SE1400412A1 - A remote server and a Remote Service Device configured for data communication between the remote server and local industrial devices - Google Patents

Description

15 20 25 30 provide effective capacity for a large number of devices for which requirement for service may vary in an unpredictable fashion. In an example from another technical field, that of operating systems for personal computers, the operating system Win 95 (Windows 95) introduced centralised automated software updates for software running on computers of individual users. US 5,845,077 entitled Method and system for identifying and obtaining computer software from a remote computer, assigned to Microsoft Corporation, was filed first in 1995 and describes the methods and systems used with Windows 95.

The software company Microsoft provided an update service to which pc users could dial-up to using a telephone modem or otherwise connect via the Internet. The update service had servers that hosted applications which catalogued a user's configuration of their Windows 95 operating system, determined which update or patch was required, and, subject to user agreement, then downloaded the identified patch for installation on the user computer. Since that time Variations on this kind of software updating system and method have become very widely used in the field of consumer software.

An industrial device at a location in the field will routinely establish a communication with a remote server.

Allowing only a mode of dial-out or outbound initiation is normally done so that the end user/customer does not need to open their firewalls for inbound connections.

This is to avoid a risk of incoming traffic that could include malicious, nuisance or criminal intrusion in a device or a system the device is connected to. 10 15 20 25 30 Thus for the purpose of monitoring industrial equipment a device in the field can establish communications with a remote server provided for that purpose. The remote server, typically a device manufacturer, can arranged to handle monitoring of the device, and receive data on some basis, which may typically be a cyclic basis. Monitoring local field devices may be carried out satisfactorily when the remote server(s) can meet the capacity demands of local devices in the field.

When troubleshooting problems remotely some additional or fresh data may be needed. To reduce a peak load created by a number or excessive number of simultaneous connections on a remote server, the service device usually polls the remote server cyclically to check if there are any new commands to receive or download. The time taken by one or more devices in the field to respond a request for fresh data, the response time, is therefore affected at least by the polling frequency of the device, and also by parameters such as the number of concurrent connections supported by the server. If scheduling to poll for commands is done by devices in the field, and if the device clocks are synchronized, then the server will most likely get a burst of connections at the same time.

Thus cyclic polling by the devices being monitored can result in bursts of an excessive number of devices attempting to connect at the same time (for example within milliseconds if Simple Network Time Protocol (SNTP) is used), which may result in an overload or in a Denial of Service (DOS) condition on the server side.

There is therefore a need for improvement on this situation. 10 15 20 25 30 SUMARY The present invention addresses the above situation. The invention is therefore directed towards solving the problem by providing more optimal scheduling for communication between a remote server and one or more local field devices.

This object is according to a first aspect of the invention is solved by a remote server configured for receiving data communication from a local field device in a local installation or process, where the local field device is connected to a Remote Service Device configured for connecting the local field device to the remote server, wherein the remote server comprises a computer or processor and computer program instructions for: balancing a data communication load on the remote server to optimise use of server resources by a plurality of Remote Service Devices and computer program instructions for sending commands to the Remote Service Device for collection of data from the local field device.

In machine-to-machine (M2M) systems or solutions there are a lot of devices that connect to remote servers. When many devices connect at the same time this will use up a lot of the server resources for example, a large number of connections and/or use of server memory storage and/or server processing power. Problems have arisen when scheduling to poll for commands has been run from the device in the field, particularly when device clocks are synchronized, the server(s) have received bursts of connections and connection attempts at the same time. For example if every device polls for commands every minute the server will get all the connection attempts at the 10 15 20 25 30 same time, e.g. within milliseconds if SNTP is used. In this description a local field device is described as an example of an industrial device. However data collection according to an embodiment may also be carried out for an industrial device that is not a local field device or other component in a traditional industrial process controlled by an industrial control system. The industrial device may a type of device that is connected to the remote server and not necessarily connected to an industrial control system. Some examples of industrial devices which are not usually described by the term local robot controller, field devices are: tool or equipment mounted on a robot, voltage converter, transformer, distribution transformer, switch or breaker, soft starter, electric motor, electricity use meter, solar panel, solar panel inverter, battery monitor, electrical charging station monitor.

According to an embodiment the function of controlling polling of the server is moved from a device in the field to the remote server. Accordingly the remote server is configured with a functionality which can balance the number of connected devices by, for example, making intelligent decisions based on measurements and calculations to select which device should disconnect and (wait for how long one or more devices should back off before attempting a re-connect) before connecting again.

