A hierarchical pump group start-stop control system and method based on atmosphere mode switching and token interlocking

Abstract

The application provides a hierarchical pump group start-stop control system and method based on atmosphere mode switching and token interlocking, and belongs to the field of intelligent control of vacuum thermal equipment multi-stage pump groups; solves the problems of load start, vacuum fluctuation, frequent misoperation and rigid control caused by single parameter determination, no working condition distinction, no permission interlocking and no dynamic intervention in the existing vacuum thermal equipment multi-stage pump group control; the technical scheme is as follows: the system comprises a man-machine interactive configuration module and a PLC controller in communication connection with the man-machine interactive configuration module, and the output end of the PLC controller is connected with multiple pump groups; the man-machine interactive configuration module is used for setting a process atmosphere mode and completing pump group pre-selection configuration; a pump group state acquisition module of the PLC controller is used for collecting the running state information of each pump group to be measured in real time; and the application is applied to vacuum thermal equipment.

Description

Technical Field

[0001] This invention relates to the field of intelligent control technology for multi-stage pump sets in vacuum thermal equipment, specifically to a staged pump set start-stop control system and method based on atmosphere mode switching and token interlocking. Background Technology

[0002] Vacuum thermal equipment (such as high-temperature graphitization furnaces and carbon / ceramic deposition furnaces) is a key process equipment in new materials, aerospace, and high-end manufacturing fields. The achievement and maintenance of the vacuum environment in these systems directly determines product quality and production safety. The vacuum systems of such equipment typically consist of multiple multi-stage pump units, including mechanical pumps (rotary vane pumps), Roots pumps (booster pumps), and diffusion pumps or molecular pumps. Different low-vacuum, medium-vacuum, and high-vacuum pumps are selected according to process requirements. Taking a Roots pump unit as an example, its startup must strictly follow the sequence requirement of "starting the forestage mechanical pump first, and only starting the Roots pump after the forestage pump has pumped the system pressure to the allowable startup pressure of the Roots pump." If the forestage pump has not reached steady-state operation before the subsequent Roots pump is forcibly started, it will cause the subsequent pump to start under load, leading to motor overload, pump unit impact damage, or even equipment failure.

[0003] In the actual production of vacuum thermal equipment, the process operation requires alternating between two atmosphere modes: low-vacuum replacement and high-vacuum precision control. The low-vacuum stage (1200 Pa - atmosphere) is usually completed by a mechanical pump, while the high-vacuum stage (below 1200 Pa) requires the activation of a Roots pump, diffusion pump, or molecular pump. Different operating conditions have significantly different requirements for pumping speed, ultimate vacuum, and start-up / shutdown sequence. The pump control system must have the ability to adapt to different operating conditions; otherwise, it will lead to vacuum fluctuations, uncontrolled process environment, and ultimately product quality defects.

[0004] In response to the aforementioned need for automated control of vacuum pump units, those skilled in the art have conducted relevant research, but the following systemic technical deficiencies still exist: First, the judgment relies on a single criterion and fails to detect the pump unit's own operating status. Current technology only detects external media parameters such as vacuum level and valve status, without collecting internal parameters such as pump unit operating current, contactor status, and fault signals. This makes it impossible to determine whether a single pump has truly entered steady-state operation. Relying solely on media parameters can easily lead to "false steady-state" conditions—that is, the vacuum level meets the standard, but the upstream pump has not actually reached a reliable operating state. Triggering the downstream pump in this situation will result in load-bearing start-up, impact overload, and in severe cases, equipment damage.

[0005] Secondly, the lack of condition-specific logic results in poor process adaptability. Traditional fixed-sequence control and vacuum-triggered pump start-up logic fail to differentiate between the two distinct process requirements of low-vacuum replacement and high-vacuum precision control, employing a uniform start-up and shutdown strategy throughout. This often leads to: redundant startup of the high-vacuum pump unit during the low-vacuum phase, resulting in energy waste and unnecessary equipment wear; and insufficient power in the foreboard pump during the high-vacuum phase, causing the vacuum level to fail to meet process requirements. This "one-size-fits-all" control mode directly causes fluctuations in the furnace vacuum environment, leading to product process defects.

