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
The definition we (and the Technical Committee of the CE) give to “active warning device” is the following:
A: a device that gives a warning to the user, in case of an event, without the user having to do any effort to receive the warning
B: warning meaning: changing from one state to the other when going from OK to NOT OK
Criteria A: buzzer, light in front of the eye, … is ok
light or display clipped somewhere, so that the user must take action to look at it…not ok
Criteria B a PP02 indicator in front of the eye: not ok: as there is not change of state when the event occurs, and the memory will wipe out the signal after some time
A HUD where a light starts or goes out when the event happens, combined with flashes or whatever = ok as a “change in state” is noticed
We are currently still developing our online spares store. Until then, you can contact rEvo Rebreathers Head Office.