Calibrating Pressure Transducer Calibration Logs across Automated Production Lines
Reconciling pressure transducer calibration logs requires time-stamped multi-point span verification to eliminate silent thermal drift and zero-null errors.
Hysteresis Curve
Meaning
Graphical representations of the lag between an input stimulus and the resulting output show how a system retains a memory of its previous state. The hysteresis curve is common in magnetic materials and mechanical sensors where the path of the return stroke differs from the initial movement. This property causes a discrepancy in readings depending on whether the value is rising or falling.
Input Lag
Delay in the response of a sensor occurs as the internal components overcome friction or magnetic resistance. On a hysteresis curve, this is visible as a horizontal shift where the output stays at a lower value than expected during the ramp up phase. Minimizing this lag is a primary goal for precision instrument manufacturers.
Magnetic Remanence
Materials that stay magnetized after the external field is removed demonstrate the memory effect of the system. The hysteresis curve tracks how much energy is required to return the material to a neutral state. High remanence is desirable for permanent magnets but problematic for electrical transformers.
Response Shift
Difference between the ascending and descending data points defines the width of the error band. An instrument with a wide hysteresis curve requires a more complex calibration table to provide accurate measurements across the entire range. Software corrections use the direction of travel to select the correct value from the data.