[0006] Third, the lack of interlocking permissions among multiple pump sets weakens the ability to prevent accidental operation. When multiple pump sets are started simultaneously or in a queue, the existing solution lacks a permission isolation and start-up authorization mechanism, which can easily lead to problems such as human error, program command conflicts, and unauthorized pump start-up. Once the timing of multi-stage pumps is disordered, it can cause vacuum fluctuations and furnace atmosphere leakage at best, and directly lead to equipment damage and safety accidents at worst.

[0007] Fourth, the control logic is rigid and lacks dynamic intervention capability. Existing technical solutions all use preset fixed processes, making it impossible to add pump sets online or temporarily stop pumps during process operation. Once the start-up and shutdown process is triggered, it can only be executed according to the established logic, and cannot be dynamically adjusted according to actual conditions such as changes in on-site load or abnormal equipment status, resulting in a serious lack of flexible control capability.

[0008] To address the industry pain points that existing technologies cannot overcome, there is an urgent need in this field for a graded pump start-stop control system and method that can be based on atmosphere mode switching and multi-dimensional steady-state detection of the pump unit itself, and has the ability to adaptively distinguish operating conditions, interlock multiple pump permissions, and provide online dynamic intervention, so as to fill the gap in this technical field. Summary of the Invention

[0009] To address the technical problems of load start-up, vacuum fluctuations, frequent misoperations, and control rigidity in existing multi-stage pump group control of vacuum thermal equipment, which are caused by single parameter determination, lack of operating condition differentiation, lack of authorization interlocking, and lack of dynamic intervention, this invention proposes a graded pump group start-up and shutdown control system and method based on atmosphere mode switching and token interlocking.

[0010] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a graded pump group start-stop control system based on atmosphere mode switching and token interlocking, including a human-machine interaction configuration module and a PLC controller that is communicatively connected to the human-machine interaction configuration module. The output terminal of the PLC controller is connected to multiple pump groups; each pump group includes a mechanical pump and a Roots pump. The human-machine interaction configuration module is used to set the process atmosphere mode and complete the pre-selection configuration of the pump group; the process atmosphere mode includes a low vacuum mode and a high vacuum mode, and at least two pump groups are selected in the pre-selection configuration of the pump group. The pump status acquisition module of the PLC controller is used to collect the operating status information of each pump under test in real time. The operating status information of the pump group includes at least the pump motor starter status signal, the pump contactor status signal, the pump operating current, and the absolute pressure inside the furnace corresponding to the pump group. The PLC controller is configured to filter pumps that meet the operating conditions based on the identified current process atmosphere mode and pump group operating status information, generate a pump group start-up waiting queue, and control the pump groups to start one by one through a single token exclusive interlock mechanism.

[0011] Furthermore, the human-machine interaction configuration module includes an industrial touch screen. The graphical user interface of the industrial touch screen is equipped with multiple touch selection buttons. Each of the multiple touch selection buttons establishes a one-to-one mapping relationship with a preset variable address in the PLC controller through an industrial Ethernet, which is used to generate trigger signals. The variables include at least a process atmosphere mode variable and a pump group pre-selection variable. The trigger signal corresponds to at least the setting of the process atmosphere mode and the pump group pre-selection configuration.

[0012] Furthermore, the single-token exclusive interlocking mechanism is as follows: during system operation, only a unique start token is generated, and at the same time, only the single pump group holding the start token is allowed to perform the start action, while the other pump groups in the start waiting queue remain locked and in standby state.

[0013] Furthermore, "having the operating conditions" means that the pump set is configured in the pre-selected state, and the on / off status signal of the normally open contact of the pump set motor starter is characterized as closed. When the process atmosphere mode identification result is low vacuum mode, the mechanical pump set that is configured as pre-selected and whose normally open contact of the pump set motor starter is collected is characterized as closed, and a pump set start-up waiting queue is generated. When the process atmosphere mode identification result is high vacuum mode, the on / off status signal of the normally open contact of the pump motor starter, which is configured as a pre-selected state and is characterized as a closed mechanical pump group and Roots pump group, is used to generate a pump group start-up waiting queue.

[0014] Furthermore, the PLC controller is also connected to a fault early warning unit for collecting pump group fault alarm signals; The PLC controller integrates a token circulation control unit, which allocates, circulates, and locks pump start tokens based on the pump group's operating status information and pump group fault alarm signals.

