Calibrating the VR3 O2 Sensor

tamorgen · 28th April 2008, 09:04

Hi all,
I bought my VR3 last year when I bought my Dolphin to use it to monitor FO2. I have the C9 code (External O2 Sensor), as well as up through C4(CCR & Trimix) I've never had a lot of luck of getting an accurate reading of the FO2, but I went out this weekend for the first dive trip of the season, with brand new sensors, and this has got to take the cake.

I hooked up the new sensor, and I went to calibration mode. First off, please note I am using it in semi-closed mode, so Xo2 and XDec are both on. Apparently, it took me a little while to figure out, but this sets the VR3 into calibrating the sensor as per CCR mode. Is this what everyone else has noticed?

When I tried calibrating it, I thought it was supposed to calibrate off of air. Well, I tried doing this, and after calibration, it was reading air as 32%. Doesn't quite seem right, does it? I would turn my mix on (38%), and the VR3 would read around 50%. Definately not right. I tried a different, brand new sensor, and I got the same result. I turned off XDec and dove it as table inspiration, and got off the boat.

That night, I was reading the manual, and it occured to me to that CCR wants to calibrate via 100% O2 (it tells me to Flush with my calibration mix). So, one of the guys I was diving with had his 13 cu ft O2 bottle for his Optima, so I hooked up the sensor to his bottle, and started the calibration processs all over. The VR3 started calibrating the O2 at 161%, but then I told it to calibrate, it reverted down to 100%, and I thought I was good to go. I stopped flushing, pulled it away (after all calibrated), and it said 21% (air), so I thought I was good to go.

Yesterday morning I go out to the boat, and hook up everything, and I think everything is good to go. I plug my VR3 back in to my Dolphin, and it's reading 9% FO2 off of my 37% mix. At this point, I'm like WTF!? So, I again turn off XDec and dive it via the tables.

Two things: 1) Can anybody tell me what I'm doing wrong? 2) Can the folks at VR3 kindly write the manual to explain to us using the VR3 in semi-closed mode that you may have to calibrate it via CCR calibration mode? I just about wanted to through the computer over the side this weekend. It was extremely frustrating. Keep in mind that I tried two different, brand new sensors, and got the exact same results.

tamorgen · 28th April 2008, 12:45

One other thing, I did read that in CCR you need to set the calibration gas. This does not appear to be the case in semi-closed/open circuit mode, but the fact that my VR3 wants to calibrate like it is in CCR leads me to believe that I may need to set it into CCR mode, set the calibration gas, calibrate it, and then go back into open circuit/semi-closed mode for diving. Does this sound right with anyone?

**PhilSiswick** · 28th April 2008, 12:50

Does this help? http://www.rebreatherworld.com/vr-co...behaviour.html

Looks similar, but I could be wrong. I don't have a VR3, as they confuse me....

tamorgen · 28th April 2008, 12:57

I had come across similar posts, set it to Nx99, set it as the Cal gas, etc, however, setting the Cal gas is only an option under closed circuit. I'm wondering if that is my only option. Hopefully Delta P will respond to my email and tell me what I'm doing wrong, but I've never received a response from their support email. Don't know why. Others say they have been rather prompt and helpfull. Very curious.

Dinspiration · 28th April 2008, 13:44

Hi

For OC/SCR calibration of VR3 the calibration gas is always AIR and can not be changed.

To calibrate the VR3 for SCR you will need to switch the VR3 into OC mode and do the calibration as outlined within the manual with air. The Xdec function has no impact on the calibration at all.
After the calibration in air you can connect the O2 cell holder to your SCR breathing loop, Fill it using the bypass valve and the display should give you the correct reading.

Very often the SCR users did not set and activate the correct gas on the VR3. E.g. If you have a SCR and use a NX 50 with the standard flow rates you will have a NX 45 in your breathing loop. This means you have to set the active gas to a NX 45 and this should be the only active gas on your VR3. Xdec and Xfunc will then calculate the cell reading for you decompression and display it as FO2. If you don’t set the active gas near to the calculated FO2, you can get an “X Check” or “Check FO2” message on the display. To set the gas near your calculated FO2 is more important, if you are playing around with different flow rates. E.g. using a NX 40 with the NX 50 dosage etc.

DINspiration

tamorgen · 28th April 2008, 14:01

Quote: (Originally Posted by Dinspiration)

Hi

For OC/SCR calibration of VR3 the calibration gas is always AIR and can not be changed.

