Please use this identifier to cite or link to this item: http://dspace.ups.edu.ec/handle/123456789/1043
Title: Diseño e implementación de un prototipo para control automático de nivel y caudal de líquidos para los laboratorios de ingeniería mecánica UPS-Quito
Authors: Machado Ramírez, César Orlando
Molina Coronado, Robinson Paúl
Advisor: Vergara Cedeño, Joseph Ramón
Keywords: MECÁNICA
DISEÑO DE SOFTWARE
CONTROL AUTOMÁTICO
LÍQUIDOS
CONTROL HIDRÁULICO
Issue Date: Jul-2011
Abstract: El presente trabajo tiene como finalidad dotar a los laboratorios de mecánica de un sistema mediante el cual los estudiantes podrán realizar prácticas físicas de automatización y control industrial, como son la medición, control y monitoreo de variables de proceso en este caso nivel y caudal. Para cumplir con el objetivo planteado, se diseñó y construyó un prototipo automatizado con posibilidad de controlar dos variables caudal y nivel, dicho prototipo cuenta con un sistema de tubería por el cual circula agua impulsada por una bomba. Dicha bomba está regulada en su velocidad por un variador de frecuencia. Tanto para el control de caudal así como para el control de nivel, el agua circula desde el tanque de reserva hacia el tanque de prueba, y de éste hacia el tanque de reserva nuevamente formando de esta manera un circuito cerrado de agua. Para la medición de caudal se utilizó un sensor tipo turbina marca KOBOLD con un rango de medición de 2 a 40 [lts/min] con una exactitud de medición de 1.5%, además se consideró que es de un costo bajo. El incremento o decremento del flujo (caudal) se lo realizó variando la velocidad de la bomba mediante el variador de velocidad SINAMICS G110. Mientras que para la medición de nivel se ha utilizado un sensor de presión hidrostática que tiene un rango de medición de 0 a 10 [Kpa] con una exactitud en la medición del 0.5%, el cual censará la columna de agua y de acuerdo a la presión nos dará la altura de la misma de forma directa. Para hacer posible la variación del nivel en el tanque de medición se utilizó en conjunto una válvula manual tipo compuerta y una electroválvula al final del mismo. Para el control del prototipo se utilizó el PLC S7-200 (Controlador Lógico Programable), con un CPU 224 DC/DC/DC, con una señal de 4 a 20 [mA], para el cual se diseñaron algoritmos de control con rutinas PID. El manejo del prototipo es de forma remota, para lograr esto se implementó un HMI realizado el software Intouch 10, con ventanas que permiten interactuar de xix acuerdo a las necesidades planteadas al momento de abrir la ventana de control principal. Para el manejo total del prototipo y su comunicación, con la finalidad de realizar una adquisición de datos en cada una de las pruebas realizadas se utilizó en conjunto un grupo de programas como son: Intouch 10, STEP 7 MicroWIN SP7 4, KEPServer EX5 y S7-200 PC Access V1.02. En las pruebas de funcionamiento realizadas se determinaron parámetros óptimos (Ganancia = 7.5, Tiempo de Integración = 0.21 min, Tiempo de Derivación = 0 y tiempo de muestreo = 0.1 seg.), para el control de nivel, con los cuales arrojaron resultados satisfactorios, haciendo notar que la calibración del controlador fue apropiada, al variar cada uno de estos valores se notó que el sistema tiende a variar en rapidez de respuesta y estabilidad. Para el tramo de 0 a 100 mm se obtuvo un tiempo de reacción de 1minuto con 25 segundos para estabilizarlo totalmente, el error en el setpoint de nivel fue de 0.5 mm. Para un segundo tramo tomado de 390 a 500 mm se obtuvo un tiempo de reacción de 1 minuto para una estabilización satisfactoria y el error máximo en el setpoint de nivel fue de 2.6 mm. Para el control de caudal el PID tiene los siguientes valores (Ganancia = 0.8, Tiempo de Integración = 0.02, Tiempo de Derivación = 0 y tiempo de muestreo = 0.1 segundos), se tomó muy en cuenta que el sensor de turbina no arroja valores exactos cuando el caudal es menor a 0.5 [GPM], es decir cuando son menores al 5%, esto de acuerdo a los valores de diseño del transmisor de caudal KOBOLD DRS. Para el tramo de 0 a 15 litros sobre minuto se obtuvo un tiempo de estabilización de 40 segundos, mientras que el error de caudal se reduce en la práctica a la exactitud del transmisor que es 1.5 %. Además de realizó un tercer PID utilizando el transmisor de caudal para realizar dosificaciones tomando en cuenta el volumen del líquido con los siguientes valores (Ganancia = 0.8, Tiempo de Integración = 0.02, Tiempo de Derivación = 0 y tiempo de muestreo = 0.1 segundos). Para un valor de 4 litros se obtuvo un tiempo de reacción de 16 segundos, mientras que el error fue de 0.032 litros.