[0015] Furthermore, the token transfer control unit is pre-set with three steady-state determination conditions, and the token transfer control unit executes token transfer based on the three steady-state determination conditions; The triple steady-state determination criteria include: Condition 1: The on / off state signal of the normally open contact of the contactor acquired by the PLC controller is characterized as closed and lasts for a certain period of time; Condition 2: The starting current of the pump group collected by the PLC controller remains stable within the preset current operating range for a certain period of time. Condition 3: The normally open contact signal of the pump motor starter acquired by the PLC controller has not been opened for a period of time.

[0016] Furthermore, the token transfer control unit's activation token transfer rules are as follows: The first pump unit in the start-up queue obtains the start token and then performs the start-up action. If all three steady-state conditions are met within a certain time, the current start token is revoked and the start token is shifted sequentially to the next pump group to be started in the start waiting queue. If any of the three steady-state determination conditions is not met, the start token is immediately released and the start token is moved sequentially to the next pump group to be started in the start waiting queue. At the same time, the signal to release the start token is transmitted to the audible and visual alarm device connected to the PLC controller and the host computer to trigger the audible and visual alarm device to respond and display the faulty pump group number and fault type on the host computer interface. When the process atmosphere mode is switched from low vacuum mode to high vacuum mode, and the absolute pressure inside the furnace drops below the preset pressure threshold, the system retains the original mechanical pump group operation queue, releases the start token, and redistributes the start token to the Roots pump group start queue.

[0017] Furthermore, the conditions for operation are met, meaning that the pump set is configured in the pre-selected state, and the on / off status signal of the normally open contact of the pump set motor starter collected by the PLC controller is closed, and no fault alarm signal of the pump set is collected. When the process atmosphere mode identification result is low vacuum mode, mechanical pumps that are configured as pre-selected, whose on / off status signals of the normally open contacts of the pump motor starter are closed and no fault alarm signals are collected are generated into a pump start waiting queue. When the process atmosphere mode identification result is high vacuum mode, mechanical pump groups and Roots pump groups that are configured in the pre-selection state, whose on / off status signals of the normally open contacts of the pump group motor starter are closed and no fault alarm signals are collected are generated into a pump group start-up waiting queue.

[0018] A method for starting and stopping a graded pump group based on atmosphere mode switching and token interlocking, employing the aforementioned graded pump group start and stop control system based on atmosphere mode switching and token interlocking, includes the following steps: Step S1: Set the process atmosphere mode and complete the pre-selection configuration of the pump group through the human-machine interaction configuration module. The process atmosphere mode includes low vacuum mode and high vacuum mode. The pump group status acquisition module collects the operating status information of each pump group under test in real time and uploads it to the PLC controller. Step S2: The PLC controller selects pumps that meet the operating conditions based on the identified current process atmosphere mode and pump group operating status information, and generates a pump group start-up waiting queue. When the process atmosphere mode identification result is low vacuum mode, the on / off state signal of the normally open contact of the pump motor starter is screened and collected to represent the closed mechanical pump group to generate a pump group start-up waiting queue. When the process atmosphere mode identification result is high vacuum mode, the on / off state signal of the normally open contact of the pump motor starter is screened and collected to represent the closed mechanical pump group and Roots pump group to generate a pump group start-up waiting queue. Step S3: The PLC controller assigns a unique start token to the pump group that is first in the pump group start waiting queue, controls the normally open contact of the contactor of that pump group to close, and executes the start operation. Step S4: Based on the preset triple steady-state judgment conditions in the PLC controller, perform the start token transfer operation; specifically, when the current pump group meets the triple steady-state judgment conditions, reclaim the start token and transfer it to the next pump group in the pump group start waiting queue. Step S5: Repeat the activation token transfer operation of step S4.

[0019] Furthermore, during the execution of steps S2-S5 above, when the process atmosphere mode identification result switches from low vacuum mode to high vacuum mode, a new start-up waiting queue is generated by adding Roots pump sets that are ready for operation, based on the existing start-up waiting queue generated by mechanical pump sets that are ready for operation.

