VR3 missed stop after 5 minutes in 10 feet

ERIK_A · 15th October 2006, 17:54

I got a real wierd reading off my VR3 yesterday. Dive one. I was a quarry dive yesterday. Nothing real challenging but I was taking my decent real slow. After 5 minutes, I was at ten feet and still decending and my VR3 said Missed stop use tables. It doesnt make a lot of sense to me. I continued to use it as a depth guage and timer. Finished my dive with the message still on the screen.

Additionally when I calibrated everything on the surface my VR3 and my oxyguage sensors where reading the same FO2 when I dove I was getting to different PPO2s. The Oxyguage was more conservative sometimes by .03 but as high as .06. This was in 30 feet of water Is the VR3 normally less conservative or am I making a big deal in my mind out of nothing? Just curious. These where my first time diving with both the OXY and the VR3 in the bag and never noticed the difference before.

Anyone seen either of these happen?

Deepthought · 15th October 2006, 19:48

There's a chinese proverb "A man who has a watch knows what time it is. A man with two watches is never sure"

At around 30 feet (OK I'm going to use metric equivalent of around 10 meters) ambient pressure is 2 atm so a ppO2 difference of .06 is like 3 percent difference in O2 concentration.

Are both sensors in the same bag? depending on where in the loop extra gas is added could be a possible?

How old are the each of the cells and are they genuine or third party?
Look at this link
Oxygen Sensors - Diving Industry

You'll see that both the D02 and D06 would fit the oxygauge but one is 6mV and other only 5 - wrong sensor = upto 20% error

Sorry but I don't know what you're diving but it might be a good diagnostic to calculate expected ppO2 at a given depth - this will give a good idea if one is right and the other is low (or high) or if they are both a little off.

e.g. on an SCR at 10m (2atm) on 40% nitrox, a loop flush would give theoretical ppO2 of 0.8

Not a lot of experience with the VR3 but some dive computers I've had in the past did get inaccurate on depth if salt built up around the depth transducer - stick it in a jar of fresh water for a few days.

I think the VR3 turns off above 3m - I did a dive with a guy in the shallows for about 70 mins and his vr3 logged it as only 22 mins.

ERIK_A · 15th October 2006, 21:38

Quote: (Originally Posted by Deepthought)

There's a chinese proverb "A man who has a watch knows what time it is. A man with two watches is never sure"

AINT THAT THE TRUTH...

Quote: (Originally Posted by Deepthought)

At around 30 feet (OK I'm going to use metric equivalent of around 10 meters) ambient pressure is 2 atm so a ppO2 difference of .06 is like 3 percent difference in O2 concentration.

Are both sensors in the same bag? depending on where in the loop extra gas is added could be a possible?

How old are the each of the cells and are they genuine or third party?
Look at this link
Oxygen Sensors - Diving Industry

You'll see that both the D02 and D06 would fit the oxygauge but one is 6mV and other only 5 - wrong sensor = upto 20% error

Sorry but I don't know what you're diving but it might be a good diagnostic to calculate expected ppO2 at a given depth - this will give a good idea if one is right and the other is low (or high) or if they are both a little off.

e.g. on an SCR at 10m (2atm) on 40% nitrox, a loop flush would give theoretical ppO2 of 0.8

Yeah both sensors are in the same bag and only about a inch apart. Which is why I was surprised at the readings the are both new. I popped them out of the bag the same day. The are both correct for the application. That is why the difference kind of surprised me. I guess I might have to buy a couple new ones to see what the deal is.

Quote: (Originally Posted by Deepthought)

Not a lot of experience with the VR3 but some dive computers I've had in the past did get inaccurate on depth if salt built up around the depth transducer - stick it in a jar of fresh water for a few days.

I think the VR3 turns off above 3m - I did a dive with a guy in the shallows for about 70 mins and his vr3 logged it as only 22 mins.

It does turn off above 5 feet at least thats what I have noticed however Im not sure why it would do this error message on initial decent. The VR3 has been in freshwater exclusively for about the last 40 dives.

Any other ideas?

grahamsp · 16th October 2006, 07:20

Quote: (Originally Posted by ERIK_A)

I got a real wierd reading off my VR3 yesterday. Dive one. I was a quarry dive yesterday. Nothing real challenging but I was taking my decent real slow. After 5 minutes, I was at ten feet and still decending and my VR3 said Missed stop use tables. It doesnt make a lot of sense to me.

I had a similar problem tho' it was on ascent not descent. Turned out to be due to a low battery. Swapped old for new and the problem disappeared.

Graham

ERIK_A · 16th October 2006, 09:01

Now that I will check on as well.

Deepthought_reloaded · 18th October 2006, 01:37

Hello,

been having a few problems with my registration - ended up re registering.

Was going to ask if you have access to 'pure' oxygen - fill the bag (jury rig with clingfilm) and see which one reads ppO2 of (nearly) 1.00

The battery could easily explain the 'off' reading - presume the o2 measurement is some form of voltage comparison between the internal VR3 battery and the voltage produced by the Oxygen cell - in theory would mean a low VR3 battery would give a falsely high o2 reading.

