AS9120B, ISO 9001:2015, and FAA AC 0056B ACCREDITED

Helping You Decide the Right Instrumentation Device

In the context of electronic communication, automation, and other industrial systems, there are numerous types of instrumentation devices involved, each serving an important role. Oftentimes, components that are similar in structure or function may have terms that are used interchangeably. Unfortunately, this may cause confusion and reduced clarity when discussing purchasing and implementation options. 

In automation applications, it is necessary to measure and detect changes in a physical variable such as force, mass, strain, pressure, velocity, weight, and acceleration; however, it is important to note that some of these variables may comprise others. For example, force in its most simplistic definition is the product of mass and acceleration. Therefore, any instrument used for this purpose must be able to not only measure, but also discriminate between individual characteristics. For the purpose of this discussion, sensors are devices capable of performing initial measurements of these variables. Once changes are detected in the quantity being measured, the mechanical signal is converted into an electrical signal for additional analysis.

In process control, a transmitter is a device that transmits a standard instrumentation signal representing the physical variable being measured. It converts the measurement obtained from a sensor or transducer into a standardized electrical signal, typically 1-5 V or 4-20 mA, which is received by a receiver such as a PLC or DCS. The transmitter ensures that the transmitted signal accurately represents the physical variable. Meanwhile, a switch refers to a device that controls the flow of electrical current based on certain conditions or inputs. It is commonly used to turn on or off electrical circuits or to trigger specific events in an instrumentation system.

As an example of the differences between different instrumentation devices, we will explore the application of pressure measurement. When it comes to pressure measurement, there is a distinction between pressure transmitters and pressure switches. A pressure transmitter converts the pressure measurement into an analog electrical voltage or current signal, while a pressure switch combines a sensing transducer with electrical contacts that open or close at a specific pressure threshold. Pressure transmitters provide continuous measurement and are suitable for applications where precise pressure information is required. On the other hand, pressure switches are designed to trigger specific events, such as opening or closing a valve, when the pressure reaches a predetermined setpoint.

While a pressure transmitter can technically be used as a pressure switch, it is important to consider the practical aspects and requirements of your application. Pressure transmitters are typically larger, more expensive, and may involve more complex installation procedures. On the other hand, pressure switches are simpler, more cost-effective, and easier to install, making them suitable for applications where knowing the exact pressure is not necessary, and only reaching specific pressure points is critical. By correctly identifying the specific requirements of your application and considering factors such as precision, cost, and installation complexity, you can make informed decisions when selecting the most suitable device(s).

Whether you are in the market for precision sensors, transmitters, or other reliable instrumentation components, NSN Catalogue is here to serve as your strategic sourcing partner. With over 2 billion items in our ready-to-purchase inventory, we are confident that you will find a solution fitting your particular requirements. With 24/7x365 support from our team of market experts, get started on the purchasing process today by taking advantage of our Instant RFQ service for any product you are interested in.


December 13, 2022
Semiconductor's Certifications and Memberships
The only independent
distributor with a
  • All Orders are fulfilled in the U.S.A.
  • All shipments must comply with U.S.A export laws.
  • No exceptions.
Intrepid Fallen Heroes Fund

“We Proudly Support Intrepid Fallen Heroes Fund that serves United States Military Personal experiencing the Invisible Wounds of War : Traumatic Brain Injury (TBI) and Post Traumatic Stress (PTS). Please visit website ( and help in their valiant effort”.

Thank You for Visiting.

We Hope that You Will Visit Us Again the Next Time You Need NSN Parts and Make Us Your Strategic Purchasing Partner.

Request for Quote

We use cookies to ensure that we give you the best experience on our website. If you continue to use this site we will assume that you are happy with it.