Positioner Response Time Measurement Using Preliminary Stroke
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Solution Overview
Problem
The conventional process for finding the average response time TRES in positioners is extremely time-consuming due to the need for multiple full stroke operation cycles, which occupies a significant portion of the time required for automatic setup.
Innovation Solution
A positioner with an electropneumatic converting portion that stores valve opening positions and elapsed times to calculate the first response time during a single full stroke operation, allowing the average response time TRES to be determined using two full stroke operation cycles, thereby reducing the overall setup time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple full stroke operation cycles are performed to measure response times in both directions, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The patent applies preliminary action by performing a first full stroke operation cycle before automatic setup to pre-measure the response time in one direction. This pre-measured response time is stored and reused during the actual automatic setup process, eliminating the need to perform another full stroke operation cycle solely for measurement purposes. The preprocessing of measurement data reduces the overall setup time while maintaining measurement precision.
Solution Approach 2:
The patent merges the measurement function with the setup process by utilizing the first full stroke operation cycle for both positioning purposes and response time measurement. Instead of separating measurement and setup into distinct phases requiring multiple cycles, the system combines these functions, allowing response time data to be captured during the necessary positioning operations, thereby reducing total cycles required.
2Reliability
If full stroke operation cycles are performed three times to measure response times, then reliability of control parameter determination is improved, but productivity decreases
Solution Approach 1:
The system performs a preliminary full stroke operation cycle to measure and store response time data before the actual automatic setup begins. This preliminary measurement ensures reliable control parameter determination without requiring three separate cycles during the setup process itself, thereby improving productivity while maintaining reliability.
Solution Approach 2:
The system uses the first full stroke operation cycle to serve dual purposes: achieving the necessary valve positioning and simultaneously collecting response time measurement data. This self-service approach eliminates the need for dedicated measurement cycles, allowing the setup process to proceed more efficiently without compromising the reliability of control parameter determination.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly shortens the time required to find the average response time TRES, thereby reducing the time needed for the automatic setup process.
Implementation Method 1
an electropneumatic converting portion for converting an inputted electric signal into an air pressure
Data Source
AI summary
In a positioner, a driving signal IM is set to IMMIN (the minimum), a valve opening position A after the valve has then settled is stored, the driving signal IM is set to IMMAX (the maximum), a valve opening position B after the valve has then settled is stored, and the valve opening positions up until the opening of the valve arrives at the valve opening position B from the valve opening position A are stored together with the elapsed times as time series position information J1, where, based on this stored time series position information J1, the time for the opening of the valve to traverse between two prescribed valve opening positions that are established in the interval between the valve opening position A and the valve opening position B is calculated as a first response time Tup.