Why is a connector (Fisher) on a controller system never allowed?

Electric signals in a rebreather are mostly of one of the following type:

  • Very low voltage and current: the signals from the oxygen sensors – mostly millivolts and micro amp
  • Medium voltage and current: the battery for the solenoid – current going the through the solenoid: 6V-12V and from 0.1 up to >1 amp (peek) when the solenoid fires

The difference in voltage and current between the 2 types are in general the range of 1 to 10.000-100.000 (so 4 to 5 magnitudes!!)

When using a controller, both those signals generally go through the same cables, and if correctly shielded that is not a problem.

However when using a connector in this cable system, and that connector is not 100% perfect, the slightest humidity or dirt into the connection system will cause interference between the “high voltage/current” lines and the sensor reading lines and will destroy the signals of the last

As practice shows that a connector is never maintained so perfectly that there is not the slightest risk of this interference, ever manufacturer uses hard-wired connections on their controllers

If you have any other questions or would like more information on Controller Connections then please do not hesitate to contact us