Two-Wire Measuring Circuit With Dynamic Regulator Voltage Drop
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Solution Overview
Problem
Measuring devices connected via a single pair of lines are susceptible to interference and have limited input impedance, leading to increased susceptibility to voltage fluctuations and reduced capacity for multiple devices on the same bus line due to low voltage drops across regulators.
Innovation Solution
The measuring device adjusts the voltage drop across the series regulator based on input voltage using a characteristic curve that increases the voltage drop above a minimum value when sufficient energy is available, enhancing immunity to interference and increasing input impedance, allowing more devices to be connected in parallel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the voltage drop across the series regulator is kept at minimum value to improve energy efficiency, then energy use is optimized, but susceptibility to interference increases and input impedance decreases
Solution Approach 1:
The voltage drop across the series regulator is made dynamically adjustable rather than fixed. The control unit modifies the voltage drop as a function of input voltage according to a characteristic curve, allowing the system to adapt between energy efficiency mode (low voltage drop) and interference immunity mode (high voltage drop) based on operating conditions
Solution Approach 2:
The voltage drop parameter across the series regulator is changed based on input voltage conditions. When input voltage is high, the voltage drop is increased to improve interference immunity; when input voltage is low, the voltage drop is reduced to maintain energy efficiency. This parameter adjustment resolves the contradiction between energy efficiency and interference susceptibility
2Reliability
If the voltage drop across the series regulator is increased to improve immunity to interference, then reliability improves, but energy consumption increases
Solution Approach 1:
The system dynamically adjusts the voltage drop across the series regulator based on real-time input voltage conditions. The control unit uses a characteristic curve to determine the optimal voltage drop that provides sufficient interference immunity while minimizing energy waste, rather than maintaining a constantly high voltage drop
Solution Approach 2:
The voltage drop parameter is modified as a function of input voltage. At high input voltages, the voltage drop is increased to improve reliability and interference immunity. At low input voltages, the voltage drop is reduced to conserve energy. This conditional parameter change resolves the contradiction between reliability and energy consumption
3Reliability
If the input impedance is increased to reduce susceptibility to voltage fluctuations, then reliability improves, but the number of devices that can be connected in parallel decreases
Solution Approach 1:
The input impedance is made dynamically adjustable through modification of the series regulator's voltage drop. The control unit increases voltage drop (and thus input impedance) when interference immunity is needed, and reduces voltage drop (and input impedance) when maximum device capacity is required, allowing flexible adaptation to system requirements
Solution Approach 2:
The input impedance parameter is changed by adjusting the voltage drop across the series regulator. When high interference immunity is needed, input impedance is increased. When maximum system capacity is needed, input impedance is reduced. This parameter adjustment resolves the contradiction between reliability and system capacity
Data Source
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AI summary
The invention relates to a measuring device for measuring a process variable, which device exhibits the least sensitivity to disturbance possible and allows flexible use, comprising an input circuit (1) having a line pair, which comprises a supply line (9) and a return line (11) and can be connected to a higher-level unit and via which, during operation, the measuring device is supplied with power and signals, in particular an output signal reflecting the process variable, are transmitted between the measuring device and the higher-level unit, and via which an input voltage (Uin) is present at the measuring device during operation, further comprising an in-phase regulator (13) inserted in the supply line (11) for setting a current flowing over the line pair, a quadrature regulator (15), which is connected downstream of the in-phase regulator (13) and is inserted in a shunt arm (17) connecting the supply line (9) to the return line (11), and a unit (19) for adjusting a voltage drop (ΔU) present over the in-phase regulator (13), which unit adjusts the voltage drop (ΔU) over the in-phase regulator (13) in accordance with the input voltage (Uin) that is present for input voltages (Uin) greater than a predetermined minimum input voltage (Uin min) to a value which is predetermined by a characteristic (ΔUsoll(Uin)) for the respective input voltage (Uin) and is above a minimum value (ΔUmin) required for the operation of the in-phase regulator (13), and a measuring sensor (3), which is connected to the input circuit (1) and supplied with power by the input circuit (1), for determining the process variable and for generating a measurement signal (M) reflecting the process variable.