Zone 1/ 21 Exhaust Control System
The request
to Extronics was to control 2 exhaust fans, duty and standby, which
would keep the weighbridge pit clear of Hazardous atmosphere.
The control panel was to be fed from 2 different supplies and the main objective was to keep the area clear in the event of any or all of the following fault conditions:-
- Failure/ Shutdown of either incoming power supply
- Failure/ Shutdown of either duty or stand-by fan
- Failure/ Shutdown of either control circuit transformer
Extronics designed the control circuit that if any or all of the above occurred then the appropriate backup would automatically start and sound an alarm and/ or show a remote indicator, maintaining airflow through the hazardous area.
The finished Control Panel was Zone 1/ 21 ATEX certified for use
in a IIB +H2 gas group area and was delivered to the customer
complete with wiring schematics. 
