Mv output on new Bud R22 Cells?

SimonK · 5th June 2006, 22:19

Mark

With my diagnostic skills suitably sharpened by Highland Park-

My first reaction to the numbers you posted at the start was 'you screwed up, go away and do it again'

However if you are confident that you get repeatable data from the old and new cells then the new cells appear to be bad. Its not just a matter of of the cells being at the low end of the manufacturers tolerance band, its back to the multiplication by 4.7 between air and O2. A cell that reads 9mV in air should read 42mV in O2 not 35mV.

When you are chasing this sort of thing it is really important that you do exactly the same test on each item. Its also important to do each test a couple of times to reassure yourself that your not screwing it up.

I know I'm stating the obvious but (from bitter experience) its amazing how many times the obvious gets overlooked when we start chasing a problem.

Simon

***jradomski*** · 5th June 2006, 23:43

Quote: (Originally Posted by heyydude)

Other CCR electronics allow divers to calibrate at LESS than 100% - Trying to be Polite, and with All Due Respect, WE DO NOT agree with this philosophy. In our Humble Opinion, there are TOO MANY ways a diver can wind up dead using that scenario, and we are not willing to allow our set to do that. Why would anyone trust a $50 "El Cheapo" O2 analyzer (no offence to my great friend, Pat Duffy), which is calibrated in AIR vs, a multi-thousand dollar piece of CCR electronics is beyond me.

And before anyone jumps down my throat about this - remember, the USN, RN and RAN all use Medical or Aviator Grade O2, and flow 4 lpm around their R-10D's for FOUR MINUTES before calibrating. I don't know any civilian that does that - but more of you should. It is a good policy. Gas is CHEAP compared to LIFE.

Joe Radomski and I have had this discussion/argument more times than I can count, but I still come back to the same thing - if you want to actually dive something less than 100% O2, you can always compensate via your Set-Point control and your Conservatism - giving you the actual mV output of each cell should be sufficient to help you calculate using a very precise instrument (the HH) what actual FO2 your O2 bottle has in it.

And, most importantly, 3 years of experience has borne out that the 40 mV limit WORKS.

.

Its been a while... Aren't we do for another round?

Talk to ya soon

PCDiver · 6th June 2006, 05:32

Quote: (Originally Posted by jradomski)

Its been a while... Aren't we do for another round?

I think I can come up with additional suggestions for new features: battery voltage display at startup, optional selection of activation by wetswitches/depth sensor, ...

Mark Chase · 6th June 2006, 07:22

Wow am I going to get a bollocking for my little report on the HH

Thanks for the detailed lesson Kevin. I will do my best to follow your advice.

ATB

Mark Chase

Gilles · 6th June 2006, 09:12

Could I bother Kevin J and Joe R to review the below post (if not already) and provide opinion. Your sensor expertise's may be valuable here as well.

Thanks in advance.

Gilles

http://www.rebreatherworld.com/megal...onitoring.html

sensor330 · 11th June 2006, 05:21

Are the rest of you HH users getting the same MV readings on both handsets? Just wondering because I'm not but there close though.

Scott

5th June 2006, 22:19	#11 (permalink)
SimonK Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Oct 2005 Location: Cumbria UK Posts: 231	Re: Mv output on new Bud R22 Cells? Mark With my diagnostic skills suitably sharpened by Highland Park- My first reaction to the numbers you posted at the start was 'you screwed up, go away and do it again' However if you are confident that you get repeatable data from the old and new cells then the new cells appear to be bad. Its not just a matter of of the cells being at the low end of the manufacturers tolerance band, its back to the multiplication by 4.7 between air and O2. A cell that reads 9mV in air should read 42mV in O2 not 35mV. When you are chasing this sort of thing it is really important that you do exactly the same test on each item. Its also important to do each test a couple of times to reassure yourself that your not screwing it up. I know I'm stating the obvious but (from bitter experience) its amazing how many times the obvious gets overlooked when we start chasing a problem. Simon
(Online)

