Abstract: A position control circuit having a demodulator with automatic tuning capability for use in an electro-hydraulic positioning system used to position a servo device. The position control circuit includes the demodulator, an analog to digital converter with an input voltage range, and a microcontroller. The demodulator has a gain and is operable to convert a feedback signal from the servo device to a position signal having a lower voltage value when the servo device is at its 0% position and an upper voltage value when the servo device is at its 100% position; the lower voltage value and upper voltage values being a function of the demodulator gain.

Abstract: A once-through steam generator comprises an economizer, an evaporator and a superheater connected in series one below the other in a boiler pass, and are acted upon by a hot gas mass flow flowing in the opposite direction. In order to prevent thermal shock during the introduction of cold feed water when starting the steam generator from a hot state, i.e., with an economizer, evaporator and superheater which are empty and heated to the exhaust gas temperature, a high-temperature starter is connected upstream of the economizer and is arranged above the latter in the boiler pass. The starter acts as a heat buffer so that the economizer, evaporator and superheater are first acted upon by superheated steam and are continuously cooled to their normal operating temperature. The starter is constructed in such a way that its portion which first comes into contact with the cold feed water does not support the steam pressure so that it need only absorb thermal stresses.