ST-type sequential control programming template for DCS (Distributed Control System)

Abstract

The invention discloses an ST type sequence control programming template for a DCS (Distributed Control System), aiming at the problems of difficulty in starting and low efficiency of the existing sequence control programming, the ST type sequence control programming template is configured to have a frame structure, a state transition module and an instantiation module, the programming starting difficulty is reduced through a templated, normalized and logical program, and the programming efficiency is improved. According to the method, the working efficiency is improved, the method is easy to maintain, the lower limit of ST programming is raised, and high-quality sequential control is finally obtained due to the fact that the upper limit of ST programming is high.

Description

Technical Field

[0001] The invention belongs to the technical field of DCS sequential control, and in particular relates to an ST type sequential control programming template for a DCS system. Background Art

[0002] In terms of sequential control programming, programming can be achieved through ST, SFC, FBD, and LD. Among them, ST has a high degree of freedom and flexible programming, and has a high upper limit for sequential control programming. But at the same time, the lower limit is also low. There is no configuration at the beginning, and everything needs to be configured.

[0003] SFC sets a framework structure based on the state transition diagram, and sequential control programming must be based on the framework. The framework itself cannot be modified, which limits flexibility and locks the upper limit. However, the existence of the framework itself raises the lower limit. For now, different state transition diagrams are developed and different framework structures are set to meet different sequential control requirements, such as state transition diagrams designed according to ISA 88 and ISA 106 standards.

[0004] FBD can be viewed as a collection of various simple function blocks. It is adequate for handling simple sequential controls, but is clearly inadequate for handling complex and ever-changing sequential controls.

[0005] LD is often used to process Boolean data. For other types of data, such as analog quantity processing, it is necessary to use function blocks and other means, which is similar to FBD in processing sequence control.

[0006] In summary, FBD and LD are not suitable for sequential control, while SFC is generally used in specific scenarios, and it is not easy to modify the framework for special needs, so ST is generally used for sequential control programming. During the project implementation process, due to the lack of a unified general programming template, there are problems such as difficulty in programming, low efficiency, and difficulty in maintenance. Summary of the invention

[0007] The purpose of the present invention is to provide an ST type sequential control programming template for a DCS system, which reduces the difficulty of programming, improves work efficiency and makes it easy to maintain through templated, standardized and logical programs.

[0008] To solve the above problems, the technical solution of the present invention is: An ST type sequential control programming template for a DCS system, comprising: a framework structure, a state transition module and an instantiation module; The framework structure includes a data processing area and a programming area. The data processing area is configured to implement preprocessing, secondary processing, command control and synchronous processing of specified parameters of sequential control data. When command control is performed, the state transition module is called to perform state switching according to the current command and the judgment condition. The programming area is configured to implement the writing of the pre-program, main program and post-program of the sequential control to complete the sequential control function code. The state transition module is configured to implement a process including running, pausing, resuming, stopping, abandoning and skipping, wherein the skipping must be performed after pausing; The instantiation module is configured to instantiate the sequential control function codes by level to obtain multi-level function blocks to adapt to multi-scenario applications.

[0009] According to an embodiment of the present invention, the data processing area includes a pre-processing area, a command control area, and a secondary processing area; The pre-processing area is configured to implement data protection, data squaring, data high and low amplitude limiting, and small signal removal processing; The command control area is configured to implement state switching according to the current command and the determination condition; The secondary processing area is configured to implement state-changed data processing.

[0010] According to an embodiment of the present invention, the programming area includes a pre-global area, a first state recording area, a main program area, a post-processing area, a post-global area and a second state recording area; The pre-global area is configured to write a program that is executed before the main program in each cycle; The first state recording area is configured to achieve a synchronization of the specified parameters; The main program area is configured to implement main program writing; The post-processing area is configured to compare the parameters in the first state recording area with the parameters updated by the main program to adjust the parameters; The post global area is configured to write a program that is executed after the main program in each cycle; The second status recording area is configured to implement secondary synchronization of designated parameters.

[0011] According to an embodiment of the present invention, the state transition module is further configured to implement exception handling including failure, interlocking, queue loss, emergency stop, and emergency abandonment. When the exception handling occurs, the state transition module executes the suspension process.

[0012] According to an embodiment of the present invention, the instantiation module is further configured to implement a flow chart sequence control panel.