5th June 2006, 23:43	#12 (permalink)
*jradomski* Moderator Current Rebreather/s: Inspiration Classic Sport Kiss Optima rEvo Other CCR Home Build Other Rebreather/s: Inspiration Vision Evolution Megalodon Classic Kiss rEvo Other CCR Home Build Join Date: Mar 2005 Location: "Da" Bronx Posts: 2,890	Re: Mv output on new Bud R22 Cells? Quote: (Originally Posted by heyydude) Other CCR electronics allow divers to calibrate at LESS than 100% - Trying to be Polite, and with All Due Respect, WE DO NOT agree with this philosophy. In our Humble Opinion, there are TOO MANY ways a diver can wind up dead using that scenario, and we are not willing to allow our set to do that. Why would anyone trust a $50 "El Cheapo" O2 analyzer (no offence to my great friend, Pat Duffy), which is calibrated in AIR vs, a multi-thousand dollar piece of CCR electronics is beyond me. And before anyone jumps down my throat about this - remember, the USN, RN and RAN all use Medical or Aviator Grade O2, and flow 4 lpm around their R-10D's for FOUR MINUTES before calibrating. I don't know any civilian that does that - but more of you should. It is a good policy. Gas is CHEAP compared to LIFE. Joe Radomski and I have had this discussion/argument more times than I can count, but I still come back to the same thing - if you want to actually dive something less than 100% O2, you can always compensate via your Set-Point control and your Conservatism - giving you the actual mV output of each cell should be sufficient to help you calculate using a very precise instrument (the HH) what actual FO2 your O2 bottle has in it. And, most importantly, 3 years of experience has borne out that the 40 mV limit WORKS. . Its been a while... Aren't we do for another round? Talk to ya soon __________________ Joe Radomski CCR Trimix Instructor Trainer ANDI Instructor Trainer Director #10 All posts are personal opinions and DO NOT reflect any affiliated agency unless specifically stated.
(Online)

6th June 2006, 05:32	#13 (permalink)
PCDiver Submerge Productions Current Rebreather/s: Inspiration Vision Other Rebreather/s: Inspiration Classic Join Date: Feb 2005 Location: Belgium Posts: 937	Re: Mv output on new Bud R22 Cells? Quote: (Originally Posted by jradomski) Its been a while... Aren't we do for another round? I think I can come up with additional suggestions for new features: battery voltage display at startup, optional selection of activation by wetswitches/depth sensor, ...
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6th June 2006, 07:22	#14 (permalink)
Mark Chase I go down for ages Current Rebreather/s: Classic Kiss Other Rebreather/s: Inspiration Classic Join Date: Jan 2005 Location: Kent Posts: 2,558	Re: Mv output on new Bud R22 Cells? Wow am I going to get a bollocking for my little report on the HH Thanks for the detailed lesson Kevin. I will do my best to follow your advice. ATB Mark Chase __________________ Is it supposed to make that noise ? I took my unit to the dive shop and demanded they bolt on every thing that would fit. Join my elite diving teem and get a Tshirt "Doing It Chasey"Hammerhead Eccr Advanced Diving System
(Online)

6th June 2006, 09:12	#15 (permalink)
Gilles Worship the feminine Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Sep 2005 Location: Den Haag (Netherlands) Posts: 762	Re: Mv output on new Bud R22 Cells? Could I bother Kevin J and Joe R to review the below post (if not already) and provide opinion. Your sensor expertise's may be valuable here as well. Thanks in advance. Gilles http://www.rebreatherworld.com/megal...onitoring.html __________________ Gilles http://www.dirrebreather.com
(Offline)

11th June 2006, 05:21	#16 (permalink)
sensor330 Custom Title Allowed! Current Rebreather/s: Megalodon Other Rebreather/s: Not Bought Yet Inspiration Classic Join Date: Feb 2005 Location: Victoria, British Columbia, Canada Posts: 561	Re: Mv output on new Bud R22 Cells? Are the rest of you HH users getting the same MV readings on both handsets? Just wondering because I'm not but there close though. Scott
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