Written by: Direct Pneumatics

Pressure Switches, Transducers, and Transmitters

Pressure feedback devices are one of the most commonly used fluid control components. Uses include a variety of industry segments, e.g. automotive, Food and Packaging, Medical Devices, Pharmaceutical as well as many other industries. Whenever gases or liquid are used, there’s almost always a need to control the pressure.

Today, Barksdale manufactures a wide variety of solid-state pressure switches having one to four or more switch points, digital displays, analog, and digital outputs, as well as full programmability through an accessible keypad.

The figure below shows a diagram of a simple solid-state pressure switch without enhancements. In many cases, they cross the line from being simply a switch to an open-loop controller.

In addition to opening or closing the pressure switch circuit(s), they provide a proportional analog 4-20 mA signal or digital 0-10vdc output. The analog signal can interface with PLCs (Programmable Logic Controls), DCSs (Distributed Control Systems), and computers.

Solid-state pressure switches provide a number of advantages over electromechanical switches, including:

  • Much longer cycle life
  • Improved accuracy to ±0.25%
  • High resistance to shock and vibration
  • The ability to handle a wide range of system pressures
  • Broad frequency response
  • Excellent long-term stability.

Choosing the right switch for the application

The most important factor in selecting a pressure switch is to fully understand your requirements before beginning the selection process. Armed with that knowledge, you must consider a number of parameters in making a final selection.

Some of the questions to ask are:

  • What type of pressure sensor, digital discrete switch, or with a variable analog signal?
  • What are the cycle speeds and life expectancies?
  • What are the pressure ranges, accuracy, and proof pressure?
  • What is the number of switch points needed?
  • Dead-band, hysteresis requirements?
  • Environmental needs for your housing type, IP65, IP67, etc… or wetted materials?
  • Do you need adjustable or nonadjustable set points?
  • Should the switch be electromechanical or solid-state?

For more information click here: Direct Pneumatics