Limestone homogenization trolley control system and method based on PLC control

Abstract

The application discloses a kind of based on PLC control's limestone homogenization trolley control system and method, including homogenization belt;Homogenization trolley;Multiple segment detection sensors are arranged along the homogenization belt;Control unit, including PLC controller, and upper monitoring system;Wherein, the PLC controller is configured as: according to the user instruction selectively activates the detection sensor signal of corresponding segment;According to activated segment detection sensor signal, the homogenization trolley is automatically operated in corresponding segment and returns;When detecting that the homogenization trolley exceeds predetermined travel range or operation timeout, trigger alarm and stop the motor.The application is automatically operated in specified segment and returns by PLC intelligent control homogenization trolley, and has the function of over-limit protection, solve the problem that traditional system is poor in reliability, low efficiency, realize that failure rate is greatly reduced and maintenance cost is significantly reduced.

Description

Technical Field

[0001] This invention relates to the field of industrial automation control technology, and in particular to a control system and method for a limestone homogenization trolley based on PLC control. Background Technology

[0002] Limestone homogenization trolley systems are widely used in industries such as cement and metallurgy. Existing homogenization systems achieve limestone homogenization through segmented control, relying on complex electrical components and manual intervention, which presents a series of problems. Traditional homogenization structures mainly consist of a homogenization belt and a homogenization trolley. The trolley travels back and forth on the belt to complete the homogenization work, and segmented control utilizes multiple discrete components such as contactors, relays, and limit switches. However, this approach has several significant drawbacks.

[0003] First, frequent manual intervention increases the workload for workers and poses significant safety hazards when switching operating sections. For example, switching sections requires workers to manually operate the changeover switch and replace the power plug, a process that is both time-consuming and risky. Second, the complex and numerous mechanical limit switches and contactors increase the system's failure rate and correspondingly increase maintenance costs. Furthermore, frequent use of mechanical switches and plugs shortens equipment lifespan, and poor contact further impacts system stability and reliability.

[0004] Finally, the traditional manual segment switching control method has a low degree of automation and cannot meet the needs of multi-segment intelligent switching and remote centralized control, thus affecting the efficiency of limestone homogenization. Therefore, there is an urgent need for a more intelligent, reliable, and safe limestone homogenization control system to replace the existing system in order to improve production efficiency and reduce labor costs. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the existing technology. To achieve the above objective, a PLC-based limestone homogenization trolley control system and method are adopted to solve the problems mentioned in the background technology.

[0006] A PLC-based limestone homogenization trolley control system includes:

[0007] Homogenization belt; A homogenizing trolley is positioned above the homogenizing belt, and the homogenizing trolley is driven by a motor; Multiple segment detection sensors are arranged along the homogenization belt to detect the position of the homogenization trolley; The control unit includes a PLC controller and a host monitoring system. The host monitoring system is used to receive user instructions and send them to the PLC controller. The PLC controller is used to receive signals from the segment detection sensor and control the operation of the motor according to the user instructions. The PLC controller is configured as follows: The detection sensor signal of the corresponding segment is selectively activated according to the user instruction; The homogenization trolley is controlled to automatically travel back and forth within the corresponding segment based on the signal from the activated segment detection sensor. When the homogenizing trolley is detected to have exceeded the predetermined travel range or exceeded the operating time, an alarm is triggered and the motor is stopped.

[0008] As a further aspect of the present invention: the segment detection sensor includes a forward proximity switch and a reverse proximity switch respectively installed in the first transmission segment, the second transmission segment, and the third transmission segment of the homogenization belt, as well as a forward limit switch and a reverse limit switch.

[0009] As a further aspect of the present invention: the upper-level monitoring system is a DCS system, which is equipped with a segment selection unit and an over-limit alarm unit.

[0010] As a further aspect of the present invention: the power switching unit includes multiple AC contactors, and the PLC controller controls the on / off state of the AC contactors through intermediate relays for switching the motor in forward and reverse directions and for power isolation in fixed-point mode.

[0011] As a further aspect of the present invention: the power switching unit includes: The first AC contactor is used to control the forward power supply path of the motor; The second AC contactor is used to control the reverse power supply path of the motor; The third AC contactor is used to provide an independent power path in the fixed-point equalization mode.

[0012] As a further aspect of the present invention: the motor is a three-phase asynchronous motor, and a thermal relay is provided in its main circuit. The overload protection threshold of the thermal relay is set to 1.0 to 1.2 times the rated current of the motor.

[0013] As a further aspect of the present invention: the forward proximity switch and the reverse proximity switch are inductive proximity switches with a detection distance of 8mm and a response time of less than or equal to 1ms.

[0014] As a further aspect of the present invention, the PLC controller and the host monitoring system are connected via an industrial communication bus or I / O signal line.

[0015] The second aspect of the technical solution: A control method for a PLC-based limestone homogenization trolley control system as described in any of the above claims, comprising the following steps: The target's operating mode is selected through the supervisory control system; The PLC controller parses the operating mode instruction and performs a priority determination; The PLC controller controls the power supply path of the motor according to the selected mode and outputs motor start / stop and forward / reverse signals; The PLC controller monitors the status of the segment detection sensor in real time. If it detects an over-limit or operation timeout without triggering a signal, it sends an alarm to the upper-level monitoring system and executes an emergency shutdown procedure.