According to a second aspect of the present invention a Remote Service Device is provided which is configuredfor communication with a remote server (l) and connected to an industrial device or a local field device and configured for connecting the local field device to the remote server. 10 15 20 25 According to a third aspect of the present invention a method is provided for configuring a remote server (1) for receiving data communication from a local field device by means of a Remote Service Device configured for connecting the local field device to the remote server.

According to a fourth aspect of the present invention a first computer program product is provided for carrying out one or more functions of a remote server which comprises computer instructions or computer-executable components for causing a device to perform the steps of the first aspect presented herein, when the computer instructions are run on a computer or processor.

According to the fourth aspect of the present invention a second computer program product is provided for carrying out one or more functions of a Remote Service Device which comprises computer instructions or computer- executable components for causing a device to perform the steps of the second aspect presented herein, when the computer instructions are run on a computer or processor.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to a/an/the element, apparatus, component, means, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, etc., component, means, unless explicitly stated otherwise. Moreover, any step in a method need not necessarily have to be carried out in the presented order, unless explicitly stated otherwise. 10 15 20 25 30 BRIEF DESCRIPTION OF THE DRAWINGS The specific embodiments of the inventive concept will now be described, by way of example, with reference to the accompanying drawings, in which; Fig. 1 shows a schematic diagram of a remote server configured for receiving data communication from an industrial device or local field device, using a wide area network, e.g., Internet, according to an embodiment of a first aspect of the invention; and Fig. 2a is a schematic diagram of the field devices in an industrial installation according to an embodiment of the invention of Figure 1, showing in particular a configuration of an industrial device in the form of one field device at a first location configured to practise the invention; Fig. 2b is a similar schematic diagram of local field devices in an industrial process according to an embodiment of the invention of Figure 1 and showing in particular a plurality of industrial devices in the form of local field devices at a second location configured to practise the invention; Fig. 3 is a schematic diagram of the remote server according to the invention of Figure 1 and showing in particular a configuration for parts of a computer or processor comprised in the remote server; Fig. 4 is a flowchart of a third aspect of the invention of Figure 1 which is a method of configuring a remote server for receiving data communication from an industrial device in the form of a local field device in an industrial installation or process, showing in particular a method or process for determining whether or not a first field device shall be allowed to connect or 10 15 20 25 30 re-connect at any time; and Fig. 5 is a flowchart of a related method showing in particular a method or process for determining an Optimum number of second or other industrial devices in the form of local field devices to remain connected to the remote server at any one time and/or disconnecting one or more; Fig. 6 is a schematic diagram of according to a fourth aspect of the invention, a data carrier with computer program instructions or computer program code, in the form of a CD-ROM disc, for performing the steps of the method according to the third aspect of the invention of Fig. 1; Figure 7 is a schematic diagram of part of a Remote Service Device according to an embodiment of the second aspect of the invention of Figure 1 and showing in particular a configuration for parts of the Remote Service Device; Figure 8 is a flowchart of an embodiment of the third aspect of the invention of Figure l, the method, and showing in particular a method or process with which the remote server may instruct one, presently connected Remote Service Device, to send communications or one or more commands to other, and currently not-connected, Remote Service Devices.

DETAILED DESCRIPTION The inventive concept will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplifying embodiments are shown. The inventive concept may, however, be embodied in many different forms and should not be construed as limited to these the embodiments set forth herein; rather, 10 15 20 25 30 embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concept to those skilled in the art. Like numbers refer to like elements throughout the description.

The present disclosure relates in a first aspect of the invention to a remote server configured for receiving data communication from a local industrial device, for example a local field device, in a local industrial installation or process. The local field device may be monitored and controlled by an industrial control system.

As a part of the configuration of the inventive remote server, said local field device is connected to the remote server by means of a Remote Service Device. The invention may advantageously be utilised in an industrial process setting. An industrial process is to be understood to mean a procedure that involves chemical, electrical or mechanical steps to aid in manufacturing, production, power generation, fabrication, or refining.

Examples of such industrial processes are processes relating to the production or refining of oil and gas, the petrochemical industry, power generation, power transmission, power distribution, metals and mining, chemical industry, pulp and paper, or automation in e.g. the manufacturing industry or food industry. Other applications than industrial process applications are also envisaged.

