Modeling the Raven SCS-700 chemical injection system with carrier control with sprayer simulation

Mathematical models of the chemical and carrier control sub-system of the R aven SCS-700 chemical injection system were developed. The step responses o f both control sub-systems were predictable using the models. From this pro cess of model development, it was observed that the voltage saturation effe ct limited the response speed of the carrier valve motor and the resulting speed at which changes could be made to the carrier flow rate. The rate at which flow rate measurements were available limited the extent to which val ve motor speed could be increased without causing instability. The performa nce of three different types of sprayers was simulated using these models. Simulations were performed with and without carrier control. Sprayers using carrier control misapplied to smaller areas than those without carrier con trol. Differences between the response of the chemical and carrier sub-syst em controllers produced concentration variations that contributed to applic ation error These errors, however were small relative to the errors caused by response rimes of both systems and the ground speed sampling rate.