Explanation of common sensor performance terms
Pressure sensor performance terminology
● Thermal sensitivity drift
The change of sensitivity caused by the sensor operating temperature deviating from the calibration temperature. It is generally expressed as the relative change rate of sensitivity for each degree of change.
● Thermal hysteresis
At a certain point in the measuring range of the sensor, when the temperature approaches and reaches a certain temperature in two ways of gradually increasing and gradually decreasing, the maximum difference of the sensor output is generally expressed as a relative value.
Terminology of flow sensor performance
● Working pressure
The pressure range that the sensor can work normally under the condition of meeting various performance indicators.
● Operating temperature
The temperature range of the measured medium that the sensor can work normally.
● Working density
The density of the measured medium that the sensor can work normally under the condition of meeting the accuracy requirements.
● Working viscosity
The viscosity range of the measured medium that the sensor can work normally under the condition of meeting various performance indicators.
● Range ratio
For a certain medium, the sensor can meet the ratio of the upper measurement limit and the lower measurement limit of the performance index.
● Minimum flow
The minimum flow value that the sensor can work normally or meet the measurement accuracy requirements.
● Pressure loss
When working under specified conditions, the difference between the pressure at the inlet and the pressure at the outlet of the sensor.
● Density error
The error caused by the difference between the density of the measured medium and the density of the calibration medium when the sensor is in use.
● Medium error
The error caused by the difference between the measured medium and the measured medium during calibration when the sensor is in use.
● Pulsation error
When in use, the sensor output cannot respond to the error caused by the rapid flow change.
Terminology of temperature sensor performance
● Maximum operating temperature
Under the specified technical conditions, the maximum allowable service temperature for continuous operation of the sensor within the time of completing the measurement.
● Allowable working pressure
The maximum external pressure that the temperature sensor can withstand without damage under the specified measurement environment conditions.
● Thermal inertia
The hysteresis characteristic that the temperature indicated by the temperature sensor lags behind the actual temperature of the medium.
● Thermal potential
When the two contacts of the thermocouple are at different temperatures and under the zero current state, the electromotive force generated in the thermocouple circuit is called the thermoelectric potential or the Seebeck potential.
● Thermoelectric potential rate
The rate of change of thermoelectric electromotive force with temperature. The thermoelectric potential rate is also called the Seebeck coefficient.
● Allowable working current
The maximum working current allowed to pass through the resistance temperature sensor under the condition of not exceeding the temperature measurement error range.
● Rated power
The allowable power consumption of the thermistor under long-term continuous load under the condition of temperature of 25 ° C, relative humidity of 45%~80% and atmospheric pressure of 0.85-1.05 standard atmospheric pressure.
● Measured power
The power consumed when the resistance change caused by the heating of the measuring power supply does not exceed 0.1% under the specified ambient temperature.
● Thermistor power temperature characteristics
The relationship between the temperature of the thermistor itself and the applied stable power.
● Thermistor voltage and current characteristics (volt-ampere characteristics)
The relationship between the voltage at both ends of the thermistor and the steady-state current passing through the resistor body at the specified temperature.
● Thermistor resistance - temperature characteristics
Characterize the compliance relationship between the actual resistance value of thermistor and temperature.
● Actual resistance value
At the specified temperature, the change of resistance value caused by the application shall not exceed 0 The resistance value measured by 1% of the measured power.
● Nominal resistance value
It refers to the resistance value at 25 ° C marked on the thermistor.
● Positive temperature coefficient
The resistance temperature coefficient a is a positive value, which is called positive temperature coefficient. Its physical meaning is that the resistance value increases with a certain relationship as the temperature increases.
● Negative temperature coefficient
The resistance temperature coefficient a is a negative value, which is called negative temperature coefficient. Its physical meaning is that as the temperature rises, the resistance value decreases according to a certain relationship.
● Material constant (thermal sensitivity index)
A constant describing the resistance characteristics of a negative temperature coefficient thermistor material. Its size depends on the activation energy of the material. In the operating temperature range, it is not a strict constant, and will increase slightly with the increase of temperature.
● Dissipation constant
The ratio of the change of power dissipation of thermistor to its temperature change.
● Uniformity
The degree of homogeneity of the thermoelectric material of the thermocouple.
Terminology of displacement, angle and speed sensor performance
● Zero position output
The output value when the measured physical quantity is zero after the sensor is powered on.
● Percentage of residual voltage
The difference between the applied voltage of the sensor and the rated output voltage and the percentage of the applied voltage.
● Contact resistance
Resistance between electrical contact elements.
● Equivalent noise resistance
It is assumed that the noise voltage between electrical contact elements is generated by the contact resistance that changes instantaneously, and is equivalent to the contact resistance that generates the same noise voltage.
● Load error
Additional error caused by external load of sensor.
● Vibration error
Additional error of sensor due to vibration.
● Impact error
Additional error of sensor due to impact.
● Acceleration error
The additional error caused by the acceleration of the sensor.
● Anti-electromagnetic wave interference
The ability of the sensor to resist radio electromagnetic interference.
● Anti-magnetic interference
The ability of the sensor to resist external magnetic field interference.
● Resistance to thermal radiation
The ability of the sensor to resist thermal radiation.
● Anti-nuclear rolling
The ability of the sensor to resist nuclear radiation.
