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Carl Heinzl writes: >>One point I haven't seen mentioned in regard to air integrated computers >>is the inability to do a simple check of whether your air is turned on >>sufficiently. > >Why? > >>With an analog gauge, a standard pre-dive check is to breathe off a reg >>while watching for needle movement. If the needle moves, then the tank is >>not turned on fully. > >Yes. > >>With a digital gauge, you cannot do this. This is the one major problem I >>find with my air integrated computer (a Suunto EON). > >Of course not, there's no needle. But, if you look at the pressure before >and after you've done your test breaths it should be quite obvious if the >pressure has dropped. I was not talking here about the case where the lines have been presurised and then the tank turned off, but rather the classic case of when a diver turns the tank all the way OFF and back half a turn instead of all the way ON and back half a turn. In this case, the air flow is severely restricted and sucking on a reg will cause a transient pressure drop in the high pressure side of the 1st stage. This registers on an analog gauge as a transient deflection of the needle. On a digital gauge, the sampling interval is such that such transients are not seen. One would need to take quite a few breaths to see a noticeable drop in the pressure reading and we wouldn't want to waste that air would we ! A tank which is only partially on can be quite a hazard at depth when the demanded air flow increases. Your points about getting used to digital gauges are valid though! Cheers, David. ______________________________________________________________________________ David Giddy, | Voice: +61 3 253 6388 Telstra Corporation, | Fax: +61 3 253 6144 P.O. Box 249, Clayton, Victoria 3168, AUSTRALIA | Net: d.giddy@tr*.oz*.au* X400: g=david s=giddy ou=trl o=telecom prmd=telecom006 admd=telememo c=au ------------------------------------------------------------------------------
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