Quote: (Originally Posted by
Mark Chase)
I dont understand this?
I have a milivolt display and a PP02 display on my Shearwater but on my KISS displays i only have a PP02 display?
If the KISS only displays PP02 it that information not "Processed"
How is the data procesed on the Shearwater before it is displayed as milivolts?
I asumed MV was just MV???
I found this an advantage on both the Shearwater and the Hammer Head displays.
ATB
Mark
The data going to the Shearwater is going to through some sort of digital processing before it is displayed. The mV, even though is raw data, is still having to go through some sort of processing, it's the same piece of data just being shown in a different format. It isn't verifying anything, it's the same data shown in a different way. If my display is displaying 1.00 then I might wonder if this is correct and switch to the mV reading. Aha... it's reading 48mV... that sounds near enough for a 1.00 PO2! But it's a false reassurance, it's still that same signal going through that same processor but shown in a different format.
The KISS display is essentially unprocessed. It takes the raw millivoltage and displays that. By setting the calibration pot all you are doing is moving the display range forwards and backwards along a sliding scale from 0-199. The cells are outputting, say 10-50mV at the surface, adjusting the pot just makes the starting point 20 instead of 10. The decimal point is preset and doesn't come into it. OK, there is some processing to get it on the display but it is an extremely basic circuit designed for the process industry which (I would hope) would be fault tolerant to industrial standards. Plus you've got three of them. OK, they are monitoring different things but that's what your brain is for. Compare the readings and come to a decision.
The Shearwater has taken me out of that loop, it is letting me see what it is wanting me to see, and it's processing it all in one place. For my philosophy, that's a bad thing and I'm not comfortable with no alternative way of verifying what is on my display. The triple independant display goes a lot further to do that, I have three individual systems that I can make a judgement on. It's not bombproof but I prefer it to an unverifiable single display. I could add a HUD but if I have a "processed" display then I want something unprocessed that puts me right in the middle of what is happening.
That's just my philosophy, other people may or may not be as uncomfortable in that approach as I am. I'm not saying it's good or bad, it's what I'm comfortable with.
Cheers,
Stuart