Device for monitoring a control unit
AssigneesThyssen Aufzuge GmbH, Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
InventorsKarl-Otto Schollkopf, Werner Bohm, Gerhard Kellings, Michael Bollerott, Klaus Scherer
Life of this patent
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Abstract
The invention relates to a monitoring device for a control unit having a ety chain. In accordance with the invention, the monitoring device has a testable switching device which is provided with input and output terminals such that a monitoring loop may be set up from a plurality of testable switching devices and a sequence of digital signals can, in particular, be transmitted via this loop as a continuous signal so that a "digital stand-by current loop" is obtained.
Claims20
Apparatus for monitoring an electrical control system in which a plurality of electronic switching units are coupled to form a safety chain, said switching units each having a non-contacting, testable sensor and control electronics associated therewith for detecting and altering the state of said sensor, comprising:
- an ascending branch leading from a primary control to communicate signals from said primary control to successive ones of said switching units coupled along said ascending branch;
- a return branch leading from the last one of said switching units coupled to said ascending branch back to said primary control via said successive switching units, said ascending and return branches being coupled together at said last one of said switching units to form a monitoring loop;
- and
- an electronic changeover device associated with each of said successive switching units for interrupting said return branch when the sensor associated with that switching unit is not in a state fulfilling a safety criterion for said safety chain.
An electronic switching unit for use in an electrical control system in which a plurality of such units are coupled to form a safety chain, said switching unit comprising:
- a non-contacting, testable sensor;
- control electronics for detecting and altering the state of said sensor;
- an ascending branch terminal for coupling said unit to an ascending branch that communicates signals from a primary control of said electrical control system to a succession of said units;
- a return branch terminal for coupling said unit to a return branch leading back to said primary control via said succession of units;
- and
- an electronic changeover device for interrupting said return branch when said sensor is not in a state fulfilling a safety criterion for said safety chain.
Dependencies are inferred from the claim text.