[0020] The advantages of this invention compared to the prior art are as follows: The system and method of this invention use the set process atmosphere mode as the top-level control basis, and combine multiple judgment criteria of multi-dimensional operating status information of each pump group under test to screen pump groups that meet the operating conditions and generate a pump group start-up waiting queue. Through a single token exclusive interlocking mechanism, multiple pump groups are started in stages and one by one, and faulty pump groups and offline pump groups are automatically eliminated. Through the synergistic effect of the human-machine interaction configuration module and the PLC controller, online dynamic intervention function can be completed, realizing safe, orderly and flexible operation control of multi-stage pump groups in vacuum thermal equipment throughout the entire process. Attached Figure Description

[0021] The present invention will be further described below with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the system structure of the present invention; Figure 2 This is a flowchart illustrating the start / stop logic of the token flow in this invention. Figure 3 This is a flowchart of the pump start-up and shutdown process based on the process atmosphere mode of the present invention. Figure 4 A schematic diagram comparing the start-up and shutdown sequence of the pump set; Figure 5 This is the interface for pre-selecting and configuring pump units in the human-computer interaction configuration module of the present invention; Figure 6 This is the interface for setting the vacuum mode in the human-computer interaction configuration module of the present invention; Figure 7 This is the pump group intervention interface during the operation of the system of the present invention. Detailed Implementation

[0022] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate relative orientations or positional relationships and are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0023] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0024] like Figures 1 to 7 As shown, this invention provides a graded pump group start-stop control system based on atmosphere mode switching and token interlocking. It includes a human-machine interface configuration module and a PLC controller communicatively connected to the configuration module. The output of the PLC controller is connected to multiple pump groups. Each pump group includes a mechanical pump and a Roots pump. The mechanical pumps within each pump group together constitute a mechanical pump group, and the Roots pumps within each pump group together constitute a Roots pump group. In one embodiment, four pump groups are arranged, connected in parallel on the main pipeline of their respective vacuum systems, and can be independently switched or work collaboratively. Each pump group consists of one mechanical pump and one Roots pump connected in series.

[0025] The human-machine interaction configuration module is used for operators to set the process atmosphere mode and complete the pump group pre-selection configuration. The process atmosphere mode includes low vacuum mode and high vacuum mode. At least two pump groups must be selected in the pump group pre-selection configuration. In this embodiment, the human-machine interface configuration module includes an industrial touchscreen. The graphical user interface of the industrial touchscreen has multiple touch selection buttons. These buttons are mapped one-to-one with preset variable addresses in the PLC controller via an industrial Ethernet network (based on the Siemens S7 communication protocol) to generate trigger signals. The variables include at least a process atmosphere mode variable and a pump group pre-selection variable. The trigger signal corresponds at least to the set process atmosphere mode and pump group pre-selection configuration. The pump group status acquisition module of the PLC controller is used to collect the operating status information of each pump group under test in real time. The pump group operating status information includes at least the pump group contactor status signal, the pump group motor starter status signal, the pump group operating current, and the absolute pressure inside the furnace corresponding to the pump group. The pump group status acquisition module completes full parameter acquisition every 200ms. The PLC controller is a Siemens 1200 / 1215C / DC / DC / DC model.

[0026] In this embodiment, the normally open contacts of the pump group contactor and the normally open contacts of the pump group motor starter are respectively connected to the digital input module of the PLC controller. The digital input module provides detection power. When the normally open contacts of the pump group contactor and the normally open contacts of the pump group motor starter are closed / opened, the on / off state of the digital input module circuit is changed. The pump group status acquisition module identifies the status of the circuit and outputs the corresponding digital signal. Closed is "1" and open is "0". This is used to determine whether the pump group contactor is engaged and whether the pump group motor starter is working normally. This helps to determine whether the pump group is properly energized and whether the mechanical actuator is in place.

[0027] The analog input module of the PLC controller is electrically connected to the secondary side of a current transformer and a vacuum gauge. The primary side of the current transformer is connected to the power phase line of the pump motor to collect the pump operating current. The vacuum gauge is sealed and inserted into the furnace body to collect the absolute pressure inside the furnace. The current transformer is an Acrel AKH-0.66 I 20I 50 / 5; the vacuum gauge is a Ruibao PCG554.

[0028] The digital input module and the analog input module together constitute the pump group status acquisition module.

[0029] The PLC controller is configured to filter pumps that meet the operating conditions based on the identified current process atmosphere mode and pump group operating status information, generate a pump group start-up waiting queue, and control the pump groups to start one by one through a single token exclusive interlock mechanism.

