How to test the performance of MEMS pressure transmitters?

Hey there! As a supplier of MEMS pressure transmitters, I've had my fair share of experiences in testing these nifty devices. MEMS pressure transmitters are everywhere these days - from automotive systems to industrial machinery, and even in medical equipment. Their performance can make or break the systems they're integrated into, so it's super important to test them properly. In this blog, I'm gonna walk you through how to test the performance of MEMS pressure transmitters.

Understanding the Basics

Before we jump into the testing process, let's quickly go over what MEMS pressure transmitters are. MEMS stands for Micro-Electro-Mechanical Systems. These pressure transmitters use tiny mechanical structures on a semiconductor chip to measure pressure. They're known for their small size, low cost, and high performance.

Initial Checks

When you first get your hands on a MEMS pressure transmitter, there are a few initial checks you should do. First, take a good look at the physical condition of the device. Check for any visible damage like cracks, scratches, or bent pins. A damaged transmitter might not work properly, so it's important to catch these issues early on.

Next, make sure the electrical connections are correct. The transmitter usually has a power supply, a ground, and an output signal. Double - check that the wiring is done right and that there are no loose connections. You don't want a simple wiring problem to mess up your test results.

Pressure Calibration

One of the most important aspects of testing a MEMS pressure transmitter is pressure calibration. This involves comparing the output of the transmitter to a known pressure source. You'll need a pressure calibration device, which can be a dead - weight tester or a pressure calibrator.

1. Set up the calibration equipment: Connect the MEMS pressure transmitter to the calibration device. Make sure the connections are tight and secure. You might need some adapters depending on the type of ports on the transmitter and the calibration device.
2. Apply known pressures: Start by applying a low pressure, like atmospheric pressure. Record the output of the transmitter. Then, gradually increase the pressure in small increments and record the corresponding output at each step. Do this up to the maximum rated pressure of the transmitter.
3. Analyze the results: Plot the output of the transmitter against the applied pressure. You should get a linear relationship. If there are significant deviations from the expected linear curve, it could indicate a problem with the transmitter. For example, if the output is lower than expected at high pressures, the transmitter might be experiencing over - range damage.

Accuracy Testing

Accuracy is a key performance metric for MEMS pressure transmitters. To test the accuracy, you need to compare the measured values from the transmitter to the actual values.

1. Use a reference standard: You can use a high - accuracy pressure sensor as a reference standard. Connect both the reference sensor and the MEMS pressure transmitter to the same pressure source.
2. Measure and compare: Apply different pressures and record the readings from both sensors. Calculate the difference between the readings of the MEMS pressure transmitter and the reference sensor. This difference is the error. The accuracy of the transmitter is usually expressed as a percentage of the full - scale output. For example, if the full - scale output is 100 psi and the maximum error is 1 psi, the accuracy is 1%.

Response Time Testing

The response time of a MEMS pressure transmitter is how quickly it can respond to a change in pressure. To test the response time, you'll need a fast - acting pressure source.

1. Generate a step change in pressure: You can use a solenoid valve to quickly change the pressure applied to the transmitter. Connect the transmitter to a data acquisition system to record the output.
2. Measure the response: When the pressure changes, record the time it takes for the transmitter's output to reach a certain percentage (usually 90%) of its final value. This is the response time. A fast response time is important in applications where the pressure changes rapidly, like in automotive engine control systems.

Hysteresis Testing

Hysteresis is the difference in the output of the transmitter when the pressure is increasing compared to when it's decreasing. To test for hysteresis:

1. Apply increasing and decreasing pressures: Start by applying a low pressure and gradually increase it to the maximum rated pressure. Record the output at each step. Then, gradually decrease the pressure back to the starting point and record the output again.
2. Calculate the hysteresis: Compare the output values at the same pressure points during the increasing and decreasing pressure cycles. The difference between these values is the hysteresis. A good MEMS pressure transmitter should have low hysteresis, which means it gives consistent readings regardless of whether the pressure is increasing or decreasing.

Temperature Testing

Temperature can have a significant impact on the performance of MEMS pressure transmitters. To test the temperature performance:

1. Use a temperature chamber: Place the transmitter inside a temperature chamber and set the temperature to different values. You can test at low temperatures (e.g., - 40°C), room temperature (e.g., 25°C), and high temperatures (e.g., 85°C).
2. Measure the output at different temperatures: Apply a constant pressure and record the output of the transmitter at each temperature. Calculate the change in output due to temperature. This is called the temperature coefficient. A low temperature coefficient indicates that the transmitter is less affected by temperature changes.

Long - Term Stability Testing

Long - term stability is important for applications where the transmitter needs to provide accurate readings over a long period of time. To test long - term stability:

1. Monitor the output over time: Place the transmitter in a stable environment and apply a constant pressure. Continuously monitor the output for a long period, like several months.
2. Analyze the data: Look for any trends or drifts in the output over time. A stable transmitter should have minimal changes in output over the long term.

MEMS Pressure Sensor for Shield Tunneling Machine

If you're in the shield tunneling machine industry, you might be interested in our MEMS Pressure Sensor for Shield Tunneling Machine. These sensors are specifically designed to withstand the harsh conditions in shield tunneling applications, including high pressures and vibrations.

Conclusion

Testing the performance of MEMS pressure transmitters is a comprehensive process that involves multiple steps. By testing for pressure calibration, accuracy, response time, hysteresis, temperature performance, and long - term stability, you can ensure that the transmitters meet the required standards.

If you're in the market for high - quality MEMS pressure transmitters or need help with testing and calibration, feel free to reach out for a procurement discussion. We're here to provide you with the best solutions for your pressure measurement needs.

References

• "MEMS Pressure Sensors: Technology and Applications" by X. Bao and N. Lu
• "Handbook of Pressure Measurement" by P. A. Peacock