To calibrate the VR3 for SCR you will need to switch the VR3 into OC mode and do the calibration as outlined within the manual with air. The Xdec function has no impact on the calibration at all.
After the calibration in air you can connect the O2 cell holder to your SCR breathing loop, Fill it using the bypass valve and the display should give you the correct reading.

Very often the SCR users did not set and activate the correct gas on the VR3. E.g. If you have a SCR and use a NX 50 with the standard flow rates you will have a NX 45 in your breathing loop. This means you have to set the active gas to a NX 45 and this should be the only active gas on your VR3. Xdec and Xfunc will then calculate the cell reading for you decompression and display it as FO2. If you don’t set the active gas near to the calculated FO2, you can get an “X Check” or “Check FO2” message on the display. To set the gas near your calculated FO2 is more important, if you are playing around with different flow rates. E.g. using a NX 40 with the NX 50 dosage etc.

DINspiration

Hi Dinspiration,
As I mentioned, I did try per the manual. I set the XFunc to Xo2, and began the calibration process. As you said, XDec shouldn't matter, but I attempted both methods.

When I have XFunc set to Xo2, and my VR3 in open circuit mode, I switched the right button to o2, give it a long push, and that brings me to the sensor screen, as expected. I hold down both left and right buttons to go into calibration mode, and it immediate tells me "FLUSH CAL GAS". This is not outlined in the manual, except in CCR mode. I believe if you have bought the CCR pin, the VR3 will only calibrate the o2 sensor in CCR mode. Next it tells me to "EQUALISE", then "STABLE READING?" This is precisely the method for CCR.

The Open circuit method skips both "FLUSH CAL GAS" and "EQUALISE", as illustrated on page 50 & 51 of my manual (2004 V3.0) When I have a stable reading, I should simply be able to give a short push of both switches and it will calibrated to air.

So, if I'm not diving CCR, how do I properly calibrate the unit if it doesn't give me an OC option?

Dinspiration · 28th April 2008, 14:26

Hi

I don't know what you mean with OC option. To use the VR3 with a SCR you will need to switch the VR3 into OC mode.

SCR calibration with VR3:

- Switch the VR3 via Gas Menu into the OC Mode
- Set XFunc to XO2
- Select O2
- Press both buttons to enter calibration mode
- Make sure, that the O2 Cell is in ambient air
- It will ask: Flush Cal Gas - in ambient air you can skip it
- After that it will display: Equalize - in ambient air you can skip it
- Next is: Stable reading. If you have an stable reading press both buttons short to calibrate the VR3 in air. AFTER the calibration the VR3 will display 21.0 % O2 in AIR correctly. Before the calibration it will display whatever is stored in the memory from the last calibration. It can be, that it will display something completly wrong. BUT as soon as you did the calibration it should update the Display with the correct values = 21.0 %.

That's all, what you have to do. This is exaclty how the calibration is done with the actual firmware 2007v.

DINspiration

tamorgen · 28th April 2008, 14:30

Quote: (Originally Posted by Dinspiration)

Hi

I don't know what you mean with OC option. To use the VR3 with a SCR you will need to switch the VR3 into OC mode.

SCR calibration with VR3:

- Switch the VR3 via Gas Menu into the OC Mode
- Set XFunc to XO2
- Select O2
- Press both buttons to enter calibration mode
- Make sure, that the O2 Cell is in ambient air
- It will ask: Flush Cal Gas - in ambient air you can skip it
- After that it will display: Equalize - in ambient air you can skip it
- Next is: Stable reading. If you have an stable reading press both buttons short to calibrate the VR3 in air. AFTER the calibration the VR3 will display 21.0 % O2 in AIR correctly. Before the calibration it will display whatever is stored in the memory from the last calibration. It can be, that it will display something completly wrong. BUT as soon as you did the calibration it should update the Display with the correct values = 21.0 %.

That's all, what you have to do. This is exaclty how the calibration is done with the actual firmware 2007v.

DINspiration

By open circuit option, I mean calibrating the unit as per the open circuit directions on pages 50 & 51 of the manual. Those directions do not say anything about "FLUSH" and "EQUALISE", so I'm a bit perplexed. The method I wrote about above, appears to be the CCR method, which is on pages 52 & 53. It specifically says "Special Procedure for Closed Circuit VR3s". The more I think about it, I think this may be the way I have to do it. I think I have to put it into Closed Circuit to do the calibration, and set a calibration gas. I'm not using it for CCR, but I do have the CCR pin.

