PLC (Programmable Logic Controller) control system of oil pumping unit with ultra-long stroke

Abstract

The utility model discloses a PLC (programmable logic controller) control system of an ultra-long stroke oil pumping unit, which belongs to the technical field of oil pumping unit control systems and comprises a touch screen, a PLC, an RTU (remote terminal unit) module, an electrical parameter module and an oil pumping unit driving mechanism. Wherein one RS485 communication interface is connected with a pumping unit driving mechanism and an electric parameter module, the other RS485 communication interface is connected with an RTU module, and the Ethernet communication interface is connected with a touch screen. And the PLC controller completes the operation of a real-time indicator diagram and a historical indicator diagram. The system is simple in structure, reasonable in design, strong in practicability, high in reliability, strong in expansibility, flexible in network communication, low in implementation cost and convenient to popularize and use. The super-long stroke pumping unit is automatically controlled through the control system, the overall stability of the system can be improved, the flexibility and safety of the system are improved, and the failure rate is reduced. And in the aspect of stroke adjustment, automatic adjustment can be achieved, and application is convenient.

Description

Technical Field

[0001] The utility model mainly relates to the technical field of a pumping unit control system, in particular to a PLC control system for an extra-long stroke pumping unit. Background Art

[0002] In industrial production automation, programmable logic controllers (PLCs) have been increasingly widely used. It uses a class of programmable memories to store internal programs, execute user-oriented instructions such as logical operations and sequential control, and control various types of machinery or production processes through digital or analog input / output, and realizes data interaction through an RS485 communication interface. Its characteristics are simple structure, reasonable design, strong practicability, high reliability, low failure rate, strong scalability, flexible network communication, low implementation cost, and easy to promote and use.

[0003] The existing pumping unit control system is completed by an RTU (remote terminal unit) module. The program control and logical operations are not flexible enough, and the dynamometer card data is completed by a touch screen with low accuracy. In addition, in order to adapt to different well conditions, it is necessary to adjust the stroke of the pumping unit. For traditional beam pumping units, the adjustment operation of the stroke is achieved by adjusting the position of the crank pin (loosening the fixing bolts of the pin, moving the pin from the original hole position to another preset hole position, and then fixing it again) or replacing the crank (replacing the crank with a different arc), which cannot achieve automatic adjustment and is inconvenient to apply. Summary of the Utility Model

[0004] The technical solution of the utility model aims at the technical problem that the existing technical solution is too single, and provides a solution significantly different from the prior art. It mainly provides a PLC control system for an extra-long stroke pumping unit to solve the technical problems of low accuracy of the existing pumping unit control system and inability to automatically adjust the stroke of the pumping unit mentioned in the above background art.

[0005] The technical solution adopted by the utility model to solve the above technical problems is as follows:

[0006] A PLC control system for an extra-long stroke pumping unit includes a touch screen, a PLC controller, an RTU module, an electrical parameter module, and a pumping unit drive mechanism. The PLC controller includes two RS485 communication interfaces and one Ethernet communication interface. One of the RS485 communication interfaces is connected to the pumping unit drive mechanism and the electrical parameter module, and the other RS485 communication interface is connected to the RTU module. The Ethernet communication interface is connected to the touch screen.

[0007] Furthermore, the pumping unit driving mechanism includes a frequency converter, a resolver, and a permanent magnet variable frequency synchronous motor. The frequency converter is connected to the RS485 communication interface of the PLC controller. The resolver is connected to the input end of the frequency converter. The permanent magnet variable frequency synchronous motor is connected to the output end of the frequency converter.

[0008] Furthermore, a limit switch is further included, and the limit switch is connected to the input end of the PLC controller.

[0009] Furthermore, a load sensor is further included, and the load sensor is connected to the input end of the PLC controller.

[0010] Furthermore, the PLC controller, the RTU module, and the electrical parameter module are all arranged inside the control cabinet, and the touch screen is arranged outside the control cabinet.

[0011] As an optimization of the above solution, a stroke adjustment mechanism installed between the walking beam and the pumping unit driving mechanism is further included, and the stroke adjustment mechanism is connected to the output end of the PLC controller.

[0012] Furthermore, the stroke adjustment mechanism includes a first electric telescopic member installed at the active end of the walking beam and a second electric telescopic member replacing the connecting rod. The first electric telescopic member is connected to the tail bearing seat and is used to drive the tail bearing seat to move along the length direction of the walking beam. The second electric telescopic member is used to adapt to the position change of the tail bearing seat during movement.

[0013] Furthermore, a sliding limit strip extending along the length direction is provided at the active end of the walking beam, and the tail bearing seat is slidably connected to the sliding limit strip.

