When you’re dealing with pressure measurement, there is little room for error. There are a host of dangers waiting in the shadows of incorrect pressure sensor selection, installation, and application. To help you avoid these risks, our experts at Automation Products Group, Inc. (APG) have identified five common pressure measurement challenges, along with solutions to help ensure you’re set up for success.
Since pressure transmitters are contact sensors, they must be in contact with the target media in order to function. Therefore, chemical compatibility is crucial.
The sensor’s wetted material is the key component of chemical compatibility. 316L SS is a common offering, but it’s not compatible with all substances. Lean on your MSDS and compatibility charts to ensure you select the right materials for your application.
APG offers a new PT-503 submersible pressure transducer crafted out of advanced materials like PVDF, providing a reliable alternative to stainless steel, and enabling accurate measurements in harsher chemical environments.
A standard piezoresistive pressure sensor’s accuracy is based on the pressure range. The error band is a percentage of the full scale range (our standard is ±0.25% of full scale) and the sensor’s accuracy is dependent on the original full scale range. A sensor measuring over 150% of your expected range diminishes your accuracy, and sensors measuring above their full scale range will overstress the diaphragm and destroy the calibration.
To avoid this, match your sensor’s pressure range as closely as possible to what you expect to measure. For instance, if you’re measuring up to 100 psi, a 10,000 psi sensor would be overkill and compromise your readings.
A pressure transducer’s sensing element is a very thin diaphragm with electronics mounted on the back. The electronics on the back of the diaphragm react consistently as pressure rises and falls. The diaphragm is susceptible to careless handling and compression during installation. Compression is a result of applying too much torque when installing the sensor. Overtightening the sensor compresses the diaphragm and changes its shape. The diaphragm won’t react to the pressure as expected.
To prevent this, exercise care when installing your pressure transducer and avoid overtightening. Proper installation torque is the key to maintaining the sensor’s integrity.
Sealed sensors are advantageous for keeping fine particles out of the sensor’s electronics. A sealed sensor uses a closed chamber as its reference (zero) point, while a vented sensor uses atmospheric pressure. As the atmosphere’s pressure changes with the weather, the closed chamber expands and contracts. This moves the zero point around and interferes with your pressure measurement. In high pressure ranges, this falls within the stated error band on the sensor and is unnoticeable. In low pressure applications, a sealed pressure sensor becomes problematic. The changing atmospheric pressure acts on the sealed chamber inside the sensor, causing unreliable measurements.
In low pressure applications, opt for gauge sensors or vented sensors to ensure reliable readings and avoid atmospheric interference.
Applying the wrong voltage can cause sensor failure. For example, a 110V wired to a sensor designed for 24V won’t operate successfully, nor will the sensor operate if the AC current is applied to a sensor that needs DC.
Know your sensor’s voltage and current limitations before installation. Become familiar with the sensor’s wires and where to connect them. Proper knowledge of wiring and connections will ensure a smooth and successful installation.
Contact us to ensure you’re selecting, installing, and using your pressure sensors with confidence. Our team at APG is here to help you achieve precise, reliable pressure measurements every time.