I did try the method you wrote (method for CCR VR3s), as I had already said, however it did not give me 21%. The method says "make sure you are in Closed Circuit mode and you see CLOSED CCT at the top of the screen"

After attempting to calibrate off of ambient air, it gave me 32% in air, 50% with my 37% mix (yes, I set me mix when I went to dive it). I don't have the 2007v firmware (I have V3.03aC). So, what could I possibly be doing wrong?

Brainx3 · 28th April 2008, 15:05

Hi,

This might help:

http://www.vr3.co.uk/downloads/manua...s%20manual.pdf

Page 91.

Best Regards. Wael

tamorgen · 28th April 2008, 15:23

Quote: (Originally Posted by Brainx3)

Hi,

This might help:

http://www.vr3.co.uk/downloads/manua...s%20manual.pdf

Page 91.

Best Regards. Wael

Wael,
What are you referring to exactly? Calibration does say "Calibrate as per the analyser instructions." Here is where it is confusing. The "Calibration with analyser (oc VR3) directions should be what I need for SCR, since it's not a closed circuit rebreather. I shouldn't have to flush with O2, and those directions do not tell me to "FLUSH" & "EQUALISE." The "calibration with analyser (cc VR3)" directions do have the "FLUSH" & "EQUALISE" directions, but of course I'm not diving the computer in CCR Mode. Pain in the butt if you ask me.

28th April 2008, 09:04	#1 (permalink)
tamorgen Gadget guru extrordinaire Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Apr 2006 Location: Columbia, MD Posts: 183	Calibrating the VR3 O2 Sensor Hi all, I bought my VR3 last year when I bought my Dolphin to use it to monitor FO2. I have the C9 code (External O2 Sensor), as well as up through C4(CCR & Trimix) I've never had a lot of luck of getting an accurate reading of the FO2, but I went out this weekend for the first dive trip of the season, with brand new sensors, and this has got to take the cake. I hooked up the new sensor, and I went to calibration mode. First off, please note I am using it in semi-closed mode, so Xo2 and XDec are both on. Apparently, it took me a little while to figure out, but this sets the VR3 into calibrating the sensor as per CCR mode. Is this what everyone else has noticed? When I tried calibrating it, I thought it was supposed to calibrate off of air. Well, I tried doing this, and after calibration, it was reading air as 32%. Doesn't quite seem right, does it? I would turn my mix on (38%), and the VR3 would read around 50%. Definately not right. I tried a different, brand new sensor, and I got the same result. I turned off XDec and dove it as table inspiration, and got off the boat. That night, I was reading the manual, and it occured to me to that CCR wants to calibrate via 100% O2 (it tells me to Flush with my calibration mix). So, one of the guys I was diving with had his 13 cu ft O2 bottle for his Optima, so I hooked up the sensor to his bottle, and started the calibration processs all over. The VR3 started calibrating the O2 at 161%, but then I told it to calibrate, it reverted down to 100%, and I thought I was good to go. I stopped flushing, pulled it away (after all calibrated), and it said 21% (air), so I thought I was good to go. Yesterday morning I go out to the boat, and hook up everything, and I think everything is good to go. I plug my VR3 back in to my Dolphin, and it's reading 9% FO2 off of my 37% mix. At this point, I'm like WTF!? So, I again turn off XDec and dive it via the tables. Two things: 1) Can anybody tell me what I'm doing wrong? 2) Can the folks at VR3 kindly write the manual to explain to us using the VR3 in semi-closed mode that you may have to calibrate it via CCR calibration mode? I just about wanted to through the computer over the side this weekend. It was extremely frustrating. Keep in mind that I tried two different, brand new sensors, and got the exact same results.
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28th April 2008, 12:45	#2 (permalink)
tamorgen Gadget guru extrordinaire Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Apr 2006 Location: Columbia, MD Posts: 183	Re: Calibrating the VR3 O2 Sensor One other thing, I did read that in CCR you need to set the calibration gas. This does not appear to be the case in semi-closed/open circuit mode, but the fact that my VR3 wants to calibrate like it is in CCR leads me to believe that I may need to set it into CCR mode, set the calibration gas, calibrate it, and then go back into open circuit/semi-closed mode for diving. Does this sound right with anyone?
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28th April 2008, 12:50	#3 (permalink)
PhilSiswick WSKD 0001 Current Rebreather/s: Evolution Other Rebreather/s: Inspiration Vision Join Date: Apr 2006 Location: Oxford, UK Posts: 880	Re: Calibrating the VR3 O2 Sensor Does this help? http://www.rebreatherworld.com/vr-co...behaviour.html Looks similar, but I could be wrong. I don't have a VR3, as they confuse me.... __________________ Phil No comment on open circuit... it's an evolutionary dead end not really worth discussing here. Dave Sutton, 2007 I have always felt that the dive I am on is not nearly important as the dives I plan to be on the rest of my life. Tom Rose, 2007 www.hugsac.org.uk
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28th April 2008, 12:57	#4 (permalink)
tamorgen Gadget guru extrordinaire Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Apr 2006 Location: Columbia, MD Posts: 183	Re: Calibrating the VR3 O2 Sensor I had come across similar posts, set it to Nx99, set it as the Cal gas, etc, however, setting the Cal gas is only an option under closed circuit. I'm wondering if that is my only option. Hopefully Delta P will respond to my email and tell me what I'm doing wrong, but I've never received a response from their support email. Don't know why. Others say they have been rather prompt and helpfull. Very curious.
(Offline)

