Current Interface Converter Circuit for On-Board Self-Testing
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Solution Overview
Problem
Conventional measuring device electronics require manual intervention and external test equipment for checking the current interface, leading to interruptions in normal measuring operations and increased technical effort, as well as the need for regular calibration of expensive equipment.
Innovation Solution
A converter circuit with a microprocessor that allows for on-board testing of the current interface, enabling automatic monitoring and adjustment of the current characteristic curve function without manual intervention or external equipment, using stored control and current value sequences to detect deviations and recalibrate as necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual checking of current interface with external test equipment is used, then measurement accuracy can be verified, but normal measuring operations are interrupted and technical effort increases
Solution Approach 1:
The converter circuit performs self-testing by using its own microprocessor and internal resources to check the current interface characteristic curve function. The microprocessor outputs test control values, reads back actual current values via the current signal output, and compares them against expected values stored in memory, enabling the system to verify its own accuracy without external equipment or manual intervention.
Solution Approach 2:
The microprocessor serves multiple functions: it controls the current interface during normal operation, generates test control values for self-checking, reads current values from the current signal output, and stores reference data in memory. This multi-functionality eliminates the need for separate external test equipment while maintaining measurement verification capabilities.
2Reliability
If manual checking of current interface is performed, then deviations can be detected, but device complexity and calibration requirements increase
Solution Approach 1:
The self-testing mechanism implements feedback by reading the actual current values from the current signal output and comparing them against the expected test values stored in memory. When deviations are detected, the system can trigger alerts or initiate corrective actions, ensuring reliable operation while maintaining a relatively simple device architecture through automated monitoring.
3Measurement precision
If external test equipment is used for checking, then current interface can be monitored, but cost and technical effort increase
Solution Approach 1:
The system uses its own microprocessor, memory, and current signal output to perform monitoring functions that would otherwise require external test equipment. This self-service approach eliminates the need for expensive external calibration devices while maintaining the ability to detect and respond to deviations in the current interface characteristic curve function.
Data Source
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AI summary
The converter circuit serves to convert a digital measurement signal (xD) representing the temporal profile of a time-varying physical and/or chemical quantity (x) into an analog measurement signal dependent on the same digital measurement signal, with a signal current (ix) of which a current intensity represents a measurement value (X) for the quantity. For this purpose, the converter circuit comprises a current interface with a control input (Ictrl_in), a current signal output (11, I2), and a current output (ID_out). Furthermore, the converter circuit includes a microprocessor with a measurement signal input (xD_in) for the digital measurement signal (xo), a current signal input (ID_in) connected to the current signal output (IIST-out) of the current interface, and a control output (Ictrl_out) connected to the control input (Ictrl_in) of the current interface.The current interface is configured to allow the signal current to flow through the current output and, during this process, to regulate the current to a steady-state current level (Ix) corresponding to a control value (WD,j) currently applied at the control input (Ictrl_in), and to output a current value sequence (iD) at the current signal output (IIST_out). Furthermore, the microprocessor is configured to generate a measurement sequence based on the digital measurement signal (xD), and based on this, to generate a control value sequence (wD) and output it at the control output. The current interface is also used to monitor and/or verify the current interface based on the control value sequence (wD) and the current value sequence (io).