A system for a turbine comprising: a turbine-generator system, control components for controlling and monitoring the turbine-generator system, a turbine-generator controller controlling the turbine-generator system, the turbine-generator controller being coupled to the turbine-generator system and the control components and being configured to execute a first plurality of functions comprising a shutdown function and a startup function for the turbine-generator system using a plurality of inputs from the turbine-generator system and the control components; a safety instrumented system controller coupled to the turbine generator controller, the safety instrumented system controller being functionally independent from the turbine-generator controller, characterized in that the SIS controller is coupled to the turbine-generator system and the control components, the SIS controller being configured to receive inputs from the turbine-generator system and the control components, and to execute a second plurality of functions (108, 110) using a plurality of inputs from the turbine-generator system and the control components, wherein the second plurality of functions comprises at least a startup permitting function carried out in response to a start command received by the SIS controller that permits the turbine-generator controller to start up the turbine-generator system, and a shutdown causing function that causes the turbine-generator controller to shut down the turbine-generator system, where the SIS controller permits a startup function of the turbine-generator controller based on a plurality of inputs from turbine-generator system and the control components. a turbine-generator system, control components for controlling and monitoring the turbine-generator system, a turbine-generator controller controlling the turbine-generator system, the turbine-generator controller being coupled to the turbine-generator system and the control components and being configured to execute a first plurality of functions comprising a shutdown function and a startup function for the turbine-generator system using a plurality of inputs from the turbine-generator system and the control components; a safety instrumented system controller coupled to the turbine generator controller, the safety instrumented system controller being functionally independent from the turbine-generator controller, the SIS controller is coupled to the turbine-generator system and the control components, the SIS controller being configured to receive inputs from the turbine-generator system and the control components, and to execute a second plurality of functions (108, 110) using a plurality of inputs from the turbine-generator system and the control components, wherein the second plurality of functions comprises at least a startup permitting function carried out in response to a start command received by the SIS controller that permits the turbine-generator controller to start up the turbine-generator system, and a shutdown causing function that causes the turbine-generator controller to shut down the turbine-generator system, where the SIS controller permits a startup function of the turbine-generator controller based on a plurality of inputs from turbine-generator system and the control components.