28th April 2008, 13:44	#5 (permalink)
Dinspiration Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other CCR Other Rebreather/s: Not Bought Yet Other CCR Join Date: Dec 2005 Location: Switzerland Posts: 195	Re: Calibrating the VR3 O2 Sensor Hi For OC/SCR calibration of VR3 the calibration gas is always AIR and can not be changed. To calibrate the VR3 for SCR you will need to switch the VR3 into OC mode and do the calibration as outlined within the manual with air. The Xdec function has no impact on the calibration at all. After the calibration in air you can connect the O2 cell holder to your SCR breathing loop, Fill it using the bypass valve and the display should give you the correct reading. Very often the SCR users did not set and activate the correct gas on the VR3. E.g. If you have a SCR and use a NX 50 with the standard flow rates you will have a NX 45 in your breathing loop. This means you have to set the active gas to a NX 45 and this should be the only active gas on your VR3. Xdec and Xfunc will then calculate the cell reading for you decompression and display it as FO2. If you don’t set the active gas near to the calculated FO2, you can get an “X Check” or “Check FO2” message on the display. To set the gas near your calculated FO2 is more important, if you are playing around with different flow rates. E.g. using a NX 40 with the NX 50 dosage etc. DINspiration
(Online)

28th April 2008, 14:01	#6 (permalink)
tamorgen Gadget guru extrordinaire Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Apr 2006 Location: Columbia, MD Posts: 183	Re: Calibrating the VR3 O2 Sensor Quote: (Originally Posted by Dinspiration) Hi For OC/SCR calibration of VR3 the calibration gas is always AIR and can not be changed. To calibrate the VR3 for SCR you will need to switch the VR3 into OC mode and do the calibration as outlined within the manual with air. The Xdec function has no impact on the calibration at all. After the calibration in air you can connect the O2 cell holder to your SCR breathing loop, Fill it using the bypass valve and the display should give you the correct reading. Very often the SCR users did not set and activate the correct gas on the VR3. E.g. If you have a SCR and use a NX 50 with the standard flow rates you will have a NX 45 in your breathing loop. This means you have to set the active gas to a NX 45 and this should be the only active gas on your VR3. Xdec and Xfunc will then calculate the cell reading for you decompression and display it as FO2. If you don’t set the active gas near to the calculated FO2, you can get an “X Check” or “Check FO2” message on the display. To set the gas near your calculated FO2 is more important, if you are playing around with different flow rates. E.g. using a NX 40 with the NX 50 dosage etc. DINspiration Hi Dinspiration, As I mentioned, I did try per the manual. I set the XFunc to Xo2, and began the calibration process. As you said, XDec shouldn't matter, but I attempted both methods. When I have XFunc set to Xo2, and my VR3 in open circuit mode, I switched the right button to o2, give it a long push, and that brings me to the sensor screen, as expected. I hold down both left and right buttons to go into calibration mode, and it immediate tells me "FLUSH CAL GAS". This is not outlined in the manual, except in CCR mode. I believe if you have bought the CCR pin, the VR3 will only calibrate the o2 sensor in CCR mode. Next it tells me to "EQUALISE", then "STABLE READING?" This is precisely the method for CCR. The Open circuit method skips both "FLUSH CAL GAS" and "EQUALISE", as illustrated on page 50 & 51 of my manual (2004 V3.0) When I have a stable reading, I should simply be able to give a short push of both switches and it will calibrated to air. So, if I'm not diving CCR, how do I properly calibrate the unit if it doesn't give me an OC option?
(Offline)

