Industrial control systems with multi-layer control logic execution

Abstract

The present invention relates to a process control system (200), the process control system comprising a process controller level (240) and an input / output (I / O) module level (230), the process controller level comprising at least one process controller (121, 122), the input / output (I / O) module level comprising at least one I / O module (231, 232, 233). The process controller level and the I / O module level are communicatively coupled and each comprises control logic, the control logic comprising control hardware or algorithm blocks (120a, 120b and 235a, 235b, 235c). The control logic in the process controller level and the I / O module level is configured to execute and exchange data to execute process control for a process run by the process control system in a distributed manner across the process controller level and the I / O module level.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims the benefit of provisional application serial number 63 / 047,049, filed on July 1, 2020, entitled "INDUSTRIAL CONTROL SYSTEM HAVING MULTI-LAYERED CONTROL LOGIC EXECUTION," which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates to a process controller arrangement for an industrial control system. Background Art

[0004] Industrial control systems typically include a hierarchical structure of control system hardware components, including process controllers, such as programmable logic controllers. The process controllers are coupled to input / output (I / O) modules that are used to interact with field devices coupled to processing equipment, wherein the field devices include sensors for sensing physical parameters and actuators for acting in accordance with control signals received from the controller to change settings on the processing equipment. In some known process controller applications, the process controller requires high-speed operation, such as having a maximum delay (latency) of a few thousandths of a second (milliseconds) measured from the time sensor data is received to the time control signals are generated in response to the sensor information. Although delays can be reduced by moving process control from the process controller to the I / O modules, this arrangement is generally not used because the resulting I / O connectivity and the resulting process control range are small. Summary of the invention

[0005] This Summary is provided to introduce a brief selection of disclosed concepts in a simplified form, which are further described below in the Detailed Description including the provided figures. This Summary is not intended to limit the scope of the claimed subject matter.

[0006] The disclosed aspects of the present invention recognize the delay problem of conventional process controllers of process control systems (PCS) including industrial control systems, which can cause these process controllers to have a slow response in response to changes in input values ​​sensed by sensors. Examples of applications requiring short delays can come from discrete control applications, which include factory automation, conveyors, fast machine control, and turbine control. In a specific exemplary application, a proximity switch (as a position sensor) input on a conveyor senses when a bottle is in a position to be filled with a liquid, and the process controller commands the opening of a valve, filling of the bottle, stopping of filling, and moving the bottle to the next position to cap the bottle in response to the input provided by the switch.

[0007] As another example, a position sensor is used to cut a material into strips, and the process controller commands an output to engage a cutting element in response to a sensed parameter received from the position sensor. The position sensor generally includes a proximity sensor configured to ensure that a worker's hand does not attempt to position the material (safety interlock) while the cutter is operating, which requires a short delay to meet its intended safety function.

[0008] One known PCS utilizes relatively high-speed logic implemented only in the process controller to achieve the latency levels required for certain applications. However, as the number of I / O points and the size of the logic increases, the architecture of conventional centralized process controllers that execute the logic can degrade latency performance. In such architectures, all control strategies tend to utilize computing (processing) resources and communication resources equally, even though typically only a subset of these strategies require short latency.

[0009] The disclosed control arrangement for a PCS places the control logic for controlling a process at two or more different levels, which results in the disclosed control system configuration supporting a moderate number of I / O points (such as up to 10,000 I / O points) while still having a short latency of typically 1 ms to 5 ms. The disclosed control arrangement achieves a trade-off between 1) the control range, meaning how many I / O points need to be connected for a single integrated control strategy, and 2) the latency that can be achieved between the process controller and the IO modules. Optionally, the I / O modules may include so-called universal I / O modules that support four different output types, including analog input (AI), analog output (AO), digital input (DI), and digital output (DO).

[0010] Aspects disclosed herein include a PCS including a process controller level and an I / O module level, the process controller level including a process controller, the I / O module level including at least one I / O module communicatively coupled to the process controller. Both the process controller level and the I / O module level include their own control logic, which includes control hardware and / or algorithm (software) blocks. There may also be a mix of hardware and algorithm blocks. The control logic in the process controller level and the I / O module level are each configured to execute and exchange data to perform process control for a process run by the PCS in a distributed manner distributed between the process controller level and the I / O module level. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 A portion of a conventional PCS including a pair of redundant process controllers shown in an exemplary controller configuration is shown in accordance with aspects of the present disclosure.

[0012] Figure 2 FIG. 1 shows a portion of a PCS disclosed in the present invention including control logic operating at multiple different levels. The PCS can be used with Figure 1 A conventional process control system is shown for comparison that executes its control logic only at the controller level. DETAILED DESCRIPTION

[0013] The disclosed aspects of the present invention are described with reference to the accompanying drawings, wherein similar reference numerals are used to refer to similar or equivalent elements in all drawings. The accompanying drawings are not drawn to scale, and they are provided only to illustrate the aspects disclosed herein. Several disclosed aspects are described below with reference to exemplary applications for illustration. It should be understood that many specific details, relationships, and methods are set forth to provide a complete understanding of the aspects disclosed herein.

