How does a multimeter measure the pressure sensor

The use of a multimeter to test the quality of the pressure sensor can mainly be carried out through the following steps:

1. Preparation before testing

1. Turn off all power supplies and remove the connectors on the pressure sensor ports.

2. Check the instructions of relevant instruments in detail to ensure correct operation and avoid operation errors.

Ii. Operation

### 1. Bridge detection

** * Purpose ** : The main detection sensor circuit is correct, generally Wheatstone full bridge circuit.
** * Method ** :
+ Use the ohm file of the multimeter.
+ Measure the impedance between inputs and the impedance between outputs.
+ These two impedances are the input and output impedances of the pressure sensor.
** * Judgment ** :
+ If the impedance is infinite, the bridge is disconnected, indicating that there is a problem with the sensor or the pin is not correctly defined.

### 2. Zero point detection
** * Purpose ** : To detect the zero point output of the sensor under the condition of no applied pressure.
** * Method ** :
+ Use the voltage level of the multimeter.
+ Detect zero output of the no-pressure sensor.
** * Judgment ** :
+ This output is usually mV voltage.
+ If it exceeds the technical indicators of the sensor, it means that the zero deviation of the sensor is out of range.

### 3. Pressure detection
** * Purpose ** : To detect the output change of the sensor under pressurized conditions.
** * Method ** :
+ Power the sensor.
+ Blow the pilot hole of the pressure sensor with your mouth.
+ Use the voltage profile of the multimeter to detect voltage changes at the sensor output.
** * Judgment ** :
+ If the relative sensitivity of the pressure sensor is large, the voltage change will be obvious.
+ If there is no change at all, it is necessary to switch to the pressure source.

### 4. Output signal test (optional)
** * Purpose ** : To detect whether the output signal of the sensor meets the specifications.
** * Method ** :
+ Use a signal generator to send a signal of a specific frequency to the sensor.
+ Use an oscilloscope to connect to the signal output line of the sensor and observe the output signal curve.
+ Use a multimeter to measure the output signal voltage.
** * Judgment ** :
+ Compare the measurement results with the requirements in the specification book, if it meets the requirements, the sensor output signal test is qualified.

### 5. Precautions
* If accurate testing is required, a standard pressure source is used and the sensor is calibrated according to the amount of pressure and the amount of change in the output signal.
* Carry out temperature detection of relevant parameters when conditions permit.

Through the above steps, you can initially judge the quality of the pressure sensor, but it is recommended to use professional testing equipment for detection, for more systematic and accurate testing.