[0030] In this embodiment, the operating conditions are defined as the pump set being configured in a pre-selected state, and the on / off state signal of the normally open contact of the pump set starter being collected as closed. When the process atmosphere mode identification result is low vacuum mode (1200Pa-atmosphere pressure), the mechanical pump set whose pre-selected state is selected and whose normally open contact of the pump set motor starter is collected is characterized as closed, and a pump set start-up waiting queue is generated. When the process atmosphere mode identification result is high vacuum mode (less than 1200Pa), the on / off status signal of the normally open contact of the pump set motor starter, which is configured as a pre-selected state and is characterized as a closed mechanical pump set and Roots pump set, generates a pump set start-up waiting queue.

[0031] In this embodiment, the single token exclusive interlocking mechanism is as follows: only a unique start token is generated during system operation, and only the single pump group holding the start token is allowed to perform the start action at the same time. The other pump groups in the start waiting queue remain locked and in standby state, thus eliminating the problem of multiple pump groups starting simultaneously and cross-operating condition mismatch start from the root.

[0032] In this embodiment, the PLC controller is also communicatively connected to a fault early warning unit for collecting pump group fault alarm signals; The PLC controller integrates a token circulation control unit, which allocates, circulates, and locks pump start tokens based on the pump group's operating status information and pump group fault alarm signals.

[0033] The token transfer control unit has three preset steady-state determination conditions. The control unit executes token transfer based on these conditions; that is, all three steady-state determination conditions must be met and maintained for a certain period of time (e.g., 0-10s, preferably 5s) before the pump unit can be determined to have entered a stable operating state, and token transfer can be executed. The three steady-state determination conditions include: Condition 1: The on / off state signal of the normally open contact of the contactor acquired by the PLC controller is characterized as closed and lasts for a certain period of time; Condition 2: The starting current (also known as the inrush current) of the pump set collected by the PLC controller remains stable within the preset current operating range for a certain period of time; the preset current operating range is 80%~100% of the rated current of the pump set. Condition 3: The normally open contact signal of the pump motor starter collected by the PLC controller does not open within a certain period of time, that is, no tripping occurs.

[0034] The token transfer control unit's activation token transfer rules are as follows: The first pump unit in the start-up queue obtains the start token and then performs the start-up action. If all three steady-state determination conditions are met within a certain period of time, the pump unit is determined to have entered a stable operating state. The system reclaims the current start token and moves the start token sequentially to the next pump unit waiting to be started in the start waiting queue. If any of the three steady-state determination conditions is not met, the start token is immediately released and the start token is moved sequentially to the next pump group to be started in the start waiting queue. At the same time, the signal to release the start token is transmitted to the audible and visual alarm device connected to the PLC controller and the host computer to trigger the audible and visual alarm device to respond and display the faulty pump group number and fault type on the host computer interface. When the process atmosphere mode is switched from low vacuum mode to high vacuum mode, and the absolute pressure inside the furnace drops below the preset pressure threshold (e.g., less than 1200 Pa, preferably less than 800 Pa), the system retains the original mechanical pump group running queue, releases the start token, and redistributes the start token to the Roots pump group start queue.

[0035] In another embodiment, the operating conditions are defined as follows: the pump set is configured in a pre-selected state, and the on / off state signal of the normally open contact of the pump set motor starter collected by the PLC controller is characterized as closed, and no fault alarm signal of the pump set is collected. When the process atmosphere mode identification result is low vacuum mode, mechanical pumps that are configured as pre-selected, whose on / off status signals of the normally open contacts of the pump motor starter are closed and no fault alarm signals are collected are generated into a pump start waiting queue. When the process atmosphere mode identification result is high vacuum mode, mechanical pump groups and Roots pump groups configured in the pre-selection state, whose on / off state signals of the normally open contacts of the pump group motor starter are closed and no fault alarm signals are collected are generated to form a pump group start-up waiting queue. The system of this invention uses the process atmosphere mode set by the operator as the top-level control basis, and combines multiple judgment criteria of multi-dimensional operating status information of each pump group under test to screen pump groups that meet the operating conditions and generate a pump group start-up waiting queue. Through a single token exclusive interlocking mechanism, multiple pump groups are started in stages and one by one, and faulty pump groups and offline pump groups are automatically eliminated. Through the coordinated action of the human-machine interaction configuration module and the PLC controller, online dynamic intervention function can be completed to realize safe, orderly and flexible operation control of multi-stage pump groups in vacuum thermal equipment throughout the entire process.