[0014] Furthermore, both the first electric telescopic member and the second electric telescopic member include a piston rod and a medium storage cavity, and a connecting pipe is communicated between the medium storage cavities of the first electric telescopic member and the second electric telescopic member.

[0015] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0016] (1) The present utility model provides a PLC control system for an ultra-long stroke pumping unit, including a touch screen, a PLC controller, an RTU module, an electrical parameter module, and a pumping unit driving mechanism. The PLC controller completes the operation of real-time dynamograms and historical dynamograms. The system has a simple structure, reasonable design, strong practicability, high reliability, strong scalability, flexible network communication, low implementation cost, and is convenient for popularization and use. By automatically controlling the ultra-long stroke pumping unit through this control system, the overall stability of the system can be increased, the flexibility and safety of the system can be improved, and the failure rate can be reduced.

[0017] (2) In the optimized solution of the present utility model, a stroke adjustment mechanism controlled by a PLC controller is also provided. During application, according to the well conditions, it can be manipulated through corresponding adjustment buttons, or when the need for stroke adjustment is automatically detected through the monitoring of the pumping unit status by the PLC control system, the PLC controller automatically controls the stroke adjustment mechanism to perform stroke adjustment. Compared with the prior art, it reduces the workload of manual participation, can achieve automatic adjustment, and is relatively convenient to apply.

[0018] The following will combine the drawings with specific embodiments to explain the present utility model in detail. Description of the Drawings

[0019] Figure 1 It is a block diagram of the present utility model in the first embodiment;

[0020] Figure 2 It is a structural schematic diagram of the present utility model in the second embodiment.

[0021] Reference Signs: 1, touch screen; 2, PLC controller; 3, limit switch; 4, load sensor; 5, RTU module; 6, electrical parameter module; 7, frequency converter; 8, resolver; 9, permanent magnet variable frequency synchronous motor; 10, walking beam; 11, tail bearing seat; 12, sliding limit bar; 13, first electric telescopic member; 14, connecting pipe; 15, second electric telescopic member; 16, control cabinet. Detailed Embodiment

[0022] To facilitate the understanding of the present utility model, the present utility model will be described more comprehensively below with reference to the relevant drawings. Several embodiments of the present utility model are given in the drawings, but the present utility model can be implemented in different forms and is not limited to the embodiments described in the text. On the contrary, providing these embodiments is to make the disclosed content of the present utility model more thorough and comprehensive.

[0023] Embodiment 1: Please refer with emphasis to the attached Figure 1 , a PLC control system for an ultra-long stroke pumping unit, including a touch screen 1, a PLC controller 2, a limit switch 3, a load sensor 4, an RTU module 5, an electrical parameter module 6, a frequency converter 7, a resolver 8, and a permanent magnet variable frequency synchronous motor 9.

[0024] The touch screen 1 is used for human-machine interaction;

[0025] The input end of the PLC controller 2 is connected to the limit switch 3 and the load sensor 4. The PLC controller 2 includes two RS485 communication interfaces and one Ethernet communication interface. One of the RS485 communication interfaces is connected to the frequency converter 7 and the electrical parameter module 6, and the other RS485 communication interface is connected to the RTU module 5. One Ethernet communication interface is connected to the touch screen 1. The PLC controller 2 performs the operation of real-time and historical dynamograms.

[0026] The input end of the frequency converter 7 is also connected to a resolver 8, and the output end of the frequency converter 7 is connected to a permanent magnet variable frequency synchronous motor 9.

[0027] The limit switch 3 is installed beside the sucker rod and is used to detect the end movement position of the pumping unit. When the equipment runs beyond the set safety range, the limit switch 3 will immediately send a signal to trigger the PLC control system to execute corresponding safety measures, such as stopping the equipment operation, so as to prevent equipment damage or safety accidents.

[0028] The load sensor 4 is installed on the suspension hanger and is used to monitor the load change of the pumping unit during the working process in real time, providing key data support for the PLC system.

[0029] The RTU module 5 is used to communicate with various sensors, actuators, the PLC controller 2, the central control room, etc., to ensure the smooth transmission of data and realize the remote monitoring and remote control of the operation status of the pumping unit.

[0030] The electrical parameter module 6 is mainly used for the monitoring and control of the power system. It can collect, measure and analyze electrical parameters such as voltage, current, power, power factor, electric energy, etc. in the power grid in real time.

[0031] The frequency converter 7 is used to adjust the speed of the motor according to the production situation of the oil well, and then adjust the stroke frequency of the pumping unit to meet the production requirements of different oil wells.

