Pressure transmitter how to correctly select - Huaqiang Electronic Network

How to Buy Pressure Transmitters

When purchasing pressure transmitters, users often consider multiple factors. Choosing the right instrument can help avoid many issues during later use. Today, I’ll walk you through the correct way to select a pressure transmitter.

1. What kind of pressure do you need to measure?

First, determine the maximum pressure in your system. It’s generally recommended to choose a transmitter with a range about 1.5 times higher than the maximum value. This is because many systems—especially those involving water pressure—can experience pressure spikes and irregular fluctuations. These can damage the sensor over time. A sustained high pressure or even a slight exceedance of the transmitter's calibrated maximum can reduce its lifespan and accuracy. You might add a buffer to manage these fluctuations, but that could slow down the response time. So, when selecting a transmitter, make sure to consider its pressure range, accuracy, and stability.

2. What type of medium are you measuring?

Viscous liquids or mud may block the pressure interface, while solvents or corrosive substances could damage the materials in direct contact with the media. This will influence whether you need a transmitter with a direct barrier or special materials for the media contact area.

3. What level of accuracy is required?

Consider factors like accuracy, nonlinearity, hysteresis, repeatability, temperature effects, zero offset, and scale drift. The main considerations are nonlinearity, hysteresis, and repeatability. The higher the accuracy, the more expensive the device tends to be.

4. What is the operating temperature range?

Most transmitters are calibrated for two temperature ranges: one for normal operation and another for temperature compensation. The normal operating range refers to the conditions under which the transmitter won’t be damaged. If the temperature exceeds the compensation range, performance might not meet specifications. The temperature compensation range is usually smaller than the operating range, ensuring consistent performance within it. Temperature changes affect output in two ways: zero drift and full-scale drift. For example, a change of X%/°C in full scale or reading can impact accuracy. Understanding these effects is crucial for proper transmitter use.

5. What output signal do you need?

Options include mV, V, mA, frequency, or digital outputs. The choice depends on factors such as distance between the transmitter and the controller, presence of noise or interference, and whether an amplifier is needed. For short distances, mA output is often the most cost-effective. If amplification is necessary, a built-in amplifier is ideal. For long-distance transmission or environments with strong electrical interference, mA or frequency outputs are better choices. In high RFI or EMI environments, additional protection or filters may also be required.

6. What excitation voltage is required?

The output signal type determines the excitation voltage selection. Many transmitters have internal voltage regulation, allowing a wide supply voltage range. Others require a stable power source. When choosing a transmitter, consider both the operating voltage and system cost.

7. Is interchangeability important?

Check if the transmitter can work across different systems. This is especially relevant for OEM applications. Once delivered, recalibrating the device can be costly. An interchangeable transmitter allows for easy replacement without affecting the overall system performance.

8. Does the transmitter maintain stability after prolonged use?

Many transmitters experience “drift” after extended use. It’s important to assess the stability before purchase to minimize future maintenance and downtime.

9. What is the transmitter’s housing like?

The housing is often overlooked, but it plays a key role in long-term performance. Consider the working environment—humidity, installation method, and potential vibration or impact. A robust housing ensures reliable operation in harsh conditions.

In conclusion, choosing the right pressure transmitter can significantly improve performance and reduce errors. A poor selection can lead to frequent malfunctions, reduced lifespan, and even complete failure, resulting in operational disruptions and financial loss.