Event-Oriented Transmission of Measured Process Values

Abstract

A method for event-oriented transmission of measured process values includes receiving the measured process values via an automation device of a control system of a process plant; automatically performing sensitization or desensitization of a measurement range of the measured process values on the automation device where, during sensitization or desensitization and depending on an undershoot of a minimal transmission rate of the measured process values from a measurement device to the automation device or an overshoot of a maximum transmission rate of the measured process values from the measurement device to the automation device, the measurement range is automatically decreased during sensitization and increased during desensitization by the automation device via a heuristic method, and transmitting the measured process values, on an event-oriented basis, to the operator station server of the control system of the process plant, where an event represents a predetermined change to the measured process values.

Claims

1.-3. (canceled)

4. A method for an event-oriented transmission of process measurement values from at least one measurement device of a control system of a process installation to an operator station server of the control system of the process installation, the method comprising: a) receiving the process measurement values via an automation device of the control system of the process installation; b) reducing a measurement range of the process measurement values automatically via the automation device of the control system of the process installation via a heuristic method as part of a sensitization of a change recognition of the process measurement values as a function of a drop below a minimum transmission rate of the process measurement values from the measurement device to the automation device, and increasing the measurement range of the process measurement values via the automation device of the control system of the process installation automatically as part of a desensitization of a change recognition of the process measurement values; and c) transmitting the process measurement values in an event-oriented manner to the operator station server of the control system of the process installation, wherein an event represents a predetermined change of the process measurement values.

5. An automation device, comprising: a processor; and memory; wherein the automation device is configured to: a) receive process measurement values within a control system of a process installation; b) reduce a measurement range of the process measurement values automatically within the control system of the process installation via a heuristic method as part of a sensitization of a change recognition of the process measurement values as a function of a drop below a minimum transmission rate of the process measurement values from a measurement device to the automation device, and increase the measurement range of the process measurement values within the control system of the process installation automatically as part of a desensitization of a change recognition of the process measurement values; and c) transmit the process measurement values in an event-oriented manner to an operator station server of the control system of the process installation, wherein an event represents a predetermined change of the process measurement values.

6. The automation device as claimed in claim 5, wherein the automation device comprises a programmable logic controller.

7. A control system of a process installation, the control system including the an automation device as claimed in claim 5.

8. The control system as claimed in claim 7, wherein the automation device comprises a programmable logic controller.

Description

[0027] The above-described properties, features and advantages of this invention and the manner in which these are achieved will now become clearer and more intelligible in conjunction with the following description of the exemplary embodiment, which will be explained in detail making reference to the drawings, in which:

[0028] FIG. 1 shows a course of a process measurement value processed in accordance with the prior art;

[0029] FIG. 2 shows a further course of a process measurement value processed in accordance with the prior art;

[0030] FIG. 3 shows a schematic diagram of a method according to the invention;

[0031] FIG. 4 shows a course of a process measurement value processed in accordance with a method according to the invention; and

[0032] FIG. 5 shows a schematic drawing of a part of a control system.

[0033] FIG. 1 shows an exemplary course of a process measurement value in an XY diagram with arbitrary units. The process measurement value is processed cyclically in an automation device. The quantity of process measurement values is to be thinned out before the transmission to an operator station server of a control system of a process installation, in order to avoid having to transmit each individual process measurement value.

[0034] A method for the event-oriented transmission in accordance with the prior art is used, which uses a measurement range configured in a fixed manner, a minimum and maximum transmission rate as well as a threshold value for the hysteresis. In the course in accordance with FIG. 1, the process measurement values that are marked with crosses have been selected by the known method for transmission from the automation device to the operator station server. It can be seen that a good reduction is achieved with the configured measurement range with strong thinning out. A reproduction of the process measurement value course is imprecise, however, as no process measurement values are transmitted during important events (jumps and “kinks”).

[0035] In contrast to FIG. 1, for the same course of process measurement values, a measurement range with a low thinning out is chosen in FIG. 2, so that reproduction is more accurate, as process measurement values are also transmitted during important events (jumps and “kinks”). Conversely, however, only a low reduction is achieved during the transmission of the process measurement values from the automation device to the operator station server—particularly in the regions with low change, considerably more process measurement values are transmitted than would be necessary.

[0036] What is essential is the measurement range during the accumulation of the process measurement value changes since the last transmission: [0037] if the measurement range is chosen to be too small, then accumulation takes place too quickly and accordingly too many process measurement values are also transmitted, which has negative effects on the achievable transmission rate; [0038] if the measurement range is chosen to be too large, then accumulation takes place too slowly and accordingly few process measurement values are transmitted, which has negative effects on a reproduction of the process measurement values.

