Setra Blog

1. Pressure

The first and most important consideration is pressure. A number of questions must be answered to ensure the correct transducer is selected. What is the pressure range that the transducer will measure? What is the maximum pressure the transducer will encounter? What is the potential for over pressure in the system?

Pressure transducers today are more rugged and reliable than ever. Made of stainless steel construction, they provide abundant overpressure protection, improved total error band, and offer negligible orientation and vibration effects. They are ideal for long-term use even in harsh environments of extreme temperature, humidity, and vibration.

The accuracy of differential pressure transducers has greatly improved to provide better solutions for demanding applications. This article discusses why accuracy is an important consideration when selecting a pressure transducer for low-differential, critical pressure applications.

Can’t handle the pressure?

Can you believe that pressure transducers are not always able to handle high pressure? Overpressure, or proof pressure, is a major concern for engineers and OEM designers when assembling machinery and selecting a pressure transducer. Overpressure refers to the maximum pressure value a transducer can withstand without affecting performance; it can also refer to a situation where the pressure value exceeds the limits. Although it is not ideal, pressure transducers can withstand occasional pressures up to their overpressure rating, eventually returning to their natural state. However, pressures that reach burst pressure, the maximum pressure that may be applied to the positive pressure port without physically damaging the internal sensing component, can rupture the diaphragm and cause leakage. Pressures above overpressure but below burst pressure can result in permanent diaphragm deformation, causing an output shift affecting operational performance or accuracy readings.

Below are terms that are associated with use of transducers and electrical equipment in areas which are defined as hazardous by national rating agencies.

Capacitive Transducers

Setra’s capacitive pressure transducers are expertly designed adaptations of a simple, durable and fundamentally stable device...the electrical capacitor. In a typical Setra configuration, a compact housing contains two closely spaced, parallel, electrically isolated metallic surfaces, one of which is essentially a diaphragm capable of slight flexing under pressure. 

Newly Added Restricted Products Under RoHS2 Affects Manufacturing

In 2013, RoHS2 was created by the European Union legislation, nearly a decade after the original RoHS (Restriction of Hazardous Substances Directive) was implemented.  RoHS2 is merely an evolution of RoHS1 that provides greater clarity on the legal scope of products that should adhere to the hazardous material guidelines. The combination of

Total Error Band (TEB) is a measurement of worst case error; it is the most comprehensive and concise measurement of a sensors true accuracy over a compensated temperature range.  TEB is extremely important to know when trying to determine how well a sensor will work within a particular design system. By calculating TEB you'll be able to understand the different possibilities for error. Formulating TEB can be tricky if you don't have the right inputs readily available. 

Happy Halloween From Setra

Have you ever wanted to build your own Haunted House or Spooky Trail?

I'm sure we've all thought about it one time or another. You know what I'm talking about. Places like amusement parks, fairs, or even a homemade one that your “Halloween Crazed” neighbors down the street built themselves. But how do they work?

Absolute pressure is measured relative to a full vacuum (0 PSIA = 14.7 PSIV).  The electrical output of an absolute pressure transducer is 0 VDC at 0 PSIA and full scale output (typically 5 VDC) at full scale pressure (in PSIA).  PSIA (pounds per square inch absolute) is a unit of pressure measured relative to a full vacuum.  A vacuum can refer to any pressure between 0 PSIA and 14.7 PSIA.