[0013] Due to the adoption of the above technical solution, the present invention has the following advantages and positive effects compared with the prior art: The ST type sequential control programming template for the DCS system in one embodiment of the present invention aims at the problems of difficulty in getting started and low efficiency of existing sequential control programming. By configuring the ST type sequential control programming template, it has a framework structure, a state transition module and an instantiation module; wherein the framework structure includes a data processing area and a programming area, and the data processing area is configured to realize the preprocessing, secondary processing, command control and synchronous processing of the specified parameters of the sequential control data; the programming area is configured to realize the writing of the pre-program, main program and post-program of the sequential control to complete the sequential control function code; the state transition module is configured to realize the process including running, pausing, resuming, stopping, abandoning and skipping; the instantiation module is configured to instantiate the sequential control function code by level, and obtain multi-level function blocks to adapt to multi-scenario applications. Through the templated, standardized and logicalized program, the difficulty of programming is reduced, the work efficiency is improved, and it is easy to maintain, thereby raising the lower limit of ST programming. Because the upper limit of ST programming itself is high, high-quality sequential control is finally obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of a ST type sequential control programming template for a DCS system in one embodiment of the present invention; Figure 2 It is a schematic diagram of a framework structure in one embodiment of the present invention; Figure 3 A schematic diagram of state transition in one embodiment of the present invention; Figure 4 is a schematic diagram of instructions in one embodiment of the present invention; Figure 5 is a schematic diagram of template functions in one embodiment of the present invention; Figure 6 A schematic diagram of the logic construction of functional blocks in one embodiment of the present invention; Figure 7 A schematic diagram of buttons on a sequential control panel in an embodiment of the present invention; Figure 8 Schematic diagram of a sequential control panel in an embodiment of the present invention. DETAILED DESCRIPTION

[0015] The ST type sequential control programming template for a DCS system proposed by the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description and claims.

[0016] Please see Figure 1This embodiment provides an ST type sequential control programming template for a DCS system, including: a framework structure 1, a state transition module 2 and an instantiation module 3; the framework structure 1 includes a data processing area and a programming area, wherein the data processing area is configured to implement preprocessing, secondary processing, command control and synchronous processing of specified parameters of sequential control data, and when performing command control, the state transition module is called to execute state switching according to the current command and judgment conditions; the programming area is configured to implement the writing of a pre-program, a main program and a post-program of the sequential control to complete the sequential control function code.

[0017] The state transition module 2 is configured to implement a process including running, pausing, resuming, stopping, abandoning and skipping, wherein the skipping must be performed after pausing.

[0018] The instantiation module 3 is configured to instantiate the sequential control function codes by level to obtain multi-level function blocks to adapt to multi-scenario applications.

[0019] The above-mentioned sequential control programming template is configured with a framework structure and a state transition diagram. Through templated, standardized and logical programs, it reduces the difficulty of programming, improves work efficiency and makes it easy to maintain, thereby raising the lower limit of ST programming. Because the upper limit of ST programming itself is high, high-quality sequential control is ultimately obtained.

[0020] For details, please see Figure 2 The framework structure 1 includes a pre-processing area, a command control area, a secondary processing area, a pre-global area, a first state recording area, a main program area, a post-processing area, a post-global area and a second state recording area. Since ST language programming is adopted, all parts can be edited. Based on better differentiation of functions and limitation of the programming area for engineers, this embodiment establishes the framework structure, which is mainly divided into 9 areas: Preprocessing area: preprocess the data, such as data protection, square root, high and low limit, small signal removal, etc.

[0021] Command control: switch the state to the specified state according to the current command and judgment conditions.

[0022] Secondary processing: Processing of situations such as faults that can change the status, during which the status record parameters of the previous cycle may be used.

[0023] Pre-global: used to write a program that is executed before the main program in each cycle.

[0024] First state record: synchronize the specified parameters once.

[0025] Main program: the main programming area.

[0026] Post-processing area: Compare the parameters recorded in the status with the parameters updated by the main program, process the internal parameters of the program, and the post-global parameters may be used, so they are placed before them.

[0027] Post global: used to write a program that will be executed after the main program in every cycle.

[0028] Second state record: perform secondary synchronization on the specified parameters.

[0029] In actual applications, after importing the program template, the framework structure and corresponding code will be automatically generated. Engineers only need to program the main program area according to different sequential control requirements.

[0030] The state transition module 2 in this embodiment refers to the ISA106 and ISA88 standards, and is designed based on the actual situation of common on-site sequential control. It covers the commonly used running, pausing, resuming, and stopping processes of sequential control, and has an abandonment process for situations where the stop cannot be ended normally. The pause and hold processes are integrated; the skip step process is added, and it is stipulated that the skip step process can only be skipped in the case of a pause; the exception handling in the case of faults, interlocking, queue loss, emergency stop, emergency abandonment, etc. is expanded; and functions such as automatic reset and forced reset are set. While expanding ISA106, it is not as bloated as ISA88, making it more suitable for the actual use of on-site sequential control.

[0031] For details, please see Figure 3 The state transition diagram includes multiple states such as Idle, Running, Paused, Resuming, Paused, Skipping, Stopping, Abandoned, Completed, Stopped, Abandoned, etc. Please refer to Figure 4 , the state transition module 2 uses the following instructions to implement state switching: When in any state, after receiving the absolute reset command, the switching state is idle; when the idle state receives the start command, the switching state is running; when the running state meets its preset conditions, the switching state is completed; when the running state receives any command of pause, fault, interlock, and queue loss, the switching state is paused; when the paused state receives a jump command, the switching state is jumping; when the paused state meets its preset conditions, the switching state is paused or stopped; when the paused state receives a resume command, the switching state is resuming; when the stopped state meets its preset conditions, the switching state is stopped.

