Siemens Aktiengesellschaft

Gerhard Rumold

Helmut Schummer

Heinrich Winkler

Dieter Munz

Herbert Heitzer

Georg Russ

Klaus Schmiedel

An input stage for programmable controllers in which a Schmitt trigger and a two-terminal configuration having a negative resistance characteristic are combined in an integrated circuit. A first resistor supplementing this bipolar configuration to form a constant-current sink is connected externally of the integrated circuit in parallel with the bipolar configuration. A power loss mainly develops in the first resistor which is external of the integrated circuit so that multi-channel input stages are able to be realized cost-effectively without requiring a supply of cooling air to cool the integrated circuit. A second resistor may be connected external of the integrated circuit in series with the two-terminal configuration to further reduce power loss within the integrated circuit and to limit the current flowing into the integrated circuit.

Apparatus for maintaining a low power loss within an input stage for

An output circuit with a controller and intelligent output stages for process control where the output stages are supplied with power from separate voltage sources which are electrically separated from each other. The actuating commands from the controller for semiconductor switches in the output stages and feedback signals to the controller from the output stages are carried back and forth via optical couplers. Each output stage receives its own direct current supply, which is obtained by rectifying a chopper current supply. The feedback signals are transmitted serially being clocked by pulses derived from the chopper current supply. Thus, actuating commands may be issued without retrospective effect. Switching operations may be carried out during the process. Diagnostic signals concerning the load current circuit can provide feedback efficiently.

Feedback-free output circuit configuration

A method and device for data transmission over several parallel lines, in particular over optical fibers is described for transmitting measured values from a measuring station arranged at a high-voltage line to an evaluating electronic system at a high data rate, a high utilization of the available transmission lines, preferably optical fibers, is desirable. To this end, via a clock line, clock messages are relayed which are separated from each other by a synchronization interval (P2) and which begin at least with a fixed clock message portion (PT), which may preferably be followed by a freely usable clock message portion. The receiver recognizes each message start by the synchronization interval of the clock messages and forms during the fixed clock message portion synchronous sampling pulses, which may be followed by asynchronous sampling pulses for the duration of the free clock message portion. The transmitter can now send via data lines data messages which begin synchronously with the fixed clock message portions and need not contain any fixed programmed pulses for the recognition of telegram messages.

Method and device for data transmission over several parallel lines, in

A detector for detecting breakdowns on the high-voltage side of an electric precipitator, the voltage of which is supplied from an a-c network through a thyristor control circuit, a high-voltage transformer and a rectifier. The improvement of the invention comprises means for continuously comparing characteristic parameters of successive half-waves of variations of the voltage at the precipitator. A predetermined deviation of the characteristic parameters comprises a criterion for determining a breakdown of the precipitator voltage.

Detector for detecting voltage breakdowns on the high-voltage side of an

A measuring circuit for measuring the ground resistance of an ungrounded power circuit, particularly a d-c system supplied from a converter circuit in which a series circuit including an a-c voltage generator, a measuring resistor and a coupling member is connected between the object of the measurement and ground and an evaluation circuit including a phase sensitive rectifier circuit forms the unknown ground resistance by dividing the active component of the current driven by the generator voltage through the series circuit into the voltage between the measurement object and ground.

Growing community of inventors

Bubenreuth, Germany

Gerhard Rumold