Description: In this document it is shown the design and performance of laboratories equip with a system through which students can perform physical practices of industrial automation and control, such as measurement, control and monitoring of process variables. To meet the goal set, it was designed and built an automated prototype with the ability to control flow and level, the prototype has a system of pipes through which water flows driven by a pump. The pump speed is regulated by an inverter. In both, flow control and level control, water flows from the reservoir into the test tank, and then into the reservoir again thus forming a closed water circuit. For flow measurement it was used a KOBOLD turbine sensor with a measuring range from 2 to 40 [l / min], a measurement accuracy of 1.5%. The increase or decrease of the flow was made by varying the speed of the pump through the SINAMICS G110 drive speed. As for the level measurement it is used a hydrostatic pressure sensor that has a measuring range from 0 to 10 [kPa] with a measurement accuracy of 0.5%, which still counted the water column and according to the pressure will transmit the height of it directly. For the control of the prototype it was used the S7-200 (Programmable Logic Controller) with a CPU 224 DC / DC / DC, a signal 4 to 20 [mA], for which control algorithms were designed with PID routines. The handling of the prototype was implemented in Intouch HMI software, with windows that let you interact according to the needs. For the overall management of the prototype and its communication, in order to perform data acquisition in each of the tests, are used together as a group of programs: Intouch 10, STEP 7 MicroWIN SP7 4, EX5 and S7 KEPServer -200 V1.02 PC Access. In performance tests were determined optimal parameters (gain = 7.5, integration time = 0.21 min, derivative time = 0 and sampling time = 0.1 sec.) The control level yielded satisfactory results before the calibration of the controller was completed. For the range from 0 to 100 mm it was obtained a reaction time of 1 minute 25 seconds to fully stabilize, the error in the setpoint level was 0.5 mm. For a second segment taken from 390 to 500 mm it was obtained a reaction time of 1 minute for a successful stabilization and the maximum error in the setpoint level was 2.6 mm. The PID flow control has the following settings (gain = 0.8, Integration Time = 0.02, Derivation time = 0 and sampling time = 0.1 seconds). For the range from 0 to 15 liters per minute it yielded a stabilization time of 40 seconds, while the accuracy of the transmitter is 1.5%. In addition it was programmed a third PID to dosage volume of water by counting the volume that pass through the flow meter. The following settings were obtained (gain = 0.8, Integration Time = 0.02, Derivation time = 0 and sampling time = 0.1 seconds). For a volume of 4 liters it was obtained a reaction time of 16 seconds, while the error was 0.032 liters. In this document it is shown the design and performance of laboratories equip with a system through which students can perform physical practices of industrial automation and control, such as measurement, control and monitoring of process variables. To meet the goal set, it was designed and built an automated prototype with the ability to control flow and level, the prototype has a system of pipes through which water flows driven by a pump. The pump speed is regulated by an inverter. In both, flow control and level control, water flows from the reservoir into the test tank, and then into the reservoir again thus forming a closed water circuit. For flow measurement it was used a KOBOLD turbine sensor with a measuring range from 2 to 40 [l / min], a measurement accuracy of 1.5%. The increase or decrease of the flow was made by varying the speed of the pump through the SINAMICS G110 drive speed. As for the level measurement it is used a hydrostatic pressure sensor that has a measuring range from 0 to 10 [kPa] with a measurement accuracy of 0.5%, which still counted the water column and according to the pressure will transmit the height of it directly. For the control of the prototype it was used the S7-200 (Programmable Logic Controller) with a CPU 224 DC / DC / DC, a signal 4 to 20 [mA], for which control algorithms were designed with PID routines. The handling of the prototype was implemented in Intouch HMI software, with windows that let you interact according to the needs. For the overall management of the prototype and its communication, in order to perform data acquisition in each of the tests, are used together as a group of programs: Intouch 10, STEP 7 MicroWIN SP7 4, EX5 and S7 KEPServer -200 V1.02 PC Access. In performance tests were determined optimal parameters (gain = 7.5, integration time = 0.21 min, derivative time = 0 and sampling time = 0.1 sec.) The control level yielded satisfactory results before the calibration of the controller was completed. For the range from 0 to 100 mm it was obtained a reaction time of 1 minute 25 seconds to fully stabilize, the error in the setpoint level was 0.5 mm. For a second segment taken from 390 to 500 mm it was obtained a reaction time of 1 minute for a successful stabilization and the maximum error in the setpoint level was 2.6 mm. The PID flow control has the following settings (gain = 0.8, Integration Time = 0.02, Derivation time = 0 and sampling time = 0.1 seconds). For the range from 0 to 15 liters per minute it yielded a stabilization time of 40 seconds, while the accuracy of the transmitter is 1.5%. In addition it was programmed a third PID to dosage volume of water by counting the volume that pass through the flow meter. The following settings were obtained (gain = 0.8, Integration Time = 0.02, Derivation time = 0 and sampling time = 0.1 seconds). For a volume of 4 liters it was obtained a reaction time of 16 seconds, while the error was 0.032 liters.
URI: http://dspace.ups.edu.ec/handle/123456789/1043
Appears in Collections:Ingeniería Mecánica KENNEDY - Tesis de Pregrado

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