EP0175656A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
System for the two-way line transmission of electrical signals and an indicator instrument incorporating such a system
Assignee: Istrumenti Di Misura Cgs SpA
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Filing: 1985-09-09
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Granted: —
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Expires: 2005-09-09
Abstract
Abstract @ A monitoring unit supplied with a signal to be measured which can control the operation of actuator elements such as electro-mechanical relays, is connected through a single transmission line to a visual display unit for the presentation of the signal to be measured in visual form. The visual display unit has associated regulating elements which allow threshold values of the signal to be selected (for example minimum and maximum values) in correspondence with which it is wished to vary the operating conditions of the said relays. Indicator lights associated with an indicator module indicate the operating conditions of these actuator elements. The monitoring unit includes a power source which causes an electrical current flow in the transmission line, the average magnitude of which represents the value of the signal being measured. The visual display unit on the other hand includes a current meter which is sensitive to the current flowing in the transmission line and comparator elements, the switching threshold of which is at a level which can be selected by means of regulating members. When the signal being measured reaches one of these treshold levels, a voltage generator in the visual display unit applies a corresponding voltage to the transmission line. This voltage is detected by a voltage meter present in the monitoring unit. The voltage meter acts on a corresponding relay causing it to change its state. Furthermore, an auxiliary oscillator associated with the voltage meter passes a pulse signal into the transmission line through the current generator with an average value of zero, this pulsed signal being receveid by the visual display unit and activating the corresponding indicator light. The remote supply of the visual display unit is provided for by an alternating current signal with an average value of zero fed through the transmission line.
Inventors
- 👤 Renzo Fedrigo
- 👤 Franco Fere
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 04:00
CPC Classifications
H; H04; H04L; H04L5/00; H04L5/14; H04L5/1423; G; G08; G08C; G08C19/00; G08C19/02; G08C19/025
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
184 words
System for the two-way transmission of electrical signals between a first (2) and a second (3) unit connected by a single transmission line (4) which can operate simultaneously to transmit and receive signals, characterised in that: - the first unit (2) includes a current generator (11, llb) which can cause an electrical current to flow in the transmission line (4) the magnitude of which is indicative of the signals (20, 22, 23) sent from the first unit (2) to the second unit (3); the first unit (2) further including a voltage meter (24) sensitive to the voltage (V' 4 , V" 4 , V"' 4 ), present in the transmission line (4), and - the second unit (3) includes a voltage generator (33) which can apply an electrical voltage to the transmission line (4) the value of which is indicative of the signals (V' 4 , V" 4 , V"' 4 ), sent from the second unit (3) to the first unit (1); the second unit (3) further including a current meter which is sensitive to the current flowing in the transmission line (4).
Claim 2
Dependent Claim
184 words
System for the two-way transmission of electrical signals between a first (2) and a second (3) unit connected by a single transmission line (4) which can operate simultaneously to transmit and receive signals, characterised in that: - the first unit (2) includes a current generator (11, llb) which can cause an electrical current to flow in the transmission line (4) the magnitude of which is indicative of the signals (20, 22, 23) sent from the first unit (2) to the second unit (3); the first unit (2) further including a voltage meter (24) sensitive to the voltage (V' 4 , V" 4 , V"' 4 ), present in the transmission line (4), and - the second unit (3) includes a voltage generator (33) which can apply an electrical voltage to the transmission line (4) the value of which is indicative of the signals (V' 4 , V" 4 , V"' 4 ), sent from the second unit (3) to the first unit (1); the second unit (3) further including a current meter which is sensitive to the current flowing in the transmission line (4).
Claim 3
Dependent Claim
76 words
System according to Claim 1, characterised in that one of the units (2) includes a generator (11, 18) which produces an alternating signal (21) with an average value of zero intended to be sent to the other unit (3) and in that the other unit (3) includes a transformer and rectifier circuit (26, 27) which can derive a substantially D.C. signal from the alternating signal (20) which can be used to supply the other unit (3).
Claim 4
Dependent Claim
366 words
Indicator instrument including: - a monitoring unit (2) which, in use, is supplied with a signal to be measured (measurement signal) and which is able to control selectively the operation of at least one actuator element (A I and A 2 ) and - a visual display unit (3) for presenting the measurement signal in a visual form, provided with regulating means (8, 9) for selecting at least one threshold level for the measurement signal at which it is desired to change the operating condition of the at least one actuator element (A 1 . A 2 ) characterised in that: - the monitoring unit (2) and the visual display unit (3) are connected together through a transmission line (4) - the monitoring unit (2) includes a current generator (11, lib) which in use is supplied with the measurement signal and causes an electrical current to flow in the transmission line (4) with at least one spectral component (20) the magnitude of which is indicative of the values of the measurement signal; the monitoring unit (2) further including a voltage meter (24, 25) which, in use, can detect the value of the voltage present on the transmission line (4) and can control selectively, in the presence of a predetermined variation (V' 4 , V" 4 , V"' 4 ) in the said voltage value in the transmission line (4), a corresponding variation in the operating condition of the at least one actuator element (A 1 , A 2 ) and - the visual display unit (3) includes a current meter (42) which is sensitive to the at least one spectral component (20) of the current flowing in the transmission line (4); the visual display unit (3) further including threshold comparator elements (38, 39) sensitive to the magnitude of the at least one spectral component and the threshold switching levels of which arc selectively determinable by regulating means (8, 9) and at least one voltage generator (33) which is controlled by the threshold comparator elements (38, 39) and causes variations ( V ' 4' V" 4 , V"' 4 ) in the voltage present in the transmission line (4) upon switching of the comparator elements (38, 39).