As mentioned above, a local field device is described in this description in detail as an example of an industrial device. Data may also be collected from an industrial device in another type of installation. The industrial device may be another type of device that is to be 10 15 20 25 30 10 connected to the remote server. Other examples of industrial devices are: robot controller, tool or equipment mounted on a robot, electric motor, soft starter, voltage converter. In an industrial setting or a utility setting an industrial device may be any of: switch or breaker, transformer, distribution transformer, electricity use meter. In a commercial building or a residential building an industrial device may be any of: electricity use meter, solar panel, solar panel inverter or control unit, battery monitor, electrical charging station monitor.

Fig. 1 depicts an example of a remote server configured for communication with one or more industrial devices, in this example local field devices, in which the wired or wireless communication is facilitated by at least one Remote Service Device. The figure shows a remote server 1 which is connected to several Remote Service Devices (RSDs) 5a-5d located locally in the field. The remote server 1 is located at a distant or central location 6b and connected 2 with a computer 3 at location 6a which is used for monitoring, maintenance and analysis of data collected from field devices at a plurality of locations 7a, 7b. The remote server 1 is also arranged with suitable security measures such as a Firewall 4 to prevent unauthorised access to the remote server.

The remote server 1 is arranged with one or more databases and lines of communication via private local networks, wired or wireless area networks lla and/or wide area networks or public networks such as the Internet 10.

The remote server 1 is arranged configured for communication with a first field device 9a at A, a first location 7a, via a Remote Service Device Sa. The remote 10 15 20 25 30 ll server 1 is also configured for communication with other field devices 9b-9d, arranged in other systems, at B which is a second, separate location 7b. The local systems are protected by suitable security measures or devices, such as a Firewall 14 arranged between Remote Service Devices such as 5b, 5c and external networks, in particular any non-private networks connected to public networks such as the Internet 10.

Figures 2a and 2b show a number of field devices in one or more industrial processes connected to an industrial control system. An industrial process may be monitored through one or more process monitoring computers, which communicate with a server handling monitoring and control of the process. This control system and the process will be described in detail with respect to a process 32 at location A; and subsequently in relation to Fig. 2b a control system at location B, which shows a second process 42 at the second location B, will only be described summarily.

Figure 2a shows an industrial process which is at a first location A, reference 7a in Fig. 1. The figure shows an industrial control system 20, comprising two operator workstation 18, 19, a first data bus D1 a system server 16, a system database 17 and a second data bus D2. Four field devices 9a, 26, 28, 30 are shown as being connected to the control system 20 at location A. The process control system or industrial control system 20 in relation to process 32 at location A therefore includes a number of process monitoring computers 18 and 19. These computers may here also be considered to form operator terminals and are connected to a first data bus D1.

Similar functions of monitoring and control at 18, 19 may 10 15 20 25 30 12 be carried out on the remote computer 3, as well as other more specific monitoring and control functions provided remotely. There is also a gateway 27 connected to this first data bus Dl, which gateway 27 is connected to at least one wireless network WN. The wireless network WN may be a local network, such as a wireless local area network (WLAN). It may be a wireless network compatible with a protocol such as WirelessHART or an ISA 100 standard such as ISA l00.l1a or later. The network may be configured as a wireless mesh network. It may also be a a network with a number of Bluetooth network, i.e. interconnected Bluetooth nodes. Other wireless standards that may be used on the wide area network side are WiFi, Or GPRS/3G, WiMax, 4G and so on.

There is furthermore a second data bus D2 and between the first and second data busses Dl and D2 there are connected a system server 16 providing control and protection of the process 32 and a system database 17 for the industrial control system 20 where data relating to control and protection of the process 32 is stored. Such data relating to control and protection may here comprise process data such as measurements made in the process and control commands, while data relating to protection may comprise alarm and event data as well as data based on which alarms and events can be generated.

To the second data bus D2 there is furthermore connected the field devices 9a, 26, 28 and 30 previously mentioned.

