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Simplifying Complexity. Delivering Safety.
Simplifying Complexity.
Delivering Safety.

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Making a non-certified HMI suitable for use in a hazardous area



Working with a client specializing in the manufacture of pump and air compressor packages for oilfield and industrial applications who needed a hazardous area solution for an existing system design. 


Project Brief

To design and engineer a custom operator interface adaptor for specified non-rated HMI (Human Machine Interface). Using the HMI replaced the function of most of the pilot devices (buttons and lamps) on the compressor control panel. This was desirable as the client’s packaged skid was required to meet hazardous area requirements (generally Class I, Division 2).


  • Customer specified HMI is not hazardous area rated and minimal environmental or ingress protection rating
  • Limited envelope or space in the control enclosure to fit HMI and operator interface adaptor.
  • Complete membrane key functionality required, as well as being able to view of small, two-line LED display on HMI.


Expo's Solution & Outcome
  • Custom operator interface adaptor to fit specified HMI. 
  • Environmental and Ingress protection compliant to maintain integrity of customer’s control enclosure
  • Compatible operation for use with type Z purge and pressurization system.
  • Client now has a solution to pursue more business opportunities with Class I, Division 2 hazardous area requirements
Expo products and services
  • Consultancy and engineering services for the design work of the operator interface adaptor.
  • Operator Interface Adaptor kit

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