You set the RAA100 rudder number or instance using Maretron's DSM200 or DSM250 display in the following way. Enter menu mode, scroll to "Configuration…" and press enter. Scroll to "Device Configuration…" and press enter. Scroll to the row containing the RAA100 and press enter. Scroll to "Rudder Number:" and press enter. Scroll until you find the appropriate rudder number and press enter.