A structure of scalable and configurable interface for sensor and actuator devices in smart farming system

Agriculture is the most significant industry directly related to human survival. However, the reduction of the labor force according to the continuous decreasing population and aging population brings a decrease in productivity. A smart farm networking system can be an alternative solution to solve these problems. Due to lack of interoperability and scalability, however, many smart farm systems are not sufficiently suitable to be utilized in a real field and a market. This paper proposes a structure of scalable and configurable I/O module interface for the smart farm control system. The proposed smart farm interface makes easy to extend sensor-actuator interface modules which are used for interfacing between sensor-actuator and the main controller, from which the scalability and interoperability can be gained. Also, Sensor data (Digital, Analog) can be easily obtained and the actuator data (PWM, Direction, On/Off) can be controlled regardless of its interface. The interface module can be easily added on the main controller, so additional functionalities to be able to support various sensor and actuator can be easily merged. These advantages are obtained by using local Modbus protocol between the sensor-actuator interface modules and the main controller. The sensor-actuator interface module is designed to divide into two parts; one is the communication parts with the main controller, and the other is the control part for sensors and actuators. With this structure, acquiring data from sensor data and/or sending control data to the actuator can be done independently with the main controller. An operation of sensors and actuators which are connected to the sensor-actuator interface module can be asynchronously done by using shared local registers. From the proposed structure, it is possible to provide configurable interfaces with the scalability using the modular sensor-actuator interface structure under the various environments that are needed to control the smart farm system.