Pressure sensor and transmitter common faults - Solutions - Huaqiang Electronic Network

Photocoupler

Pressure sensors and transmitters are commonly prone to several types of failures. The first issue is when the sensor fails to respond to pressure changes. In such cases, start by checking if the pressure port is leaking or blocked. If no obvious issues are found, verify the wiring configuration and power supply. If the power is normal, try applying pressure to see if the output changes, or check if the sensor's zero point has an output. If there is no change, it could indicate a damaged sensor, faulty instrument, or a problem with another component in the system.

The second type of failure occurs when the transmitter’s output doesn’t change after pressurization, or when it suddenly drops to zero after pressure is released. This often points to a problem with the sensor’s seal. A common cause is using an incorrect sealing ring that gets compressed into the pressure port during installation, blocking the flow of the pressure medium. When pressure is applied, the medium can't reach the sensor, but once the pressure increases enough, the seal may rupture, causing sudden pressure on the sensor. To resolve this, remove the sensor and check if the zero point is stable. If it is, replace the seal and test again.

The third common issue is unstable output signals from the transmitter. This can be caused by an unstable pressure source, poor interference resistance in the instrument or sensor, or excessive vibration affecting the sensor’s performance. It’s important to investigate all possible sources of instability before concluding that the sensor itself is faulty.

A fourth issue is when the transmitter shows a significant deviation compared to a mechanical pressure gauge. While some deviation is normal, it’s essential to confirm whether the deviation falls within acceptable limits. If not, further calibration or inspection may be needed.

The last common fault involves the installation position of differential pressure transmitters, which can affect the zero output. Due to their small measurement range, the internal sensing elements are sensitive to gravity. During installation, the pressure-sensitive component should be positioned perpendicular to the direction of gravity. After installation, adjust the transmitter’s zero point to the standard value to ensure accurate readings.