28th April 2008, 14:26	#7 (permalink)
Dinspiration Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other CCR Other Rebreather/s: Not Bought Yet Other CCR Join Date: Dec 2005 Location: Switzerland Posts: 195	Re: Calibrating the VR3 O2 Sensor Hi I don't know what you mean with OC option. To use the VR3 with a SCR you will need to switch the VR3 into OC mode. SCR calibration with VR3: - Switch the VR3 via Gas Menu into the OC Mode - Set XFunc to XO2 - Select O2 - Press both buttons to enter calibration mode - Make sure, that the O2 Cell is in ambient air - It will ask: Flush Cal Gas - in ambient air you can skip it - After that it will display: Equalize - in ambient air you can skip it - Next is: Stable reading. If you have an stable reading press both buttons short to calibrate the VR3 in air. AFTER the calibration the VR3 will display 21.0 % O2 in AIR correctly. Before the calibration it will display whatever is stored in the memory from the last calibration. It can be, that it will display something completly wrong. BUT as soon as you did the calibration it should update the Display with the correct values = 21.0 %. That's all, what you have to do. This is exaclty how the calibration is done with the actual firmware 2007v. DINspiration
(Online)

28th April 2008, 14:30	#8 (permalink)
tamorgen Gadget guru extrordinaire Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Apr 2006 Location: Columbia, MD Posts: 183	Re: Calibrating the VR3 O2 Sensor Quote: (Originally Posted by Dinspiration) Hi I don't know what you mean with OC option. To use the VR3 with a SCR you will need to switch the VR3 into OC mode. SCR calibration with VR3: - Switch the VR3 via Gas Menu into the OC Mode - Set XFunc to XO2 - Select O2 - Press both buttons to enter calibration mode - Make sure, that the O2 Cell is in ambient air - It will ask: Flush Cal Gas - in ambient air you can skip it - After that it will display: Equalize - in ambient air you can skip it - Next is: Stable reading. If you have an stable reading press both buttons short to calibrate the VR3 in air. AFTER the calibration the VR3 will display 21.0 % O2 in AIR correctly. Before the calibration it will display whatever is stored in the memory from the last calibration. It can be, that it will display something completly wrong. BUT as soon as you did the calibration it should update the Display with the correct values = 21.0 %. That's all, what you have to do. This is exaclty how the calibration is done with the actual firmware 2007v. DINspiration By open circuit option, I mean calibrating the unit as per the open circuit directions on pages 50 & 51 of the manual. Those directions do not say anything about "FLUSH" and "EQUALISE", so I'm a bit perplexed. The method I wrote about above, appears to be the CCR method, which is on pages 52 & 53. It specifically says "Special Procedure for Closed Circuit VR3s". The more I think about it, I think this may be the way I have to do it. I think I have to put it into Closed Circuit to do the calibration, and set a calibration gas. I'm not using it for CCR, but I do have the CCR pin. I did try the method you wrote (method for CCR VR3s), as I had already said, however it did not give me 21%. The method says "make sure you are in Closed Circuit mode and you see CLOSED CCT at the top of the screen" After attempting to calibrate off of ambient air, it gave me 32% in air, 50% with my 37% mix (yes, I set me mix when I went to dive it). I don't have the 2007v firmware (I have V3.03aC). So, what could I possibly be doing wrong? Last edited by tamorgen : 28th April 2008 at 14:59.
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28th April 2008, 15:05	#9 (permalink)
Brainx3 Temporary Read only mode for site infractions Current Rebreather/s: Inspiration Vision Other Rebreather/s: Inspiration Classic Join Date: Aug 2007 Location: Borås, Sweden Posts: 274	Re: Calibrating the VR3 O2 Sensor Hi, This might help: http://www.vr3.co.uk/downloads/manua...s%20manual.pdf Page 91. Best Regards. Wael
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28th April 2008, 15:23	#10 (permalink)
tamorgen Gadget guru extrordinaire Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Apr 2006 Location: Columbia, MD Posts: 183	Re: Calibrating the VR3 O2 Sensor Quote: (Originally Posted by Brainx3) Hi, This might help: http://www.vr3.co.uk/downloads/manua...s%20manual.pdf Page 91. Best Regards. Wael Wael, What are you referring to exactly? Calibration does say "Calibrate as per the analyser instructions." Here is where it is confusing. The "Calibration with analyser (oc VR3) directions should be what I need for SCR, since it's not a closed circuit rebreather. I shouldn't have to flush with O2, and those directions do not tell me to "FLUSH" & "EQUALISE." The "calibration with analyser (cc VR3)" directions do have the "FLUSH" & "EQUALISE" directions, but of course I'm not diving the computer in CCR Mode. Pain in the butt if you ask me.
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