Response time evaluation of real-time sensor based variable rate technology equipment

Real-time sensor based variable rate technology (VRT) equipment is complex with many different components working together to achieve a desired output. The equipment provides rate-controller set-point every second creating more challenges in terms of functioning of each component and its response time to achieve a variable rate application with existing rate-controllers, valves and nozzles. All components involved operate on inputs from the other thereby inducing a time delay. This time delay among components questions the credibility on performance of sensor based commercially available VRT equipment and its overall response time. Response time of commercially available real-time sensor based VRT system was evaluated with two applicator configurations: Applicator equipped with Capstan PWM technology with fixed orifice nozzles and an applicator equipped with Raven FC-Valve with variable orifice nozzles. Parameters pressure, flow rate, controller input from the sensor system were measured and logged using a data acquisition system. The data were analyzed to determine if the applied rate correctly follows the desired set-point rates or if there is any delay in overall response time of VRT equipment for different settings of the rate-controller. Results showed that rate-controller settings were different for both applicator configurations for achieving minimum response time of around 0.5 s. This work will aid in determining the spatial resolution for variable rate application using commercially VRT equipment.