Pipeline liquid pressure controller and control method thereof

Abstract

The invention discloses a pipeline liquid pressure controller and a control method thereof. The controller comprises a single-chip microcomputer (SCM), a dual output switching power supply, a power supply switch, an ADC analog-digital conversion module, an RS485 communication interface, a working mode selection switch, a pressure setting selection switch, a pressure adjustment switch, a start-stop switch, an operation indicator light and a display module. The SCM is connected with a frequency converter through the RS485 communication interface. The frequency converter is connected with a variable frequency motor. The variable frequency motor controls the rotational speed of a medicine pump. A water outlet of the medicine pump is connected with a pressure sensor and a liquor pipeline separately. The pressure sensor is used to detect the pressure of the liquor in the liquor pipeline. An input end of the dual output switching power supply is connected with a single-phase power supply, and an output end of the dual output switching power supply is connected with the power supply switch. The power supply switch is connected with the pressure sensor and the SCM separately. The pressure sensor is connected with the SCM through the ADC analog-digital conversion module. According to the invention, the RS485 communication interface is used to control the work of the frequency converter, the communication distance is farther, the anti-interference ability is stronger, and the controller works more reliably.

Description

technical field [0001] The invention relates to a pipeline constant pressure controller, in particular to a pipeline liquid pressure controller and a control method thereof, which belong to the design field of plant protection medicine and equipment controllers. Background technique [0002] In fruit tree planting and production management, pesticide spraying and water and fertilizer irrigation operations account for a large proportion of orchard management operations. In the current orchard management, different agricultural machinery and equipment are generally used for pesticide spraying and water and fertilizer irrigation, which increases the cost of equipment. [0003] Most of the existing spraying systems are non-frequency conversion spraying systems, which are generally in a full-power operation state. As the operator shifts the working point, the number of spray guns will be different, so it is easy to cause unstable spray pressure and even burst of chemical liquid p...

AI Technical Summary

Problems solved by technology

The Chinese invention patent with the authorized announcement number CN 101690923 B discloses a pipeline constant pressure spray control device based on a single-chip microcomputer. The device converts the pressure signal detected by the pressure transmitter into a digital quantity through a conditioning circuit. After the set pressure value is compared, the pressure error and the change rate of the pressure error are obtained, and the control value is obtained according to the control algorithm. The control value is converted into an analog voltage by another conditioning circuit, and sent to the analog control terminal of the frequency converter to control the frequency converter. Output the frequency of alternating current to change the speed of the variable frequency motor. The invention patent uses analog signals to control the frequency converter, which is easily affected by the electromagnetic interference of the motor and lightning weather, resulting in a short system life. At the same time, there is only one working mode of constant pressure spraying. The system Low reuse rate

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