Claim 5
Dependent Claim
366 words
Indicator instrument including: - a monitoring unit (2) which, in use, is supplied with a signal to be measured (measurement signal) and which is able to control selectively the operation of at least one actuator element (A I and A 2 ) and - a visual display unit (3) for presenting the measurement signal in a visual form, provided with regulating means (8, 9) for selecting at least one threshold level for the measurement signal at which it is desired to change the operating condition of the at least one actuator element (A 1 . A 2 ) characterised in that: - the monitoring unit (2) and the visual display unit (3) are connected together through a transmission line (4) - the monitoring unit (2) includes a current generator (11, lib) which in use is supplied with the measurement signal and causes an electrical current to flow in the transmission line (4) with at least one spectral component (20) the magnitude of which is indicative of the values of the measurement signal; the monitoring unit (2) further including a voltage meter (24, 25) which, in use, can detect the value of the voltage present on the transmission line (4) and can control selectively, in the presence of a predetermined variation (V' 4 , V" 4 , V"' 4 ) in the said voltage value in the transmission line (4), a corresponding variation in the operating condition of the at least one actuator element (A 1 , A 2 ) and - the visual display unit (3) includes a current meter (42) which is sensitive to the at least one spectral component (20) of the current flowing in the transmission line (4); the visual display unit (3) further including threshold comparator elements (38, 39) sensitive to the magnitude of the at least one spectral component and the threshold switching levels of which arc selectively determinable by regulating means (8, 9) and at least one voltage generator (33) which is controlled by the threshold comparator elements (38, 39) and causes variations ( V ' 4' V" 4 , V"' 4 ) in the voltage present in the transmission line (4) upon switching of the comparator elements (38, 39).
Claim 6
Dependent Claim
185 words
Indicator instrument according to Claim 3, characterised in that: - the monitoring unit includes a supply oscillator (18) which can generate an alternating signal with a zero average value the frequency spectrum of which occupies a substantially discontinuous frequency band of the range of frequencies occupied by the frequency spectrum of the said at least one spectral component (20) corresponding to the measurement signal: the alternating signal with zero average value being supplied to the current generator (11, llb) superposed on the measurement signal, whereby the current flowing in the transmission line (4) includes at least two distinct spectral components (20, 21) corresponding respectively to the measurement signal and to the said alternating signal produced by the supply generator (18), and - the visual display unit (3) includes a transformer and rectifying circuit (26, 27) which is associated with the current meter (42) and can extract from the current flowing in the transmission line (4) the spectral component (21) corresponding to the said alternating signal and which can generate therefrom a substantially D.C. electrical signal usable for the supply of the visual display unit (3).
Claim 7
Dependent Claim
194 words
Indicator instrument according to Claim 3, characterised in that: - the monitoring unit (2) includes an auxiliary oscillator (19) which is connected to the voltage meter (24, 25) and can generate, when the voltage meter (24, 25) controls predetermined variations in the operating conditions of the at least one actuator element (A 1 , A 2 ), corresponding pulsed signals with a zero average value, each of which is indicative of a corresponding operating condition of the at least one actuator element (A l , A 2 ); the pulsed signals with zero average value being supplied to the current generator (11, 16) superposed on the measurement signal, whereby the current flowing in the transmission line (4) includes pulsed components (22, 23) correspnding to the respective signals generated by the auxiliary oscillator (18) and - the visual display unit (3) includes a separator circuit carrying associated warning elements (10a, 10b) which is sensitive to the pulsed components (22, 23) of th current flowing in the transmission line (4) and in the presence of a predetermined pulsed component (22, 23) of the said current, can cause the activation of a corresponding warning element (10a, 10b).
Claim 8
Dependent Claim
120 words
Indicator instrument according to Claim 5, characterised in that the auxiliary oscillator (19) generates pairs of pulsed signals with a zero average value, each pair including two substantially identical signals in antiphase with each other, intended to be generated in selective alternation with each other to cause the presence of corresponding pulsed current components in the transmission line (4) and in that the display unit (3) includes, for each pair of pulsed antiphase signals , a differentiator element (43) sensitive to the pulsed components of the current flowing in the transmission line (4) and which, in dependence on the phase of the pulsed component (22, 23) present in the transmission line (4), can activate a respective warning element (10a, 10b).
Claim 9
Dependent Claim
136 words
Indicator instrument according to any one of Claims 3 to 6, characterised in that: ' - the voltage generator of the visual display unit (3) includes an operational amplifier (33), the output of which in use is coupled so as to transmit voltage to the transmission line (4) and defines a flow path for the at least one spectral component (20) the strength of which is indicative of the values of the measurement signal; the outputs of the threshold comparator elements (38, 39) being connected, in a generally sum configuration, to the non-inverting input of the operational amplifier (33), whereby the operational amplifier (33) can apply differentiated voltage levels (V' 4' V" 4 , V"' 4 ) to the transmission line (4), these constituting linear combinations of the signals output by the comparator elements (38, 39).
Claim 10
Dependent Claim
50 words
Indicator instrument according to any one of Claims 3 to 7, characterised in that the voltage meter of the monitoring unit (2) includes a threshold comparator circuit (25) which can discriminate between the different voltage levels (V' 4' V" 4 , V"' 4 ) present on the transmission line (4).
Claim 11
Dependent Claim
12 words
The whole substantially as described and illustrated and for the purposes specified.
Claim 12
Dependent Claim
12 words
The whole substantially as described and illustrated and for the purposes specified.
References Cited (Backward Citations)
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