[0014] Additionally, the terms "coupled to" or "coupled with..." (etc.) as used herein without further qualification are intended to describe either an indirect or direct electrical connection. Thus, if a first device is "coupled" to a second device, the connection may be through a direct electrical connection, where only parasitics exist in the path, or through an indirect electrical connection via intermediary items including other devices and connections. For indirect coupling, the intermediary items generally do not modify the information of the signal, but may adjust its current level, voltage level, and / or power level.

[0015] Figure 1 A portion of a conventional PCS 100 is shown including a redundant controller pair 120, including a primary controller 121 and a secondary controller 122, wherein the redundant controller pair 120 is shown connected to a plurality of I / O modules (shown as I / O modules 131, 132, and 133), wherein each I / O module generally supports a plurality of communication channels (also referred to as I / O points) respectively. The redundant controller pair 120 may be interfaced to the I / O modules 131, 132, and 133 via an I / O scanner.

[0016] The redundant controller pair 120 is also shown coupled to supervisory computers (shown as supervisory computers 141 and 142). In a conventional control system, the controller performs all algorithmic processing required to run the control loop, and the I / O modules perform receiving sensed information from sensors and driving actuators. The I / O hierarchy is shown to include I / O modules 131, 132, 133.

[0017] The control logic scheme disclosed in the present invention makes the control functions available at multiple PCS levels in addition to the conventional controller level, which is a level for conventional control systems such as Figure 1The control logic scheme disclosed in the present invention also includes control logic located in the I / O module, and if an I / O scanner is also provided in the PCS, the control logic may also be located in the I / O scanner. As described above, the I / O module may include so-called universal I / O modules that support AI, AO, DI, and DO shown on the same I / O module. The control logic disclosed in the present invention may be implemented in software (such as firmware) or hardware (for example, using a programmable gate array (PGA)).

[0018] The disclosed scheme of running control logic at multiple levels achieves low screw-to-screw delay for fast control loops by bringing the control logic closer to the I / O screws. As used herein, the term "screw" is an abbreviated term for an I / O cable, and the screw refers to a connection to a grayscale analog signal (such as a highway addressable remote transducer (HART) protocol signal or a single-bit discrete signal) that provides a connection from an I / O module to a field device (sensor or actuator) on a terminal block. Running control logic on the I / O module also prevents delays in data flow to the controller and when the controller sends control signals back to the I / O module.

[0019] Figure 2 FIG. 2 shows a portion of a PCS 200 including control logic operating at a plurality of different levels. The PCS 200 may be used with Figure 1 PCS 100 is shown for comparison, with control logic running only at the controller level. Although the control logic in PCS 200 is shown as being implemented in software by including algorithm blocks, as described above, the control logic may also be implemented using hardware or a mix of hardware and software.

[0020] Figure 2 Each algorithm block shown on the right can be implemented as a function block, ladder logic, text program block, or can be implemented using a language specified in a standard such as IEC61131-3 or any suitable programming language that can be implemented in hardware or software. IEC 61131-3 is known to be the third part (of 10 parts) of the open international standard IEC 61131 for programmable logic controllers, which was first published in December 1993. Figure 2The illustrated PCS 200 includes an I / O module level 230 including I / O modules optionally shown as common I / O modules 231, 232, and 233, an optional scanner level 250 having an I / O scanner 215, and a process controller level 240 including process controllers optionally shown as redundant process controllers 120 including a primary controller 121 and a backup controller 122. As with the PCS 100, the redundant controller pair 120 is shown coupled to supervisory computers (shown as supervisory computers 141 and supervisory computers 142).

[0021] The algorithm blocks are shown at multiple levels in the PCS 200, shown at 120a, 120b at the controller level 240, shown at 215a and 215b at the I / O scanner level 250, and shown at 235a, 235b, and 235c at the I / O module level 230. These algorithm blocks are shown as being communicatively coupled together (such as by an Ethernet connection) and are configured to all be executed simultaneously at the three different levels 230, 240, and 250 shown, and also to exchange data in a distributed manner across each of these levels to perform process control of the process. In one aspect, the simultaneous control processing occurring at the process controller level 240, the I / O scanner level 250, and the I / O module level 230 can be synchronized. On the other hand, the process control occurring at these respective levels can be asynchronous.