[0016] As a further aspect of the present invention, the criterion for judging running timeout is set to 120% of the theoretical running time for a single trip.

[0017] Compared with the prior art, the present invention has the following technical advantages: The above technical solution involves a PLC controller receiving instructions from a higher-level monitoring system and selectively activating signals from segment detection sensors located along the homogenization conveyor belt. Based on this, the motor drives the homogenization trolley to automatically reciprocate within designated segments. The system automatically alarms and shuts down when the trolley exceeds its travel range or times out. This solution solves the problems of traditional systems, such as reliance on manual operation, low reliability, and high failure rate. It significantly reduces equipment failure frequency, lowers maintenance costs, and greatly improves the efficiency of segment switching and homogenization operations. Attached Figure Description

[0018] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the structure of the homogenization vehicle control system according to an embodiment of this application; Figure 2 This is a schematic diagram of the connection relationship of the homogenization trolley control system according to an embodiment of this application. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Please refer to Figure 1 and Figure 2 In this embodiment of the invention, a PLC-controlled limestone homogenization cart control system includes: The homogenizing belt has multiple discharge ports along its length. A homogenizing trolley is positioned above the homogenizing belt, and the homogenizing trolley is driven by a motor; Multiple segment detection sensors are arranged along the homogenization belt to detect the position of the homogenization trolley; The control unit includes a PLC controller and a host monitoring system. The host monitoring system is used to receive user instructions and send them to the PLC controller. The PLC controller is used to receive signals from the segment detection sensor and control the operation of the motor according to the user instructions. The multiple segment detection sensors are installed in segments along the length of the homogenizing belt, with a set of sensors set in each segment to accurately locate the running range of the trolley within that segment; The PLC controller collects the switching signals of each sensor in real time through the digital input module, and determines the current position and running direction of the trolley according to the preset logic. The PLC controller is configured as follows: The detection sensor signal of the corresponding segment is selectively activated according to the user instruction; Specifically, when a user selects a certain operating segment in the upper-level monitoring system, the PLC only includes the forward and reverse proximity switches and limit switches corresponding to that segment in the monitoring logic, and temporarily shields the sensor signals of other segments. The homogenization trolley is controlled to automatically travel back and forth within the corresponding segment based on the signal from the activated segment detection sensor. The reciprocating operation control drives the intermediate relay through the PLC output module, which in turn controls the AC contactor to switch the motor between forward and reverse rotation. When the homogenizing trolley is detected to have exceeded the predetermined travel range or exceeded the operating time, an alarm is triggered and the motor is stopped.

[0021] The criterion for determining whether the travel range exceeds the predetermined travel range is: if the trolley triggers the positive or reverse limit switch of the segment during operation, it is considered to have exceeded the limit. The criteria for determining the timeout are as follows: if the time it takes for the trolley to travel from one end to the other exceeds 120% of the theoretical running time of that segment, the PLC's internal timer overflows and triggers the timeout logic.

[0022] In this embodiment, the segment detection sensor includes a forward proximity switch and a reverse proximity switch respectively installed in the first transmission segment, the second transmission segment, and the third transmission segment of the homogenization belt, as well as a forward limit switch and a reverse limit switch.

[0023] In this embodiment, the upper-level monitoring system is a DCS system, which is equipped with a segment selection unit and an over-limit alarm unit.

[0024] In this embodiment, the power switching unit includes multiple AC contactors. The PLC controller controls the on / off state of the AC contactors through intermediate relays for switching the motor in forward and reverse directions and for power isolation in fixed-point mode.

[0025] In this embodiment, the power switching unit includes: The first AC contactor is used to control the forward power supply path of the motor; The second AC contactor is used to control the reverse power supply path of the motor; The third AC contactor is used to provide an independent power path in the fixed-point equalization mode.

[0026] In this embodiment, the motor is a three-phase asynchronous motor, and a thermal relay is provided in its main circuit. The overload protection threshold of the thermal relay is set to 1.0 to 1.2 times the rated current of the motor.

[0027] In this embodiment, the forward proximity switch and the reverse proximity switch are inductive proximity switches with a detection distance of 8mm and a response time of less than or equal to 1ms.

[0028] In this embodiment, the PLC controller and the host monitoring system are connected via an industrial communication bus or I / O signal line.

[0029] Example 2: Based on the above system scheme, in the specific implementation, the homogenization trolley drive motor adopts a three-phase asynchronous motor (power 7.5kW, rated current 15A), the main circuit is configured with 3 AC contactors (model LC1-D09) to control 1-3 stages of forward and reverse rotation and fixed point mode respectively, and the thermal relay (model LRD-35) is set with an overload protection threshold of 1.1 times the rated current; the PLC module is a Siemens S7-200, the input port is connected to 6 inductive proximity switches (detection distance 8mm, response time ≤1ms), and the output port controls the contactor coil through an intermediate relay (model MY4N).

