[PSUBS-MAILIST] Electronics contents gauge

[Cliff Redus via Personal_Submersibles]

Alan, I agree 100% with Emile on this. Given the safety implications of not
knowing the air pressure in external air tanks, this needs to be a rock
solid measurement.  On my boat, for the HP air pressure, I use a 1/4 MNPT
sensor with a 1-5 vdc analog output screwed into a 316L SS penetrator that
has a 1/4 FNPT thread on the interior side and ANSI 7/16-20 UNF thread on
the exterior.  I use a Swagelok fitting PN SS-400-1-OR that lands in the
penetrator and uses a o-ring face seal.  This fitting converts to 1/4" tube
which I use for all HP air line. 1/4NPT gage pressure sensors are always
available on Ebay with either analog voltage output or analog current
output. This sensor wires directly into PLC analog input module.  PLC
ladder logic can then implement low pressure alarms and interlocks to
prevent diving when air pressure is low or someone forgets to turn on HP
air valve.

Cliff

On Sun, Oct 30, 2016 at 3:19 PM, emile via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> The scuba pressure sensors are wireless. Most scuba divers don’t want it
> as it is unreliable.
>
>
>
> Best would be to screw a industrial pressure sensor (with ¼ “thread or so)
> into the penetrator plate and attach a HP line on the outside.
>
>
>
>
>
> Br, Emile
>
>
>
> *Van:* Personal_Submersibles [mailto:personal_submersibles-
> bounces at psubs.org] *Namens *Alan James via Personal_Submersibles
> *Verzonden:* zondag 30 oktober 2016 21:02
> *Aan:* Personal Submersibles General Discussion
> *Onderwerp:* [PSUBS-MAILIST] Electronics contents gauge
>
>
>
> Is there a suitable electronic scuba tank contents gauge out there?
>
> I am after something that plugs in to the high pressure port of the
>
> 1st stage regulator & has wires off it that I can run through a through
>
> hull so I can display the tank contents pressure on a screen.
>
> Trying to avoid bringing high pressure in to the hull.
>
> An alternative may be to run a high pressure line to a through
>
> hull & have an electronic pressure gauge threaded in to this from the
>
> inside of the hull. However with the second method, I wouldn't have
>
> a shut off valve if the pressure gauge failed some how.
>
> Alan
>
>
>
>
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