Each of these sectors is characterized by unique operating conditions, representing a myriad of challenges for pressure measuring instruments to contend with.
Manufacturers of pressure measurement solutions respond to these thermodynamic and chemical challenges by offering a multiplicity of pressure sensors capable of meeting distinct industrial demands. These can be categorised and sub-categorised by their operating technologies and capabilities. Yet this wealth of potential products can appear counterintuitive at first glance. Where do facility operators start when it comes to choosing a pressure sensor?
In this blog post, ABB will be exploring one of the basic concepts of pressure sensors and pressure measurement instruments; the difference between transducers and transmitters.
What are transducers and transmitters?
The term sensor, transducer, and transmitter are often used interchangeably, yet there are subtle technical differences that separate the regularly mistaken nomenclature of mechanical measurement.
In the most basic sense, a pressure sensor is a device used to acquire the quantity of force expressed on a surface area per unit. This is quantified as the necessary value required to stop liquid or gaseous media from expanding. A measuring component, such as a stainless-steel diaphragm, acquires the applied or differential pressure values and the sensor converts the mechanical force into a 4 – 20 mA electrical signal.
This process is largely similar for both pressure transducers and transmitters. The operating principles may be alike, but the capacities of these two pressure sensor types quickly diverge. Transducers measure the expansive force of a process or flow system and generate a relatively low-level electronic signal which corresponds to applied pressure. This is perceived as beneficial from an energy-savings perspective, but it has significant drawbacks with regards to data communication. The range of pressure transducers is limited, and they are typically restricted by a comparative lack of measurement accuracy and compensation capabilities.
Pressure sensors integrated into transmitters are more broadly suited for industrial applications. This is because they are comprised of two primary components; the pressure measurement instrument and a secondary electronics package. These two parts enable direct or indirect acquisition of applied force at one or more points in a system to determine absolute, differential, or multivariable pressure before communicating information through a choice of functional electronics systems. Whether using standard 4 – 20 mA or advanced Profibus communications, pressure sensors can adjust for ambient variations before converting applied measurements into an electronic signal.
This translates into more reliable pressure measurements that are automatically compensated for variations in temperature, for example. Pressure sensors integrated into transducers are usually limited to measuring within a set span, requiring additional process monitoring components to accurately calculate pressure compensated for ambient variables. There are demonstrable drawbacks to using pressure transducers over transmitters from the point of view of both measuring accuracy and operating expenditure.
Pressure sensors from ABB
ABB represents one of the largest selections of pressure sensors worldwide. We have developed an extensive range of pressure transmitters that are equipped to resist chemical attack, ingress from water or process particulates, and damage associated with overpressure conditions.
There are multiple things still to consider once you have decided between a pressure transmitter and a transducer. Read more, with our previous blog post: 4 things to consider when choosing a pressure sensor.
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