[0039] For an optimum configuration (measurement range, minimum/maximum transmission rate, threshold value), a project engineer of the process installation has to set the suitable parameters measurement point by measurement point or measurement device by measurement device. The process installation also has to move within the parameters configured for this. Exceptional situations, such as the commissioning of sensors, failures of sensors or other interruptions, for example, therefore cannot be optimally transmitted and processed by operators of the process installation.

[0040] In FIG. 3, the principle of the self-sensitizing and desensitizing measurement range is illustrated. This is based on the same process measurement value course as FIG. 1 and FIG. 2. The process measurement values selected for the transmission are marked with a cross. The measurement range is the respective distance between the first curve 1 (at the top in the figure) and the second curve 2 (at the bottom in the figure).

[0041] It can be seen that the measurement range changes over the course of the process measurement values:

[0042] Section I: the measurement range changes dynamically with the minimum and maximum process measurement values in the range—this leads to a desensitization of the change recognition and thus to a reduction of the process data transmission.

[0043] Section II: the process measurement value course has reached a stable level—the measurement range is constant. Considerably fewer process measurement values are transmitted.

[0044] Section III: there has been a drop below the minimum transmission rate due to the strong desensitization due to the large measurement range—the measurement range is dynamically reduced. In this context, a heuristic method is used, in which the distance between the current process measurement value and the upper and lower limits of the measurement range is halved. This is referred to in the present case as sensitization. The process measurement values are now sent again, more quickly, and the change recognition is more sensitive again.

[0045] Section IV: due to the previous sensitization, a change in the process measurement values is immediately recognized and transmitted. Due to the change of the process measurement values, the measurement range is adjusted again.

[0046] Section V: due to the strong change of the process measurement value, the measurement range is increased again (desensitized), until there is a drop below the minimum transmission rate again due to the process value settling at a level.

[0047] Section VI: the measurement range is optimally set to the level of the process measurement value and is no longer modified—a constant transmission takes place.

[0048] FIG. 4 shows the course of the process measurement values shown in FIG. 1 and FIG. 2 as a continuous line. The process measurement values selected on the basis of the method explained on the basis of FIG. 3 for transmission from the automation device to the operator station server are marked by crosses. It can be seen that a very good reduction during the transmission can be achieved, particularly at the settled level of the process measurement value. Nevertheless, it is possible to be able to respond to events in an ad hoc manner during the transmission. Thus, kinks, jumps and gradients for example are captured in an exact manner by the transmission, so that reproduction is very possible after transmission from the automation device to the operator station server. Moreover, it is possible to see how the transmission rate is adjusted dynamically within the stipulated limits.

[0049] FIG. 5 shows a part of a control system 3 according to the invention of a process installation. The control system 3 comprises a server of an operator control system or an operator station server 4 and an operator station client 5 associated therewith. The operator station server 4 and the operator system client 5 are interconnected via a terminal bus 6 and are connected to further components (not shown) of the control system 3, such as an engineering system server or a process data archive.

[0050] A user or operator has access to the operator station server 4 by means of the operator station client 5 by means of the terminal bus 6, in the context of operator control and monitoring. The terminal bus 6 can be embodied as an industrial Ethernet for example, without being restricted to this.

[0051] The operator station server 4 has a device interface 7 which is connected to an installation bus 8. This can be used by the operator system server 2 to communicate with an automation device 9 of the control system 3. The installation bus 8 can be embodied, without being limited thereto, as an industrial Ethernet, for instance. In turn, the automation device 9 may be connected to any number of subsystems (not shown).

[0052] Integrated in the operator station server 4 is a visualization service 10, via which a transmission of (visualization) data to the operator station client 5 can take place. Additionally, the operator station server 4 has a process image 11 of the process installation.

[0053] Implemented in the automation device 9 is what is known as an EDC framework 12 (Event Driven Communication), which enables an event-based transmission of process measurement values from measurement devices (not shown) connected to the automation device 9 to the operation station server 4. As part of the EDC framework 12, a sensitization and/or desensitization according to the invention of a measurement range of the process measurement values takes place before the process measurement values are transmitted to the operator station server 4. In this context, the current process measurement values are analyzed by the EDC framework 12 in each cycle of the automation of the process installation. Although the “thinning out” of the process measurement values causes a somewhat higher computational effort for the automation device 9, this is advantageously overcompensated by the saving of computational effort during the transmission of the process measurement values to the operator station server 4.

[0054] Although the invention has been illustrated and described in greater detail with the preferred exemplary embodiment and the figures, the invention is not restricted by the examples disclosed and other variations can be derived therefrom by the person skilled in the art without departing from the protective scope of the invention.