[0032] When any of the states such as running, pausing, paused, skipping, resuming, and stopping receives a abandon or emergency abandon command, the switching state is abandoned; when the abandoning state meets its preset conditions, the switching state is abandoned.

[0033] When any state such as Completed, Stopped, or Abandoned receives a reset or auto-reset command, the state switches to Idle.

[0034] The state transition module in this embodiment performs the following configuration when processing the skip step: First, define that only in the jump step, the program is allowed to reset the current step. If you want to switch to the jump step, you must first ensure that the program is paused, that is, in a safe state. In other states, whether in the logic or on the panel, it will be protected to prevent the user from accidentally changing the current step. Here, the jump is the step of the running process. Other states are not applicable to jump steps. In other states, jumps will generally not be triggered, and generally they will not get stuck. In other states, they will take steps, give up, or absolutely reset, etc.

[0035] There are many reasons for resetting the current step, such as the current step switching condition cannot be met due to unexpected circumstances, or the previous step is not manually judged to be in place and needs to be executed again, etc. In the existing state transition, the jump step can be performed in any state, and the operation is not well protected.

[0036] The instantiation module 3 in this embodiment is used to instantiate the ST type sequential control programming template into a function block, which is divided into SKMB_1 (primary), SKMB_2 (intermediate), SKMB_3 (advanced), and G_ST_SKMB (global) according to the level. Different types of templates can be selected for construction according to the usage scenario. Among them, the functions of each level module can be seen in Figure 5 .

[0037] In practical applications, ST type sequential control programming templates need to be instantiated in the form of function blocks and spliced ​​with other function blocks in the FBD program page to interact with data, such as Figure 6 The following figure shows a sequential control function block edited based on the SKMB_3 template.

[0038] The instantiation module 3 is also configured to implement a flow chart sequential control panel. Figure 7 , the figure shows the button of the sequence control panel, which can be used to call up the sequence control panel. Figure 8 From top to bottom and from left to right, the sequence control panel includes the sequence control program description, control authority and manual and automatic switching area, program specific parameter setting area, status indication area, logic execution sequence selection area, command control area, step and jump area, time display area, LOGO display area, program step column area, program description area, control instructions and program status indication area. The program running status can be intuitively seen through the sequence control panel.

[0039] In summary, the sequential control programming template for the DCS system provided in this embodiment configures the ST type sequential control programming template to have a framework structure, a state transition module and an instantiation module. Through templated, standardized and logical programs, the difficulty of programming is reduced, work efficiency is improved, and maintenance is easy, thereby raising the lower limit of ST programming. Because the upper limit of ST programming itself is high, high-quality sequential control is ultimately obtained.

[0040] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalents, they still fall within the protection scope of the present invention.

Claims

1. A ST type sequential control programming template for a DCS system, characterized in that: include: Framework structure, state transition module and instantiation module; The framework structure includes a data processing area and a programming area. The data processing area is configured to implement preprocessing, secondary processing, command control and synchronous processing of specified parameters of sequential control data. When command control is performed, the state transition module is called to perform state switching according to the current command and the judgment condition. The programming area is configured to implement the writing of the pre-program, main program and post-program of the sequential control to complete the sequential control function code. The state transition module is configured to implement a process including running, pausing, resuming, stopping, abandoning and skipping, wherein the skipping must be performed after pausing; The instantiation module is configured to instantiate the sequential control function codes by level to obtain multi-level function blocks to adapt to multi-scenario applications.

2. The ST type sequential control programming template for a DCS system as claimed in claim 1, characterized in that: The data processing area includes a pre-processing area, a command control area, and a secondary processing area; The pre-processing area is configured to implement data protection, data squaring, data high and low amplitude limiting, and small signal removal processing; The command control area is configured to implement state switching according to the current command and the determination condition; The secondary processing area is configured to implement state-changed data processing.

3. The ST type sequential control programming template for a DCS system as claimed in claim 1, characterized in that: The programming area includes a pre-global area, a first state recording area, a main program area, a post-processing area, a post-global area and a second state recording area; The pre-global area is configured to write a program that is executed before the main program in each cycle; The first state recording area is configured to achieve a synchronization of the specified parameters; The main program area is configured to implement main program writing; The post-processing area is configured to compare the parameters in the first state recording area with the parameters updated by the main program to adjust the parameters; The post global area is configured to write a program that is executed after the main program in each cycle; The second status recording area is configured to implement secondary synchronization of designated parameters.

4. The ST type sequential control programming template for a DCS system as claimed in claim 1, characterized in that: The state transition module is also configured to implement exception processing including failure, interlocking, queue loss, emergency stop, and emergency abandonment. When the exception processing occurs, the state transition module executes the suspension process.

5. The ST type sequential control programming template for a DCS system as claimed in claim 1, characterized in that: The instantiation module is also configured to implement a flow chart sequence control panel.

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