[0036] This invention combines pump operating status information, including at least the pump contactor status signal, the pump motor starter status signal, the pump operating current, and the absolute pressure inside the furnace corresponding to the pump, to achieve multi-dimensional joint detection. It also sets constraints such as steady-state duration and acquisition cycle to accurately identify the pump's true operating conditions, effectively avoiding the "false steady-state" problem caused by instantaneous signal interference. This fundamentally eliminates faults such as multi-stage pump starting under load, current surges, phase loss, overload, and short circuits, significantly reducing equipment wear and extending the overall service life of the pump set.

[0037] This invention addresses the process characteristics of alternating high and low vacuum operation in vacuum thermal equipment such as high-temperature graphitization furnaces and carbon-ceramic deposition furnaces. The PLC controller, based on the operator-defined process atmosphere mode and pump status information, selects pumps that meet the operating conditions and generates a pump start-up queue. In low vacuum mode, the mechanical pump is activated; in high vacuum mode, the Roots pump is activated in conjunction with the system, provided the preset pressure threshold is met. This completely solves the defects of redundant pump start-up in low vacuum and insufficient power in high vacuum. It maintains a stable vacuum environment and atmosphere purity within the furnace throughout the process, reducing process defects and effectively improving product yield.

[0038] This invention's system controls the startup of pump units one by one through a single-token exclusive interlock mechanism, effectively avoiding risks such as simultaneous startup of multiple pump units, skip-stage startup, and human error. When a single pump unit experiences an operational anomaly, the system immediately releases the startup token and accurately reports the fault, preventing the fault from spreading without halting the entire process. This significantly improves equipment operational safety and system anti-interference capabilities.

[0039] During normal operation of the vacuum thermal equipment, the human-machine interface configuration module and PLC controller work together to enable online, uninterrupted addition of pump units and temporary pump shutdown operations. Operators can flexibly adjust the number of pump units in operation according to the on-site vacuum load and production conditions, perfectly adapting to complex and ever-changing on-site production needs.

[0040] This invention utilizes a human-machine interface configuration module to configure the addition or removal of pump units and the switching of process atmosphere modes. The control logic is simple and clear, and fault locations are intuitively displayed, significantly improving fault location and daily maintenance efficiency. It can be widely applied to various multi-stage pump unit equipment that alternates between high and low vacuum.

[0041] This invention provides a staged pump group start-stop control method based on atmosphere mode switching and token interlocking. Employing the aforementioned staged pump group start-stop control system based on atmosphere mode switching and token interlocking, the method includes the following steps: Step S1: Set the process atmosphere mode and complete the pre-selection configuration of the pump group through the machine interaction configuration module. The process atmosphere mode includes low vacuum mode and high vacuum mode. The pump group status acquisition module collects the operating status information of each pump group under test in real time and uploads it to the PLC controller. Step S2: The PLC controller selects pumps that meet the operating conditions based on the identified current process atmosphere mode and pump group operating status information, and generates a pump group start-up waiting queue. When the process atmosphere mode identification result is low vacuum mode, the on / off state signal of the normally open contact of the pump motor starter is screened and collected to represent the closed mechanical pump group to generate a pump group start-up waiting queue. When the process atmosphere mode identification result is high vacuum mode, the on / off state signal of the normally open contact of the pump motor starter is screened and collected to represent the closed mechanical pump group and Roots pump group to generate a pump group start-up waiting queue. Step S3: The PLC controller assigns a unique start token to the pump group that is first in the pump group start waiting queue, controls the normally open contact of the contactor of that pump group to close, and executes the start operation. Step S4: Based on the preset triple steady-state judgment conditions in the PLC controller, execute the start token transfer operation; specifically, when the current pump group meets the triple steady-state judgment conditions, the start token is retrieved and transferred to the next pump group in the pump group start waiting queue; when a pump group does not meet the triple steady-state judgment conditions, the start token of that pump group is released and transferred sequentially to the next pump group in the pump group start waiting queue, and at the same time, the signal of releasing the start token is transmitted to the audible and visual alarm device connected to the PLC controller and the host computer respectively to trigger the audible and visual alarm device to respond, and display the faulty pump group number and fault type on the host computer interface.

[0042] Step S5: Repeat the activation token transfer operation of step S4.