[0030] Example 3: Based on the above system solution, the specific implementation method is as follows: When the DCS selects the "full range" mode, the PLC executes the following logic: (1) The homogenization trolley starts forward from its current position, and automatically reverses after triggering the 3-stage reversing proximity switch; (2) When the reverse operation reaches the first stage forward proximity switch, it reverses direction again to form a cycle; (3) If the limit signal is not detected during the running timeout (set to 120% of the theoretical single-trip time), the PLC controller will be triggered to alarm and stop the machine.

[0031] The second aspect of the technical solution: A control method for a PLC-based limestone homogenization trolley control system as described in any of the above claims, comprising the following steps: The target's operating mode is selected through the supervisory control system; The PLC controller parses the operating mode instruction and performs a priority determination; The PLC controller controls the power supply path of the motor according to the selected mode and outputs motor start / stop and forward / reverse signals; The PLC controller monitors the status of the segment detection sensor in real time. If it detects an over-limit or operation timeout without triggering a signal, it sends an alarm to the upper-level monitoring system and executes an emergency shutdown procedure.

[0032] Beneficial effects: Validation data: (1) Reduced failure rate: Compared with the original system, the frequency of electrical component failures decreased from an average of 3.2 times per month to 0.5 times; (2) Maintenance costs: Annual maintenance costs were reduced by 62%, mainly due to the extended lifespan of proximity switches (the original lifespan of limit switches was 6 months, while the lifespan of proximity switches is now ≥3 years). (3) Operation efficiency: The time for switching between segments is reduced from 5-8 minutes for manual operation to within 6 seconds for automatic execution.

[0033] In this embodiment, the data table showing the improvement in quantization performance is as follows:

[0034] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention. The scope of the invention is defined by the appended claims and their equivalents, all of which should be included within the scope of protection of the invention.

Claims

1. A PLC-based limestone homogenization trolley control system, characterized in that, include: Homogenization belt; A homogenizing trolley is positioned above the homogenizing belt, and the homogenizing trolley is driven by a motor; Multiple segment detection sensors are arranged along the homogenization belt to detect the position of the homogenization trolley; The control unit includes a PLC controller and a host monitoring system. The host monitoring system is used to receive user instructions and send them to the PLC controller. The PLC controller is used to receive signals from the segment detection sensor and control the operation of the motor according to the user instructions. The PLC controller is configured as follows: The detection sensor signal of the corresponding segment is selectively activated according to the user instruction; The homogenization trolley is controlled to automatically travel back and forth within the corresponding segment based on the signal from the activated segment detection sensor. When the homogenizing trolley is detected to have exceeded the predetermined travel range or exceeded the operating time, an alarm is triggered and the motor is stopped.

2. The limestone homogenization trolley control system based on PLC control according to claim 1, characterized in that, The segment detection sensor includes a forward proximity switch and a reverse proximity switch respectively installed in the first transmission segment, the second transmission segment, and the third transmission segment of the homogenization belt, as well as a forward limit switch and a reverse limit switch.

3. The limestone homogenization trolley control system based on PLC control according to claim 1, characterized in that, The upper-level monitoring system is a DCS system, which is equipped with a segment selection unit and an over-limit alarm unit.

4. The limestone homogenization trolley control system based on PLC control according to claim 1, characterized in that, The power switching unit includes multiple AC contactors. The PLC controller controls the on / off state of the AC contactors through intermediate relays for switching the motor in forward and reverse directions and for power isolation in fixed-point mode.

5. The limestone homogenization trolley control system based on PLC control according to claim 4, characterized in that, The power switching unit includes: The first AC contactor is used to control the forward power supply path of the motor; The second AC contactor is used to control the reverse power supply path of the motor; The third AC contactor is used to provide an independent power path in the fixed-point equalization mode.

6. The limestone homogenization trolley control system based on PLC control according to claim 1, characterized in that, The motor is a three-phase asynchronous motor, and a thermal relay is installed in its main circuit. The overload protection threshold of the thermal relay is set to 1.0 to 1.2 times the rated current of the motor.

7. The limestone homogenization trolley control system based on PLC control according to claim 2, characterized in that, The forward and reverse proximity switches are inductive proximity switches with a detection distance of 8mm and a response time of less than or equal to 1ms.

8. The limestone homogenization trolley control system based on PLC control according to claim 1, characterized in that, The PLC controller is connected to the host monitoring system via an industrial communication bus or I / O signal lines.

9. A control method for a PLC-based limestone homogenization trolley control system as described in any one of claims 1 to 8, characterized in that, Includes the following steps: The target's operating mode is selected through the supervisory control system; The PLC controller parses the operating mode instruction and performs a priority determination; The PLC controller controls the power supply path of the motor according to the selected mode and outputs motor start / stop and forward / reverse signals; The PLC controller monitors the status of the segment detection sensor in real time. If it detects an over-limit or operation timeout without triggering a signal, it sends an alarm to the upper-level monitoring system and executes an emergency shutdown procedure.

10. The control method for a limestone homogenization trolley control system based on PLC control according to claim 9, characterized in that, The criterion for judging running timeout is set at 120% of the theoretical running time for a single trip.

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