[0032] The resolver 8 is used to monitor and feedback the rotation position and speed information of the permanent magnet variable frequency synchronous motor 9.

[0033] The permanent magnet variable frequency synchronous motor 9 is used to drive the pumping unit to work.

[0034] The PLC controller 2, the RTU module 5, the electrical parameter module 6, the frequency converter 7 and the resolver 8 are all arranged in the control cabinet 16, and the touch screen 1 is arranged outside the control cabinet 16.

[0035] Indicator diagram calculation method: Collect the indicator diagram in the automatic operation mode of the pumping unit. According to the fixed collection interval, collect the load value, position value, current value, and power value; after starting from the origin, clear the point count cnt = 0; for each collected point, cnt++; no indicator diagram data is collected during the hovering process; until it stops at the origin again, update the number of collected points, indicator diagram ID, indicator diagram / power diagram / current diagram data; reserve 500 points for each item of data.

[0036] The specific operation of the system of the present utility model is as follows:

[0037] Manual operation: The operator sets the manual upward frequency and manual downward frequency on the touch screen 1; the operator presses and holds the upward button, and at this time the pumping unit runs upward at the set frequency and ensures the correct running direction; the operator presses and holds the downward button, and at this time the pumping unit runs downward at the set frequency and ensures the correct running direction.

[0038] First run: First step, the operator presses and holds the downward button until the bottom of the stroke, and then moves upward about 20 cm (viewed by the operator) as the origin. The origin position calibrates the PLC controller 2 to write 1 to the corresponding address of the frequency converter 7 to forcibly clear the pulse count value, and this is recorded as the origin at this time. Second step, set the parameters of the drum diameter, reduction ratio, and resolver single-turn pulse number, and set the stroke value according to the current well conditions; press and hold the upward running button and run upward to the top (about 20 cm from the upper limit, viewed by the operator), and check whether the actual position is consistent with the set stroke value. If not, readjust the parameters of the drum diameter, reduction ratio, and resolver single-turn pulse number until the real-time position is close to the stroke value (within 0.5 cm). Third step, configure the operation parameters, including the maximum current threshold, etc.; if necessary, also configure the load calibration coefficient, upper and lower limits of load protection, upper and lower limits of load range; if the setting value is unknown during the first operation, an automatic operation can be performed to obtain the upper or lower data limit value as a reference value.

[0039] Automatic operation: First step, the operator needs to complete the first-use settings through manual operation.

[0040] Second step, the operator sets the automatic operation upward frequency, downward frequency, upward deceleration operation frequency, downward deceleration operation frequency, deceleration position, and upper limit tolerance:

[0041] The upward frequency is the frequency for the upward operation of the automatic operation (the PLC controller 2 writes to the frequency converter 7 after the end of the downward operation and before the start of the upward operation); the downward frequency is the same.

[0042] Upward deceleration operation frequency. If the upward distance reaches the upward deceleration position, the PLC controller 2 writes the "upward detection operation frequency" to the frequency converter 7 and operates at low speed; for the upward deceleration operation frequency, the PLC controller 2 determines that it cannot exceed the upward operation frequency; the same applies to the downward deceleration operation frequency.

[0043] Deceleration position. Before the upward or downward operation reaches the end point, the speed needs to be reduced to avoid exceeding the range during operation.

[0044] Upper and lower limit position tolerances. When there are problems with the operation parameters adjustment and there is overshoot when running to the upper and lower end points, it does not alarm immediately, and a tolerance of 1 - 2 cm is given.

[0045] Third step, after all parameters are configured, the operator sets it to the automatic operation mode, and the PLC controller 2 operates automatically according to the configured parameters; the operator clicks the start button, and the system operates automatically according to the set parameters; click the stop button to stop the automatic operation; relevant operations are performed according to the protection configuration during the operation process.

[0046] Protection function: During the operation process, the PLC controller 2 monitors the load, current, position, resolver 8, and frequency converter 7 in real time. When a fault occurs, it performs a protection shutdown operation to ensure the normal and stable operation of the system.

[0047] Embodiment 2: The difference between this embodiment and Embodiment 1 is as follows:

[0048] It further includes a stroke adjustment mechanism installed between the walking beam 10 and the pumping unit drive mechanism, and the stroke adjustment mechanism is connected to the output end of the PLC controller 2.

[0049] Please refer to the appendix Figure 2 , the stroke adjustment mechanism includes a first electric telescopic member 13 installed at the active end of the walking beam 10 and a second electric telescopic member 15 that replaces the connecting rod (a component originally in the traditional walking beam pumping unit). The first electric telescopic member 13 is connected to the tail bearing seat 11 and is used to drive the tail bearing seat 11 to move along the length direction of the walking beam 10; the second electric telescopic member 15 is used to adapt to the position change of the tail bearing seat 11 during movement. A sliding limit strip 12 extending along the length direction is provided at the active end of the walking beam 10, and the tail bearing seat 11 is slidably connected to the sliding limit strip 12.