These further devices 9a, 26, 28 and 30 are field devices, which are devices that are interfaces to the process being controlled. A field device is typically an 10 15 20 25 30 13 interface via which measurements of the process 32 are made and to which control commands are given. Because of this the field devices are furthermore process control objects. In one variation of the invention a first field device is a first process control object 9a, for example a motor, and the second field device is a second process control object 26, for example a pump, the third is an actuator 28 powering a valve and the fourth process object 30 is a temperature sensor. One field device in process 32, first process object 9a the motor, is also arranged connected to Remote Service Device 5a which is configured for communication between the field device 9a and the remote server 1 of Fig. 1. In other words, a motor in process 32 at location A is connected and configured via Remote Service Device 5a connected to field device 9a for remote monitoring, analysis and maintenance with a remote computer 3 by means of communication established by the remote server 1 and the Remote Service Device 5a. Put another way, the remote server 1 establishes communication between Remote Service device(s) and a remote computer 3, which is used to carry out the monitoring, analysis and maintenance functions on at least one process 32, 42 at at least one location A, B using the data and measurements communicated from the local field devices 9a-d so monitored.

Figure 2b shows a similar process 42 at a second location B, reference number 7b in fig. 1, controlled by an industrial control system 40. Similarly to Figure 2a, in Figure 2b only four field devices are shown as connected to the second process 42 at location B. However it will be realised that more than 4, many more than 4 or fewer than four devices may be connected and supervised for the process 32, 42 at either location A or B. The four field 10 15 20 25 30 14 devices 24, 9b, 9c and 9d at location B may represent the same examples given in respect of Fig 2a, namely: a first process control object 24, for example a motor; a second field device being a second process control object 9b, for example a pump; the third field device may be an actuator 9c powering a valve and the fourth process object 9d may be a temperature sensor. In the process 42, three field devices 9b-9d are each arranged connected to a respective Remote Service Device 5b-5d. Each Remote Service Device 5b-5d is configured for communication between each of the respective field devices 9b-9d and the remote server 1 of Fig. 1. Thus there are three local field devices in second process 42 at location B: a pump is configured via Remote Service Device 9b, an actuator powering a valve is configured via Remote Service Device 9c and a temperature sensor is configured via Remote Service Device 9d and all three local field devices 9b-d are configured and connected for remote monitoring, analysis and maintenance with a remote computer 3 by means of communication established by the remote server l and the Remote Service Devices 5b-d.

The local field device, or any other industrial device, may not be connected to an industrial control system. In other words, data may be collected and sent to the remote server using an embodiment of the invention from an industrial device which is not connected to or monitored by an industrial control system. For example from a robot or robot controller, tool or equipment mounted on a robot. In another installation data may be collected from an electric motor, soft starter, or a voltage converter.

In an industrial setting or a utility setting data may be collected from an industrial device such as a: transformer, distribution transformer, switch or breaker, 10 15 20 25 30 15 electricity use meter. Also in a commercial building or a residential building data may be collected from an industrial device such as az electricity use meter, solar panel, solar panel inverter or control unit, battery monitor, electrical charging station monitor.

Fig. 3 shows a block schematic of a parts of a computer or processor comprised in the remote server 1 shown in Fig.1. The schematic of the computer or processor shows a processor 67 or processor core, a memory device 65 used for temporary memory storage by the processor, a memory storage device 58 for permanent or non-transitory storage of data, and transmitter/receiver 69 for wired or wireless communication via private and or public networks including the internet 10. The remote server 1 is also arranged with a wired and/or wireless connection 2 to a (remote) computer 3 at location 6a which is used to carry out the monitoring, analysis and maintenance functions on at least one process 32, 42 at at least one location A, B using the data and measurements communicated from the local field devices 9a-d so monitored at the or each location. The remote computer 3 similarly carries out monitoring, analysis and maintenance functions using the data and measurements communicated from industrial devices located at other installations such as utility sites and commercial or residential buildings.

According to the aspect of the invention shown in Figure 1, a number of Remote Service Devices (RSDs) are arranged configured to provide communication between the remote server 1 and field devices in one or more processes 32, 42. All of the RSDs normally try to keep a persistent 10 15 20 25 16 connection to the remote server. The advantage of this is that the remote server 1 can then send a command instantly to a RSD with no delay. For example a monitoring task may require that the Remote Service Device sends more data from a specified industrial device such as a local field device during a given period than is currently collected. In this case commands are sent by the remote server to the RSD specifying, typically, which data shall be collected, a sampling interval and a time period. Similarly, a command may be sent to a RSD that it shall turn itself off, for a given time period or for given conditions. Other commands to carry out service or maintenance functions on the RSD may be sent. For example, the remote server may send commands and/or data to one or more RSDs in order to carry out an update of software or of firmware on the RSD or RSDs.