[0022] In addition to at least one other input type, the universal I / O modules 231, 232 and 233 may also support pulse input and frequency input. Although not shown, the I / O scanner 215 may also be redundantly arranged, and each of the universal IO modules 231, 232 and 233 may also be redundantly arranged. On the contrary, although the controller module is shown as a redundant controller arrangement (which is shown as a control pair 120 including controller 121 and controller 122). However, the controller module can be implemented using one or more non-redundant controllers. In addition, the algorithm blocks disclosed in the present invention can run on any of the three levels 230, 250 and 240, regardless of whether they are redundant. The term layer is sometimes replaced by the term layer of the reference PCS.

[0023] Configuration of PCS 200 can be achieved by creating different types of containers for different levels. The term "container" as used herein allows each level in PCS 200 to support a different set of algorithm blocks. Containers may also be referred to as program organization units (POUs). A container or control program can run a variety of different algorithm block types as needed. Depending on the level at which control is executed, the set of potential algorithm blocks can be broad and inclusive, or can be more specialized.

[0024] However, generally speaking, any algorithm block may be run at any level of the process control system. Each of the containers may be converted into a loadable module that is configured to be downloaded to a corresponding level of the control system implementing the control logic. With respect to the control logic, the control logic is executed independently at each level (synchronously or asynchronously as described above), and data is exchanged between the levels connecting the data.

[0025] The control logic at the lowest level of the PCS 200 is shown to include common I / O modules 231, 232, 233, which can be implemented by executing downloaded modules. The use of compiled algorithm blocks enables the download of updated algorithm block types without modifying the software or firmware at the level 230 with the I / O modules, nor the software or firmware at the level 230. With respect to firmware, the nature of the configuration or program loaded into the various levels of the control processing host can be any of a number of possibilities. The algorithm block program code can be in a read-only memory (ROM) or other memory of the device, where the data configuration is loaded, the algorithm block code can be loaded directly as executable code, or the control algorithm running in the control process can be implemented as a combination of loaded code and loaded data.

[0026] Although various inventions disclosed herein have been described above, it should be understood that they are presented by way of example only and not as limitations. Many changes may be made to the disclosed aspects according to the disclosure herein without departing from the spirit or scope of the disclosure. Therefore, the breadth and scope of the disclosure should not be limited by any of the above-mentioned implementation aspects. On the contrary, the scope of the disclosure should be limited according to the following claims and their equivalents.

Claims

1. A process control system (200), comprising: a process controller hierarchy (240), the process controller hierarchy comprising at least one process controller (121, 122), a scanner level (250) located between the process controller level and the input / output I / O module level, comprising at least one I / O scanner (215), wherein the I / O scanner comprises control logic, the control logic comprising control hardware or algorithm blocks, wherein the I / O scanner is configured to interface the at least one process controller of the process controller level with at least one I / O module of the I / O module level; and an I / O module hierarchy (230) comprising at least one I / O module (231, 232, 233) coupled to the process controller; wherein the process controller level and the I / O module level are communicatively coupled and both include control logic including control hardware or algorithm blocks implemented as at least one of function modules, ladder logic modules, or text program modules; and wherein the control logic is placed in two or more different levels of the process control system including the process controller level, the scanner level and the I / O module level, and is configured to execute and exchange data to perform process control of the process run by the process control system in a distributed manner across the process controller level and the I / O module level.

2. The process control system of claim 1, wherein the at least one I / O module comprises a plurality of I / O modules, each of the I / O modules comprising a general purpose I / O module supporting analog input, analog output, digital input, and digital output. 3 . The process control system of claim 1 , wherein the control logic in both the process controller level and the I / O module level includes only the control hardware.

4. The process control system of claim 1, wherein the at least one process controller comprises a redundant controller arrangement including an independent first process controller (121) and a second process controller (122).

5. A method of operating a process control system comprising a process controller level, an I / O module level, and a scanner level, the process controller level comprising at least one process controller, the I / O module level comprising at least one I / O module coupled to the process controller, and the scanner level comprising at least one I / O scanner (215) located between the process controller level and the input / output I / O module level, the method comprising: providing the process controller level and the I / O module level, the process controller level and the I / O module level being communicatively connected and both including control logic including control hardware or algorithm blocks implemented as at least one of function modules, ladder logic modules, or text program modules, wherein the I / O scanner includes control logic including control hardware or algorithm blocks, wherein the I / O scanner is configured to interface the at least one process controller of the process controller level with at least one I / O module of the I / O module level; as well as Using control logic placed in two or more different levels of a process control system, including the process controller level, the scanner level, and the I / O module level, to execute and exchange data, and to perform process control of a process run by the process control system in a distributed manner across the process controller level and the I / O module level.

6. The method of claim 5, wherein the at least one I / O module comprises a plurality of the I / O modules, the plurality of I / O modules comprising at least one general purpose discrete I / O module that supports digital input and digital output but does not support analog input or analog output. 7 . The method of claim 5 , wherein the control logic at the process controller level and in the I / O module level includes only the algorithm block.

8. The method of claim 5, wherein the at least one process controller comprises a redundant controller arrangement including independent first and second process controllers.

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