[0050] Both the first electric telescopic member 13 and the second electric telescopic member 15 adopt hydraulic cylinders, including piston rods and medium storage chambers, and a connecting pipe 14 is connected between the medium storage chambers of the first electric telescopic member 13 and the second electric telescopic member 15.

[0051] During application, if it is necessary to adjust the stroke of the pumping unit, the PLC controller 2 drives the first electric telescopic member 13 and the second electric telescopic member 15. The first electric telescopic member 13 drives the tail bearing seat 11 to move along the length direction of the walking beam 10. When the first electric telescopic member 13 extends, it sucks the hydraulic oil from the second electric telescopic member 15 through the connecting pipe 14, causing the second electric telescopic member 15 to shorten; when the first electric telescopic member 13 shortens, it injects the hydraulic oil into the second electric telescopic member 15 through the connecting pipe 14, causing the second electric telescopic member 15 to extend. The movement of the tail bearing seat 11 changes the position of the acting end of the crank and connecting rod member on the walking beam 10, thereby changing the deflection angle of the walking beam 10 during operation, and further realizing the adjustment of the stroke of the pumping unit.

[0052] Others are the same as in the first embodiment.

[0053] As described above, it is only the preferred embodiment of the present invention, and it does not impose any form of limitation on the present invention. Any person skilled in the art can make many possible changes and modifications to the technical solution of the present invention by using the methods and technical contents explained above, or modify it into an equivalent embodiment with equivalent changes, without departing from the scope of the technical solution of the present invention. Therefore, all equivalent changes made according to the shape, structure and principle of the present invention without departing from the content of the technical solution of the present invention shall be covered within the protection scope of the present invention.

Claims

1. An ultra-long stroke pumping unit PLC control system, characterized in that: It includes a touch screen (1), a PLC controller (2), an RTU module (5), an electrical parameter module (6), and a pumping unit drive mechanism. The PLC controller (2) includes two RS485 communication interfaces and one Ethernet communication interface. One of the RS485 communication interfaces is connected to the pumping unit drive mechanism and the electrical parameter module (6), another RS485 communication interface is connected to the RTU module (5), and the Ethernet communication interface is connected to the touch screen (1); The pumping unit drive mechanism includes a frequency converter (7), a resolver (8), and a permanent magnet variable frequency synchronous motor (9). The frequency converter (7) is connected to the RS485 communication interface of the PLC controller (2). The resolver (8) is connected to the input end of the frequency converter (7), and the permanent magnet variable frequency synchronous motor (9) is connected to the output end of the frequency converter (7); It further includes a stroke adjustment mechanism installed between the walking beam (10) and the pumping unit drive mechanism. The stroke adjustment mechanism is connected to the output end of the PLC controller (2); The stroke adjustment mechanism includes a first electric telescopic member (13) installed at the active end of the walking beam (10) and a second electric telescopic member (15) replacing the connecting rod. The first electric telescopic member (13) is connected to the tail bearing seat (11) and is used to drive the tail bearing seat (11) to move along the length direction of the walking beam (10). The second electric telescopic member (15) is adapted to the position change of the tail bearing seat (11) during movement; 2. The PLC control system of an ultra-long stroke pumping unit according to claim 1, wherein: It further includes a limit switch (3), and the limit switch (3) is connected to the input end of the PLC controller (2); 3. The PLC control system of an ultra-long stroke pumping unit according to claim 1, characterized in that: It further includes a load sensor (4), and the load sensor (4) is connected to the input end of the PLC controller (2); 4. The PLC control system of an ultra-long stroke pumping unit according to claim 1, characterized in that: The PLC controller (2), the RTU module (5), and the electrical parameter module (6) are all arranged in the control cabinet (16), and the touch screen (1) is arranged outside the control cabinet (16); 5. The PLC control system of an ultra-long stroke pumping unit according to claim 1, characterized in that: A sliding limit strip (12) extending along the length direction is provided at the active end of the walking beam (10), and the tail bearing seat (11) is slidably connected to the sliding limit strip (12); 6. The PLC control system of an ultra-long stroke pumping unit according to claim 1, characterized in that: Both the first electric telescopic member (13) and the second electric telescopic member (15) include a piston rod and a medium storage cavity, and a connecting pipe (14) is connected between the medium storage cavities of the first electric telescopic member (13) and the second electric telescopic member (15);

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