How to: Selecting a Pressure Sensor/Transducer/Transmitter

June 22, 2018

Pressure sensors/transducers/transmitters are offered with a wide variety of configurable options, sizes and approvals. This can make selecting the proper pressure sensor for your application difficult. The following are key features of a pressure sensors design/construction that need to be considered to help narrow down the selection and ensure the most appropriate sensor is selected:

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Mechanical Interface

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Electrical Interface

Mechanical Interface

The mechanical interface, also referred to as the process connection, is how the sensor is connected to the pressure source (see photo above). This is typically done via a threaded connection. Core Sensors offers a wide range of thread types including NPT, SAE/UNF, BSP, DIN and Metric. Male and female versions are available. Certain factors may limit the availability of the process connections including material requirement and pressure range. Custom connection options are available upon request. Core Sensors can also offer thread adapters upon request.

Pressure Range

Core Sensors offers pressure ranges from 1 PSI up to 40,000 PSI. Compound (i.e. -14.7 to 100 PSI) and bi-directional (i.e. -10 to +10 PSI) pressure ranges are offered for applications such as water pumps to measure suction and discharge and vapor recovery in landfills. It is important to note if your application will produce sudden pressure spikes/water hammer. These spikes are common in hydraulic applications such as a forklift suddenly dropping its load to the ground and a fast closing valve while fluid is still flowing. These pressure spikes can surpass the operating pressure of the sensors diaphragm and, at a minimum, cause permanent shifts in the sensors output. Core Sensors offers configurations to combat these over pressure conditions.

Electrical Interface

The electrical interface, also referred to as the electrical connection, is how the output signal is transmitted to a PLC or other instrumentation (see photo above). Electrical connection options include integral cable, connector or inline connector. Customers can choose from connectors such as DIN 43650-A and C, M12x1, Packard Metripack 150, 6-Pin Bendix, Deutsch DT04 3 Pin and 4 Pin and others. Certain product families have a limited selection of options due to hazardous certifications and design limitations. Wire-to-cable connectors are available in-line installed directly at the sensor for retrofit applications. Custom configurations are available upon request.

The environment where the sensor will be installed should be considered. Different connection types offer different ingress protection (IP) ratings. Core Sensors will help guide you on the best electrical interface based on your installation environment.

Power Supply/Output Signal

The available power supply, sometimes referred to as the Excitation Voltage or Supply Voltage, is an important consideration. Core Sensors offers  products that will operate from voltages as low as 3VDC for remote telemetry applications all the way up to 28VDC.

Determining the available power supply will help narrow the output signal options. For long distance transmissions, Core Sensors recommends a 4-20mA output signal which can operate off of an unregulated 10-28VDC excitation voltage. High level voltage output signals are also available which offer low current consumption. These voltage output signals are not recommended for transmissions over 20 feet. There are multiple voltage signals available requiring different power supplies. For example, a 1-5V output signal requires a 10-28VDC unregulated power supply while a 0.5-4.5V ratiometric output signal requires a regulated 5VDC power supply.

Click here to learn more about the output signals that are available from Core Sensors: Current, Voltage, Millivolt 

Process Media

The process media is the gas/liquid in the application whose pressure is being measured. Understanding the process media will help guide the selection of the mechanical interface material. Common material choices include stainless steel (17-4PH and 316L), exotic alloys (Hastelloy C276 and Inconel 718) and titanium 6-4.

Approval Requirements

Understanding any approvals/certifications that are required in your installation will help guide you to the appropriate pressure sensor product family. Core Sensors currently offers CE marking on most of its products and North American CSA certifications for Class 1, Div 1 Intrinsically Safe and Class I, Division 2 Non-Incendive installations.

Identifying your requirements and preferences will greatly simplify the process of selecting the most suitable pressure sensor for your application. Call us today at (862) 245-2673 to discuss your application.