The remote server may send one or more commands comprising any of: -collect data according to a new rule or schedule; -receive data and update information stored on the RSD; -receive and update software stored on the RSD -receive and update a firmware of the RSD -receive data and change a parameter on a local field device, -receive a new default value for a back-off time, update and/or store the new default value, and forward it to other RSDs if also so instructed. 10 15 20 25 30 17 At start up, a RSD creates a persistent connection to the remote server 1. The RSD transmits data from the field device, for example, according to a cycle time. If the RSD detects a disconnection from remote server 1 it will reconnect after a predefined or random default time (between retries). The remote server 1 may order a RSD to back off for a certain time, that is, it may send to the RSD a command telling it to disconnect and wait for a time before re-connecting. This may be for a specific time, a default time or, a by other means predetermined time, it may be one or more times per day; it may be of the order of seconds or minutes.

A remote server may serve remotely a very large number of local field devices, and from time to time the number of connections the remote server can handle, or the number of server requests that the server can handle at any one time, may be exceeded. When the Remote Server detects that it is running out of resources (e.g., the number of concurrent connections reach a limit) it may determine that a first threshold for resources has been reached. In one embodiment the server will check the statistics of the connected RSDs and determine which one or more RSDS should be ordered to disconnect and for how long. In another embodiment and in extreme conditions the server may choose to disconnect one or more RSDs without sending any additional information to the RSDs such as, for example, a specific back off time.

A “pool” of connections can be maintained in a way similar to the way an intelligent memory cache is used.

For example with the server predicting, based on statistics for the connected RSDs, which RSD devices are 10 15 20 25 18 more likely to be sent a command and keeping those identified RSDs connected.

Figure 4 is a flowchart of a third aspect of the invention of Figure 1, a method of configuring a remote server for establishing communication between a remote computer and a local field device in a local industrial installation or process. Fig. 4 comprises at least one of the steps of: 42 remote server 1 detects a connection or re-connection attempt by a first RSD 5a 44 Comparison: Are the resources of remote server 1 below a first threshold? If No 45 connect to RSD 5a If Yes, then: 46 Retrieve connection statistics for other, connected RSDs 5b-d 48 Calculate how many of the other connected RSDs 5b-d may need to be disconnected, and for what length of time 49 Calculate a back-off time for the first RSD 5a 50 Send the calculated back-off time to the first RSD 5a When the remote server 1 detects that it is running out of resources (e.g., the number of concurrent connections reach a limit and/or the number of server requests that the server can handle at any one time) and reached a first threshold it may carry out a procedure to optimise the number of connections as previously described. Other measures of resource use by the remote server 1 may also 10 15 20 25 19 be monitored such as processing load for handling polled data, processing load for sending commands to a group of RSDs on one network or on a plurality of networks. The remote server will also check the statistics of the connected RSDs and determine which one or more should be ordered to disconnect and for how long. The server may for example predict, based on statistics for the connected RSDs under a previous time period, which RSD devices are more likely to be sent a command in a coming time period, and keep those latter and identified RSDs connected by storing a value for an RSD or eg adjusting a connection or dis-connection priority for one or more RSDs. Under extreme conditions the server may choose to disconnect one or more RSDs without any additional information being sent 54 to the RSD(s).

Fig. 5 is a flowchart of a related method showing in particular a method or process for determining an optimum number of second or other local field devices to remain connected to the remote server at any one time, and comprises at least one of the steps of: 48 Calculate how many of the other connected RSDs Sb-d may need to be disconnected, and for what length of time 52 Calculate, for the number of other connected RSDs 5b- d, what length of time each one needs to be disconnected 54 (Optional step) Disconnect at least one of the other connected RSDs 5b-d without any back-off message 56 Communicate the back-off time calculated at 52 to the at least one RSD that is to be dis-connected and disconnect it / them. 10 15 20 25 30 20 In this way the remote server 1 may balance the number of Remote Service Devices connected at any one time and make advantageous estimates for which of the currently- connected Remote Service Device(s) should be disconnected; and also make an estimate of for how long a particular Remote Service Device should wait before attempting re-connection. This leads to a more optimal use of remote server 1, with response times that are reduced to some extent and a more effective use of the resources installed in the remote monitoring system.

