Samson Aktiengesellschaft

Samson Ag Mess- Und Regeltechnik

Fausto Crespo Vidal

Lothar Kemmler

Heinfried Hoffmann

Thomas Karte

Karl-Bernd Schaertner

Dirk Klee

Stefan Flentge

Andreas Fiebiger

Karl-Bernd Schärtner

A method for preventing control-induced oscillations in a valve with a pneumatic actuator and position control with an integrating component, including the following steps: Checking whether oscillations of the valve member occur by counting the zero crossings or extreme values of the control difference. If oscillations were detected, it is checked whether they result from oscillations of the set point. If not, the dead zone is increased and/or the gain parameter is decreased. If no oscillations were detected, it is checked whether wear in the drive has exceeded a predetermined measure. If so, the dead zone is decreased and/or the gain parameter is increased. In this way, oscillations caused by the I-component of the control can be detected and stopped. Further changes to the parameters are only made when friction is expected to have decreased due to wear.

Preventing control-induced oscillations of the position of a valve member in a valve with pneumatic actuator

A method for determining a break-away force in an actuator is provided, the actuator comprising an actuator armature including a positioning element movable in relation to the actuator housing. The positioning element is movable by means of an actuator drive such that a driving force is applied through the actuator drive to the positioning element. The actuator is in a resting state in the beginning, the driving energy required for moving the actuator drive is successively increased, wherein the driving energy is converted into a driving force by driving means, and a measurement value at the actuator drive is measured by at least one sensor, wherein as soon as a change of the measurement value is detected, a state is verified in which a holding force counteracts the movement of the position element.

Method for determining the break-away force of an actuator

In a limit signal indicator for determining two positions of a pneumatically operated positioning device, a position sensor detects a position of the positioning device. A first signal transmission contact, a second signal transmission contact, and a microprocessor are provided. The first and the second signal transmission contacts each output a respective electrical limit position signal, the limit position signals representing an adoption of the first and the second positions or of at least one position of the positioning device above or below a predetermined set limit value. At least one of the signal transmission contacts is connected for signal transmission so that in case of a malfunctioning of a signal transmission, the switch amplifier is capable of generating an emergency signal above a maximum limit value or below a lower limit value, and to transmit the emergency signal to an external processing location. The microprocessor, upon detecting a specific operational malfunctioning, actuating the positioning device and executing an emergency procedure according to which the same emergency signal is generated and output at the second signal transmission contact.

Limit signal indicator and method for operating a limit signal indicator

A method for monitoring a the contact resistance (R) of the wiper of a sensor for a variable quantity, with a potentiometer (), in which the position of the center tap () determines the value of the quantity, is improved in such a way that, first, when the sensor is used in an automatic control circuit, no control deviations occur and, second, the contact resistance of the wiper can be monitored with precision. This is achieved by the cyclic switching-on of a load (R), so that the contact resistance (R) of the wiper can be determined on the basis of the change in the voltage divider ratio.

Method for monitoring the contact resistance of a wiper

Electropneumatic position controller having two solenoid operated pneumatic valves, each of which is respectively provided with a regulating pressure nozzle, an exhaust nozzle, a discharge line leading to a power amplifier, and a hinged armature that is driven by an electromagnetic system and alternatively closes the regulating pressure nozzle or the exhaust nozzle, characterized in that the solenoid valves each respectively comprise a channel that communicates with their exhaust nozzle and can be manually closed, the respective power amplifier being capable of being switched as a result of the closing of said channel even without electrical excitation of the magnet system.

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Langenselbold, Germany

Fausto Crespo Vidal