[PSUBS-MAILIST] (no subject)

[Jon Wallace via Personal_Submersibles]

I like the autopilot feature for depth control, but one little nit that 
may mess things up from an observation perspective is the accuracy of 
the pressure gauge.  It looks like I'm going to have an overall  +/- 6 
feet accuracy based upon full scale accuracy on a 500 psi sensor.  So 
relying on the microprocessor to maintain depth means a potential 6 foot 
vertical drift in either direction.  Operationally not an issue but if 
your observing something and need to stay still to capture photo or 
video you may still need to provide manual input if not perfectly buoyant.

Jon


On 8/28/2015 7:57 AM, Sean T. Stevenson via Personal_Submersibles wrote:
>
> I'd be inclined to link the two systems, such that you catch a trim 
> with the VBT upon initial submersion, drive down with thrusters, and 
> then at your operating depth, have a controller (PAC or PLC) maintain 
> that depth automatically using thrusters, but simultaneously 
> auto-adjust the VBT level to bring the required thruster output back 
> to zero.  That way they're never fighting the vessel's buoyancy and 
> you maximize battery endurance.
>
> Sean
>
>