Figure 7 is a block schematic of components comprised in the Remote Service Device Sa-5d according to an embodiment of the invention of Figure 1. The Remote Service Device may be a gateway or bridge of some sort.

The schematic shows a processor 75 or processor core, a memory device 77 which may be in the form of memory registers, a memory storage device 78 for permanent or non-transitory storage of data, and a transmitter/receiver 79 for communication via private and or public wireless networks including the internet 10. An input/output (I/O) interface 73 is connected to the memory registers 77 (or temporary memory) and by a data bus to the other components 78, 75x, 79. The I/O interface may be a serial interface compatible with an industrial standard or defacto standard. The I/O interface 73 may be connected to a databus D1/D2 for bi- directional communication with a local field device such as 9a-9d connected to at least one industrial control system 20, 40. Optionally a wireless communication may be used between the Remote Service Device and a field device, for example via the wireless transmitter/receiver 79 and control system gateway WN 27. The components 73, 77, 78, 75, and 79 may be arranged in many different 10 15 20 25 30 21 ways. More than one of the functions or functionality of the Remote Server Device may be incorporated fewer components or even one single component, chip or Circuit.

For example in a wireless version of a Remote Service Device, a processor which is part of the wireless transceiver/receiver 79 may handle one or more functions of the Remote Service Device other than controlling wireless reception/transmission.

In some installations there may be several Remote Service Devices connected to the same network. For example there are a plurality of Remote Service Devices 5b-d shown at location B, Fig. 1. In such cases when there is a plurality of Remote Service Devices in the same network, the remote server 1 may keep a constant connection to one of the Remote Service Devices, which in turn may support forwarding commands to other Remote Service Devices in the same network but not currently connected to the remote server 1. This may be configured to be done when the remote server 1 detects a value for server resources that has exceeded a threshold value or the second threshold value.

Remote server 1 may optimise its use of resources by directing one presently-connected RSD to transmit commands, or information directed to RSDs and/or field devices, onward to a number of RSDs that are currently not-connected to the remote server 1. Using one RSD in a network to communicate to currently non-connected RSDs in the same network is an advantageous way to balance server resources according to a current server load, and according to a predicted server load. Thus the number of sudden disconnections and of interruptions of service by the remote server may be reduced, and response times may 10 15 20 25 22 also be reduced. Figure 8 is a flowchart of a related method to the method of Figure 1 showing in particular a method or process for one selected connected Remote Service Device to forward commands or other information from the remote server 1 to other, currently not connected Remote Service Devices in the same network or location such as location B. Fig. 8 comprises at least one of the steps of: 80 Remote server 1 detects an existing connection with a first RSD 5b in a network at a time when other RSDs 5b-5d are not currently connected, 82 Are the resources of remote server 1 below a second threshold? If No 83 no action but re-check at a later time; If Yes 84 then: 86 The remote server 1 sends selected commands for other, not currently connected, RSDs 5c-d to currently connected RSD 5b for onward transmission to the one or more of RSDs 5c-d.

In another embodiment the remote server may adapt the default value for a back-off time for a Remote Service device 5a-d based on a number of and duration of connection sessions with one or more of the currently connected Remote Service Devices during a predetermined time period. In this case the remote server 1 sends or broadcasts the update of the default back-off value to he RSDs or to a network manager function of the wired or wireless network used by the RSDs. 10 15 20 25 30 23 Local field device 9a in process 32 at location A is connected to the industrial control system 20 as well as a Remote Service Device 5a which connects the field device to the remote server 1. Local field devices 9b-d at location B are connected to the industrial control system 40 as well as to Remote Service Devices 5b-d which connect the respective field device 9b-d to the remote server. The two locations A, B may be separate and independent or may be two parts of one single industrial installation. The two industrial control systems 30, 40 may be completely separate control systems, or two parts of a single control system.

The methods of the invention may, as previously described, be carried out by means of one or more computer programs comprising computer program instructions or computer program code or software portions running on a computer or a processor. For example a microprocessor (or processors) in the remote server 1 which comprises a central processing unit CPU will carry out the steps of the method according to one or more functions of the invention for example as discussed in reference to Figures 4,5, 8.

