Chemical Injector Motor Current Measurement Error Handling
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Solution Overview
Problem
The detection of injection pressure using motor current measurement in chemical liquid injectors can lead to erroneous detection at startup due to inrush current, and incorrect graph displays when the motor stops, causing confusion about the actual injection pressure.
Innovation Solution
A chemical liquid injector with a motor current measuring circuit and an injector control circuit that temporarily stops the motor when the calculated injection pressure reaches a preset limit, displaying the limit pressure instead of zero during motor stoppage, to accurately represent the injection pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If motor current measurement is used to detect injection pressure, then the number of parts is reduced, but erroneous detection occurs at startup due to inrush current
Solution Approach 1:
The control circuit identifies the startup phase and temporarily suspends pressure detection during this period, preventing erroneous detection due to inrush current before it can trigger false alarms
Solution Approach 2:
The system dynamically adjusts the pressure detection function based on motor operation state, enabling detection during normal operation while disabling it during startup when inrush current occurs
2Reliability
If the motor operation is stopped when injection pressure reaches the upper limit, then safety is improved, but the display shows zero pressure causing user confusion
Solution Approach 1:
The display shows the upper limit pressure value as an intermediary representation during motor stoppage, maintaining information continuity and preventing user confusion while the motor is temporarily stopped for safety
Solution Approach 2:
The system provides continuous feedback to the user about the injection pressure state even during motor stoppage by displaying the upper limit value, ensuring the user understands the pressure condition that triggered the stop
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 solution ensures accurate display of injection pressure close to the actual pressure even when the motor is stopped, preventing misinterpretation of low pressure as a motor stop due to high pressure limits.
Implementation Method 1
a motor current measuring circuit configured to measure motor current, the motor current being a current flowing through the motor
Data Source
Figure 1
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AI summary
Problems arising when the result of motor current measurement is used to calculate the injection pressure of a chemical liquid are solved. A chemical liquid injector includes piston driving mechanism 161 driven by motor 162, motor current measuring circuit 163 measuring the motor current, touch panel 103, and injector control circuit (152, 158) calculating the injection pressure of the chemical liquid by using the result of measurement by motor current measuring circuit 163 and displaying the calculated injection pressure on touch panel 103. The injector control circuit temporarily stops the operation of motor 162 when the injection pressure reaches a preset limit pressure during the chemical liquid injection, and displays the limit pressure as the injection pressure on touch panel 103 instead of the calculated injection pressure during the stop of the operation of motor 162 due to the injection pressure reaching the limit pressure.