CORBA) and OpenDoc, sponsored through Component Integration Laboratories (CI Labs). Other protocols may be utilized in future, such as Java RMI (Remote Method Invocation). 
         [0045]    Methods of the invention may be supervised, controlled or carried out by one or more computer programs. One or more microprocessors (or processors or computers) comprise a central processing unit CPU connected to or comprised robot control unit described, which processors, PLCs or computers perform the steps of the methods according to one or more aspects of the invention, as described for example for operating or controlling processes and equipment in an industrial control system and with reference to the algorithm as described and shown in  FIG. 5 . It is to be understood that the computer programs for carrying out methods according to the invention may also be run on one or more general purpose industrial microprocessors or PLCs or computers instead of one or more specially adapted computers or processors. 
         [0046]    The computer program comprises computer program code elements or software code portions that make the computer or processor perform the methods using equations, algorithms, data, stored values, calculations, synchronisations and the like for the methods previously described, and for example in relation to the algorithm of  FIG. 5 . A part of the program may be stored in a processor as above, but also in a ROM, RAM, PROM, EPROM or EEPROM chip or similar memory means. The or some of the programs in part or in whole may also be stored locally (or centrally) on, or in, a memory storage device of a control system, as well as on other suitable computer readable medium such as a magnetic disk, CD-ROM or DVD disk, hard disk, magneto-optical memory storage means, in volatile memory, in flash memory, as firmware, or stored on a data server. Other known and suitable media, including removable memory media such as a memory stick and other removable flash memories, hard drives etc. may also be used. The program may also in part be supplied or updated from a data network, including a public network such as the Internet. 
         [0047]    It should be noted that while the above describes exemplifying embodiments of the invention, there are several variations and modifications which may be made to the disclosed solution without departing from the scope of the present invention as defined in the appended claims.