Cheers

Deepthought AKA (Deepthought_reloaded)

15th October 2006, 17:54	#1 (permalink)
ERIK_A New Member Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Dec 2005 Location: on O2 at 20 feet Posts: 60	VR3 missed stop after 5 minutes in 10 feet I got a real wierd reading off my VR3 yesterday. Dive one. I was a quarry dive yesterday. Nothing real challenging but I was taking my decent real slow. After 5 minutes, I was at ten feet and still decending and my VR3 said Missed stop use tables. It doesnt make a lot of sense to me. I continued to use it as a depth guage and timer. Finished my dive with the message still on the screen. Additionally when I calibrated everything on the surface my VR3 and my oxyguage sensors where reading the same FO2 when I dove I was getting to different PPO2s. The Oxyguage was more conservative sometimes by .03 but as high as .06. This was in 30 feet of water Is the VR3 normally less conservative or am I making a big deal in my mind out of nothing? Just curious. These where my first time diving with both the OXY and the VR3 in the bag and never noticed the difference before. Anyone seen either of these happen? __________________
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15th October 2006, 19:48	#2 (permalink)
Deepthought New Member Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Jan 2006 Location: York Posts: 24	Re: VR3 missed stop after 5 minutes in 10 feet There's a chinese proverb "A man who has a watch knows what time it is. A man with two watches is never sure" At around 30 feet (OK I'm going to use metric equivalent of around 10 meters) ambient pressure is 2 atm so a ppO2 difference of .06 is like 3 percent difference in O2 concentration. Are both sensors in the same bag? depending on where in the loop extra gas is added could be a possible? How old are the each of the cells and are they genuine or third party? Look at this link Oxygen Sensors - Diving Industry You'll see that both the D02 and D06 would fit the oxygauge but one is 6mV and other only 5 - wrong sensor = upto 20% error Sorry but I don't know what you're diving but it might be a good diagnostic to calculate expected ppO2 at a given depth - this will give a good idea if one is right and the other is low (or high) or if they are both a little off. e.g. on an SCR at 10m (2atm) on 40% nitrox, a loop flush would give theoretical ppO2 of 0.8 Not a lot of experience with the VR3 but some dive computers I've had in the past did get inaccurate on depth if salt built up around the depth transducer - stick it in a jar of fresh water for a few days. I think the VR3 turns off above 3m - I did a dive with a guy in the shallows for about 70 mins and his vr3 logged it as only 22 mins. Last edited by Deepthought : 15th October 2006 at 20:12. Reason: missed out link
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15th October 2006, 21:38	#3 (permalink)
ERIK_A New Member Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Dec 2005 Location: on O2 at 20 feet Posts: 60	Re: VR3 missed stop after 5 minutes in 10 feet Quote: (Originally Posted by Deepthought) There's a chinese proverb "A man who has a watch knows what time it is. A man with two watches is never sure" AINT THAT THE TRUTH... Quote: (Originally Posted by Deepthought) At around 30 feet (OK I'm going to use metric equivalent of around 10 meters) ambient pressure is 2 atm so a ppO2 difference of .06 is like 3 percent difference in O2 concentration. Are both sensors in the same bag? depending on where in the loop extra gas is added could be a possible? How old are the each of the cells and are they genuine or third party? Look at this link Oxygen Sensors - Diving Industry You'll see that both the D02 and D06 would fit the oxygauge but one is 6mV and other only 5 - wrong sensor = upto 20% error Sorry but I don't know what you're diving but it might be a good diagnostic to calculate expected ppO2 at a given depth - this will give a good idea if one is right and the other is low (or high) or if they are both a little off. e.g. on an SCR at 10m (2atm) on 40% nitrox, a loop flush would give theoretical ppO2 of 0.8 Yeah both sensors are in the same bag and only about a inch apart. Which is why I was surprised at the readings the are both new. I popped them out of the bag the same day. The are both correct for the application. That is why the difference kind of surprised me. I guess I might have to buy a couple new ones to see what the deal is. Quote: (Originally Posted by Deepthought) Not a lot of experience with the VR3 but some dive computers I've had in the past did get inaccurate on depth if salt built up around the depth transducer - stick it in a jar of fresh water for a few days. I think the VR3 turns off above 3m - I did a dive with a guy in the shallows for about 70 mins and his vr3 logged it as only 22 mins. It does turn off above 5 feet at least thats what I have noticed however Im not sure why it would do this error message on initial decent. The VR3 has been in freshwater exclusively for about the last 40 dives. Any other ideas? __________________
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16th October 2006, 07:20	#4 (permalink)
grahamsp New Member Current Rebreather/s: Evolution Other Rebreather/s: Join Date: Jun 2005 Location: Sydney, Australia Posts: 117	Re: VR3 missed stop after 5 minutes in 10 feet Quote: (Originally Posted by ERIK_A) I got a real wierd reading off my VR3 yesterday. Dive one. I was a quarry dive yesterday. Nothing real challenging but I was taking my decent real slow. After 5 minutes, I was at ten feet and still decending and my VR3 said Missed stop use tables. It doesnt make a lot of sense to me. I had a similar problem tho' it was on ascent not descent. Turned out to be due to a low battery. Swapped old for new and the problem disappeared. Graham
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16th October 2006, 09:01	#5 (permalink)
ERIK_A New Member Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Dec 2005 Location: on O2 at 20 feet Posts: 60	Re: VR3 missed stop after 5 minutes in 10 feet Now that I will check on as well. __________________
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18th October 2006, 01:37	#6 (permalink)
Deepthought_reloaded New Member Current Rebreather/s: Azimuth Other Rebreather/s: Azimuth Join Date: Oct 2006 Location: York Posts: 59	Re: VR3 missed stop after 5 minutes in 10 feet Hello, been having a few problems with my registration - ended up re registering. Was going to ask if you have access to 'pure' oxygen - fill the bag (jury rig with clingfilm) and see which one reads ppO2 of (nearly) 1.00 The battery could easily explain the 'off' reading - presume the o2 measurement is some form of voltage comparison between the internal VR3 battery and the voltage produced by the Oxygen cell - in theory would mean a low VR3 battery would give a falsely high o2 reading. Cheers Deepthought AKA (Deepthought_reloaded)
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