Designed to mount directly to top of control valve, Research Control® SRD991 uses linear connection, which mitigates hysteresis between positioner and actuator by feeding back actual position of actuator consistently and accurately. Unit is available with graphical LCD screen, 2 levels of diagnostics, and variety of protocols including HART, PROFIBUS-PA, and FOUNDATION Fieldbus H1. All diagnostic features can be configured and displayed by positioner DTM.