The processor or processors may be in a Remote Service Device comprised as a network node or access point or bridge; the functionality may also be arranged in another device such as a gateway Qr a wireless gateway arranged with a network manager NM arrangement. In an embodiment the Remote Service Device may be arranged as a wireless device as indicated in Fig 7 with a wireless transmitter/receiver 79. The Remote Service Device is also arranged with computer program code or computer program instructions to establish communication and carry 10 15 20 25 30 24 out communication functions compatibly with the remote server l as well as with one or more industrial devices such as local field devices.

The computer programs discussed here comprise computer program code elements, instructions or software code portions that make the computer perform the method using equations, algorithms, data, stored values and calculations previously described. 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 processor may be a single processor or one core of a multi-core processor. The program in part or in whole may also be stored on, or in, 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, stored on a data server or on one or more arrays of data servers.

Other known and suitable media, including a data carrier or a removable memory media such as a USB memory stick and other removable flash memories, flash drives, hard drives etc. may also be used. One such data carrier 60 with computer program code 61, in the form of a CD ROM disc, is schematically shown in Figure 6. Such computer program may as an alternative be provided on another server and downloaded therefrom into the computer.

The inventive concept has mainly been described above with reference to a few examples. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the inventive concept, as defined by the appended claims.

Claims (25)

10 15 20 25 30 25 CLAIMS

1. A remote server (1) configured for receiving data communication from a local field device (9a-d) in a local installation (A, B) or process (32, 42), where the local field device is connected to a Remote Service Device (5a- d) configured for connecting the local field device to the remote server, characterised in that the remote server (1) comprises a computer or processor and computer program instructions for: balancing a data communication load on the remote server to optimise use of server resources by a plurality of Remote Service Devices (5a-n) and computer program instructions for sending commands to (5a-d) the Remote Service Device for collection of data from the local field device.

2. The remote server according to claim 1, wherein the remote server is arranged with computer instructions for sending a command to a RSD for at least one of: updating a software or firmware, updating a data collection parameter; communicating a back-off time; the RSD turning itself off; carrying out a maintenance function for the RSD.

3. The remote server according to claim 1 or 2, wherein the remote server is arranged to provide data collected from the local field device (9a-d) to a remote computer (3) for collection and analysis of the data of the local field device.

4. The remote server according to claim 1, wherein the remote server is arranged with computer instructions for- detecting a connection or reconnection attempt by a first Remote Service Device (5a), determining a number of currently connected Remote Service Devices (5b-d), - 10 15 20 25 30 26 calculating a value of resources of said remote server based in part on the number of currently connected Remote Service Devices, -comparing the resources value to a first threshold value and if the first value is not exceeded then establishing (45) the connection or re- connection.

5. The remote server according to claim 3, wherein if the first value is found to be exceeded, then retrieving connection statistics for other, connected Remote Service Devices (5b-d) (46), calculating how many of the other connected Remote Service Devices may need to be disconnected (48), calculating a time after which one additional Remote Service Device (5a) can be connected or re-connected (49) and sending the calculated back-off time (50) to the first Remote Service Device (5a).

6. The remote server according to claim 3 or 4, wherein a number is determined for how many of the currently connected Remote Service Devices which may need to be disconnected, and by calculating a length of time, a for which one of them should wait back-off time (52), before attempting re-connection.

7. The remote server according to claim 1 or 3, wherein the value of resources of said remote server is further predicted for a currently connected Remote Service Device based on number of and duration of connection sessions with the currently connected Remote Service Device during a time period.

8. The remote server according to claim 6, wherein the value of resources of said remote server is further predicted based on number of and duration of connection sessions with each of the currently connected one or more 10 15 20 25 30 27 Remote Service Devices during a predetermined time period.

9. The remote server according to any one of claims 3-7 wherein at least one Remote Service Device is disconnected without (54) a back-off message and the Remote Service Device attempts re-connection after a default back-off time or a predetermined time.

10. The remote server according to any one of claims 3, 4 or 7, wherein the remote server communicates the calculated (52) back-off time to the at least one Remote Service Device (5b-d) to be dis-connected and disconnects (56) it or them.

11. The remote server according to claim 8, wherein the default value for a back-off time is modified based on a number of and/or duration of connection sessions with one or more of the currently connected Remote Service Devices during a time period.

12. The remote server according to any one of claims 3-7 or 10 wherein the remote server (1) compares (82) the value of server resources to a second threshold value and if the resources value is below (84) the second threshold then the remote server sends a command (86) to a first, connected Remote Service Device (5c) containing an instruction to communicate the command to one or more other indicated Remote Service Devices (5b, 5-d).