[0043] During the execution of steps S2-S5 above, when the process atmosphere mode identification result switches from low vacuum mode to high vacuum mode, a new start-up waiting queue is generated by adding Roots pump sets that meet the operating conditions, based on the existing start-up waiting queue generated by the mechanical pump sets that meet the operating conditions. Specifically, the newly added Roots pump sets that meet the operating conditions are sequentially placed after the start-up waiting queues generated by all existing mechanical pumps that meet the operating conditions.

[0044] Regarding the specific structure of this invention, it should be noted that the connection relationships between the various component modules used in this invention are definite and achievable. Except as specifically described in the embodiments, their specific connection relationships can bring about corresponding technical effects and solve the technical problems proposed by this invention without relying on the execution of corresponding software programs. The models of the components, modules, and specific components appearing in this invention, the connection methods between them, and the conventional usage methods and expected technical effects brought about by the above technical features, unless specifically described, are all publicly disclosed content in patents, journal articles, technical manuals, technical dictionaries, and textbooks that can be obtained by those skilled in the art before the application date, or belong to conventional technology, common knowledge, and other existing technologies in this field. There is no need to elaborate, which makes the technical solution provided in this case clear, complete, and achievable, and can reproduce or obtain corresponding physical products based on this technical means.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A graded pump group start-stop control system based on atmosphere mode switching and token interlocking, characterized in that, include: The human-machine interaction configuration module and the PLC controller are communicatively connected to the human-machine interaction configuration module. The output terminal of the PLC controller is connected to multiple pump groups. Each pump group includes a mechanical pump and a Roots pump. The mechanical pumps in each pump group together constitute a mechanical pump group, and the Roots pumps in each pump group together constitute a Roots pump group. The human-machine interaction configuration module is used to set the process atmosphere mode and complete the pre-selection configuration of the pump group; the process atmosphere mode includes a low vacuum mode and a high vacuum mode, and at least two pump groups are selected in the pre-selection configuration of the pump group. The pump status acquisition module of the PLC controller is used to collect the operating status information of each pump under test in real time. The operating status information of the pump group includes at least the pump motor starter status signal, the pump contactor status signal, the pump operating current, and the absolute pressure inside the furnace corresponding to the pump group. The PLC controller is configured to filter pumps that meet the operating conditions based on the identified current process atmosphere mode and pump group operating status information, generate a pump group start-up waiting queue, and control the pump groups to start one by one through a single token exclusive interlock mechanism.

2. The graded pump group start-stop control system based on atmosphere mode switching and token interlocking as described in claim 1, characterized in that, The human-machine interaction configuration module includes an industrial touch screen. The graphical user interface of the industrial touch screen is equipped with multiple touch selection buttons. Each of the multiple touch selection buttons establishes a one-to-one mapping relationship with a preset variable address in the PLC controller through an industrial Ethernet, which is used to generate trigger signals. The variables include at least a process atmosphere mode variable and a pump group pre-selection variable. The trigger signal corresponds to at least the setting of the process atmosphere mode and the pump group pre-selection configuration.

3. The graded pump group start-stop control system based on atmosphere mode switching and token interlocking according to claim 1, characterized in that, The single token exclusive interlocking mechanism is as follows: during system operation, only a unique start token is generated, and at the same time, only the single pump group holding the start token is allowed to perform the start action, while the other pump groups in the start waiting queue remain locked and in standby state.

4. The graded pump group start-stop control system based on atmosphere mode switching and token interlocking according to claim 1, characterized in that, The conditions for operation are met, meaning that the pump set is configured in the pre-selected state and the on / off status signal of the normally open contact of the pump set motor starter is characterized as closed. When the process atmosphere mode identification result is low vacuum mode, the mechanical pump set that is configured as pre-selected and whose normally open contact of the pump set motor starter is collected is characterized as closed, and a pump set start-up waiting queue is generated. When the process atmosphere mode identification result is high vacuum mode, the on / off status signal of the normally open contact of the pump motor starter, which is configured as a pre-selected state and is characterized as a closed mechanical pump group and Roots pump group, is used to generate a pump group start-up waiting queue.

5. The graded pump group start-stop control system based on atmosphere mode switching and token interlocking according to claim 1, characterized in that, The PLC controller is also connected to a fault early warning unit for collecting pump group fault alarm signals. The PLC controller integrates a token circulation control unit, which allocates, circulates, and locks pump start tokens based on the pump group's operating status information and pump group fault alarm signals.

