EP0131474A2
Expired / Lapsed
EP
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Control system
Assignee: Herga Electric Ltd
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Filing: 1984-07-12
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Granted: —
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Expires: 2004-07-12
Abstract
Abstract A fail-safe control system comprises sensing means (10) for detecting a predetermined condition, means (12, 14) for monitoring the output from the sensing means, and control means (16) operable by the monitoring means to generate a control signal when the predetermined condition occurs. The control system includes two circuit arrangements (12, 28, 32 and 14,30,34), which independently cause the control signal to be generated when the predetermined condition occurs, whereby a failure in one such circuit arrangement does not affect generation of the control signal caused by the other such circuit arrangement. The control system also includes resetting means (36) for resetting parts of the control system following generation of the control signal, which resetting means are operable only when both circuit arrangements have responded to the output from the sensing means to independently cause the control signal to be generated.
Inventors
- 👤 Peter Martin Tracey
- 👤 Gordon Oscroft
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 04:02
CPC Classifications
G; G01; G01R; G01R19/00; G01R19/165; G01R19/16566; G01R19/1659
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
100 words
A fail-safe control system comprising sensing means (10) for detecting a predetermined condition, means (12,14) for monitoring the output from the sensing means, and control means (16) operable by the monitoring means to generate a control signal when the predetermined condition occurs, characterised in that the sensing means comprise optical fibre sensing means (20,22,24), and two circuit arrangements (12,28,32 and 14,30,34) are provided, which independently cause the control signal to be generated when the predetermined condition occurs, whereby a failure in one such circuit arrangement does not affect generation of the control signal caused by the other such circuit arrangement.
Claim 2
Dependent Claim
100 words
A fail-safe control system comprising sensing means (10) for detecting a predetermined condition, means (12,14) for monitoring the output from the sensing means, and control means (16) operable by the monitoring means to generate a control signal when the predetermined condition occurs, characterised in that the sensing means comprise optical fibre sensing means (20,22,24), and two circuit arrangements (12,28,32 and 14,30,34) are provided, which independently cause the control signal to be generated when the predetermined condition occurs, whereby a failure in one such circuit arrangement does not affect generation of the control signal caused by the other such circuit arrangement.
Claim 3
Dependent Claim
26 words
A control system according to claim 1 characterised in that the sensing means comprise a sensor having a common output coupled to the two circuit arrangements.
Claim 4
Dependent Claim
36 words
A control system according to claim 2 characterised in that the sensor is operable to supply a constant output when the predetermined condition is absent and to supply a changed output when the predetermined condition occurs.
Claim 5
Dependent Claim
39 words
A control system according to claim 2 characterised in that the sensor is operable to supply a cyclically variable output when the pre- determined condition is absent and to supply a . modified output when the predetermined condition occurs.
Claim 6
Dependent Claim
33 words
A control system according to any preceding claim characterised in that the monitoring means comprise two monitoring circuits (12,14), each providing at least part of a respective one of the two circuit arrangements.
Claim 7
Dependent Claim
30 words
A control system according to claim 5 characterised in that each monitoring circuit comprises a comparator circuit (12,14) for comparing the output from the sensing means with a reference signal.
Claim 8
Dependent Claim
77 words
A control system according to claim 6 characterised in that each comparator circuit is arranged to compare the output from the sensing means with a lower reference value and with an upper reference value and is adapted to supply an indication signal to the control means to cause the control signal to be generated in the event that the output from the sensing means decreases below the lower reference value or increases above the upper reference value.
Claim 9
Dependent Claim
27 words
A control system according to claim 6 or 7 when dependent from claim 3 characterised in that the reference signals for the two comparator circuits are similar.
Claim 10
Dependent Claim
47 words
A control system according to claim 6 or 7 when dependent from claim 4 characterised in that the reference signals for the two comparator circuits are different and the two comparator circuits are responsive to the output from the sensing means in different portions of its cycle,
Claim 11
Dependent Claim
35 words
A control system according to any preceding claim characterised in that the control means comprise two control circuits (28,32 and 30,34), each providing at least part of a respective one of the two circuit arrangements.
Claim 12
Dependent Claim
36 words
A control system according to claim 10 characterised in that each control circuit comprises latch means (28,30) operable by the monitoring means to cause and sustain generation of the control signal when the predetermined condition occurs.
Claim 13
Dependent Claim
38 words
A control system according to claim 10 ' or 11 characterised in that each control circuit comprises a switch (32,34) and the control means further comprises control signal generating means (R,S) actuable independently by both of the switches.
Claim 14
Dependent Claim
63 words
A control system according to any preceding claim further characterised by means (36) for resetting parts of the control system after the control signal has been generated, which resetting means are enabled to reset such parts of the control system only if both of the two circuit arrangements have caused the control signal to be generated following an occurrence of the predetermined condition.
Claim 15
Dependent Claim
25 words
A control system according to claim 13 when dependent from claim 13 characterised in that the resetting means are enabled by operation of both latches.
Claim 16
Dependent Claim
82 words
A control system according to claims 13 or 14 characterised in that the resetting means comprise a manually actuable switch (40) and are arranged, when enabled, to generate a resetting pulse following operation of the manually actuable switch, and in that a trailing edge detector (42) is provided, which is arranged to detect a trailing edge of the resetting pulse and to enable the control system to generate the control signal only following detection of the trailing edge of the resetting pulse.
Claim 17
Dependent Claim
64 words
A control system according to any preceding claim further characterised by means for compensating for variation in the operating characteristics of parts of the control system, the compensating means comprising reference sensing means (60,90) for generating a reference output, and calibration means (70,100) responsive to the reference output for adjusting at least one of the sensing means, the monitoring means and the control means.
Claim 18
Dependent Claim
40 words
A control system according to claim 16 characterised in that the reference sensing means are further arranged to detect the predetermined condition, and wherein the control means are operable in response to the reference output to generate the control signal.
Claim 19
Dependent Claim
21 words
A control system according to any preceding claim characterised in that the sensing means are embodied in a safety mat (48).
Claim 20
Dependent Claim
30 words
A control system according to any of claims 1 to 17 characterised in that the sensing means are embodied in a pressure sensitive edge (110) for a moving part (112).
Claim 21
Dependent Claim
20 words
A control system according to any of claims 1 to 17 characterised in that the sensing means comprise a switch.
References Cited (Backward Citations)
No citation records indexed.
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