13. The remote server according to claim 11, wherein the remote server (1) maintains, in an at least temporary record of one or more Remote Service Devices (5c) with a higher priority before disconnection than one or more (Sb, 5d) other Remote Service Devices in the same network 10 15 20 25 30 28 which is available for sending (86) commands or other information to other, (5b, not presently connected Remote Service Devices 5d) in the same network.

14. The remote server according to any previous claim, wherein a number of Remote Service Devices which are concurrently connected is part of a measurement and/or calculation determining the value of the server JfeSOurCeS .

15. A Remote Service Device (Sa-d) for communication with a remote server (1) and connected to a local field device (9a-d) in a local installation (A, B) or process (32, 42), which Remote Service Device is configured for connecting the local field device to the remote server, characterised in that the remote server (1) comprises a computer or processor and computer program instructions for: balancing a data communication load on the remote server to optimise use of server resources and receiving commands from the remote server for collection of data from the local field device by the Remote Service Device.

16. A Remote Service Device according to claim 15, wherein it comprises a processor or computer and computer program instructions for: attempting a connection or re- (1), instructions for receiving commands from the remote connection to the remote server and computer program server for collection of data from the local field device.

17. A Remote Service Device according to claim 15 or 16, wherein it is configured for receiving a command from the remote server (1) for at least one of: updating a software or firmware, updating a data collection parameter; communicating a back-off time; to the RSD for 10 15 20 25 30 29 turning itself off; carrying out a maintenance function for the RSD.

18. A Remote Service Device according to claim 16 or 17, wherein it is configured on being connected to the remote server for: either continuing and establishing the connection (45) or receiving a back-off signal (50) comprising a length of time before re-connection; if the latter then making a re-connection signal after the length of time has elapsed and re-connecting the local (l); former then connecting the local field device to the (1). field device (9a-d) to the remote server or if the remote server

19. A Remote Service Device according to any of claims 16-18, wherein the Remote Service Device is configured, on receiving a back-off signal from the remote server not comprising (54) an instruction for a length of time to wait before making a re-connection, to wait for a default back-off time or a predetermined time before making a re- connection attempt.

20. A Remote Service Device according to any of claims 15 to 19, wherein the Remote Service Device (5b) is configured, on receiving a signal (86) from the remote server (1) comprising an instruction for a command to be communicated to one or more other Remote Service Devices (5c-d), to communicate the command to the other Remote Service Devices (5c-d) indicated in the instruction.

21. A method for configuring a remote server (1) for receiving data communication from a local field device (9a-d) 42), in a local installation (A, B) or process (32, where the local field device is connected to a Remote Service Device (5a-d) configured for connecting 10 15 20 25 30 30 the local field device to the remote server, characterised in that the remote server (1) comprises a computer or processor and computer program instructions for: balancing a data communication load on the remote server to optimise use of server resources by a plurality of Remote Service Devices (5a-n) and computer program instructions for sending commands to the Remote Service Device (5a-d) for collection of data from the local field device.

22. A method for optimising a response time of a remote server (1) configured for receiving data communication from a local field device (9a-d) in a local installation (A, B) or process (32, 42), where the local field device is connected to a Remote Service Device (5a-d) configured for connecting the local field device to the remote server, characterised in that the remote server (1) comprises a computer or processor and computer program instructions for: balancing a data communication load on the remote server to optimise use of server resources by a plurality of Remote Service Devices (5a-n) and computer program instructions for sending commands to the Remote Service Device (5a-d) for collection of data from the local field device.

23. A method according to claim 20, wherein use of server resources by a plurality of Remote Service Devices (Sa-n) is optimised at least in part by: determining a number of currently connected Remote Service Devices (5a-d), calculating a value of resources of said remote server based in part on the number of currently connected Remote service Devices, comparing the resources value to a first threshold value and if the first value is not exceeded then establishing (45) the connection or re-connection. 10 31

24. A computer program product for carrying out one or more functions of a remote server (1) comprising computer-executable components for causing a device to perform the steps recited in any one of claims 1-14 when the computer-executable components are run on a computer OI' PIOCSSSOI' .

25. A computer program product for carrying out one or (5a-d) comprising computer-executable components for causing a more functions of a Remote Service Device device to perform the steps recited in any one of claims 15-19 when the computer-executable components are run on a COmputer OI' pIOCeSSOr.