6. The graded pump group start-stop control system based on atmosphere mode switching and token interlocking according to claim 5, characterized in that, The token transfer control unit has three preset steady-state determination conditions, and the token transfer control unit executes token transfer based on the three steady-state determination conditions; The triple steady-state determination criteria include: Condition 1: The on / off state signal of the normally open contact of the contactor acquired by the PLC controller is characterized as closed and lasts for a certain period of time; Condition 2: The starting current of the pump group collected by the PLC controller remains stable within the preset current operating range for a certain period of time. Condition 3: The normally open contact signal of the pump motor starter acquired by the PLC controller has not been opened for a period of time.

7. The graded pump group start-stop control system based on atmosphere mode switching and token interlocking according to claim 6, characterized in that, The token transfer control unit's activation token transfer rules are as follows: The first pump unit in the start-up queue obtains the start token and then performs the start-up action. If all three steady-state conditions are met within a certain time, the current start token is revoked and the start token is shifted sequentially to the next pump group to be started in the start waiting queue. If any of the three steady-state determination conditions is not met, the start token is immediately released and the start token is moved sequentially to the next pump group to be started in the start waiting queue. At the same time, the signal to release the start token is transmitted to the audible and visual alarm device connected to the PLC controller and the host computer to trigger the audible and visual alarm device to respond and display the faulty pump group number and fault type on the host computer interface. When the process atmosphere mode is switched from low vacuum mode to high vacuum mode, and the absolute pressure inside the furnace drops below the preset pressure threshold, the system retains the original mechanical pump group operation queue, releases the start token, and redistributes the start token to the Roots pump group start queue.

8. The graded pump group start-stop control system based on atmosphere mode switching and token interlocking according to claim 5, characterized in that, Operating conditions are met when the pump set is configured in the pre-selected state, the on / off status signal of the normally open contact of the pump set motor starter collected by the PLC controller is closed, and no fault alarm signal of the pump set is collected. When the process atmosphere mode identification result is low vacuum mode, mechanical pumps that are configured as pre-selected, whose on / off status signals of the normally open contacts of the pump motor starter are closed and no fault alarm signals are collected are generated into a pump start waiting queue. When the process atmosphere mode identification result is high vacuum mode, mechanical pump groups and Roots pump groups that are configured in the pre-selection state, whose on / off status signals of the normally open contacts of the pump group motor starter are closed and no fault alarm signals are collected are generated into a pump group start-up waiting queue.

9. A method for starting and stopping a graded pump group based on atmosphere mode switching and token interlocking, employing the graded pump group start and stop control system based on atmosphere mode switching and token interlocking as described in any one of claims 1-7, characterized in that, Includes the following steps: Step S1: Set the process atmosphere mode and complete the pre-selection configuration of the pump group through the human-machine interaction configuration module. The process atmosphere mode includes low vacuum mode and high vacuum mode. The pump group status acquisition module collects the operating status information of each pump group under test in real time and uploads it to the PLC controller. Step S2: The PLC controller selects pumps that meet the operating conditions based on the identified current process atmosphere mode and pump group operating status information, and generates a pump group start-up waiting queue. When the process atmosphere mode identification result is low vacuum mode, the on / off state signal of the normally open contact of the pump motor starter is screened and collected to represent the closed mechanical pump group to generate a pump group start-up waiting queue. When the process atmosphere mode identification result is high vacuum mode, the on / off state signal of the normally open contact of the pump motor starter is screened and collected to represent the closed mechanical pump group and Roots pump group to generate a pump group start-up waiting queue. Step S3: The PLC controller assigns a unique start token to the pump group that is first in the pump group start waiting queue, controls the normally open contact of the contactor of that pump group to close, and executes the start operation. Step S4: Based on the preset triple steady-state judgment conditions in the PLC controller, perform the start token transfer operation; specifically, when the current pump group meets the triple steady-state judgment conditions, reclaim the start token and transfer it to the next pump group in the pump group start waiting queue. Step S5: Repeat the activation token transfer operation of step S4.

10. A method for controlling the start-stop of a graded pump group based on atmosphere mode switching and token interlocking as described in claim 8, characterized in that, During the execution of steps S2-S5 above, when the process atmosphere mode identification result switches from low vacuum mode to high vacuum mode, a new start-up waiting queue is generated by adding Roots pump sets that are ready for operation, based on the existing start-up waiting queue generated by mechanical pump sets that are ready for operation.

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