Best rEvo sensor configuration?

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stuartv

Seeking the Light
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I just bought a used rEvo. It has a DiveCAN Predator controller (w/RMS, if that matters), a Predator Fischer cable monitor, and a Shearwater HUD.

The sensor tray will hold 5 sensors.

A person at Add Helium said their normal configuration for the rEvo is 4 sensors. 3 to the controller and 1 to a monitor. That seems odd, to me. I would have expected 3 to the controller and 1 to each of the Dreams, in a base eCCR config. Maybe I misunderstood what I was being told, but I am sure she said they only set them up with 4 sensors.

The instructor I will be doing my training with prefers to use 5 sensors. He said I can use 4 or 5, whichever I choose.

I expect that I will start by using 5 and setting them up the way my rEvo instructor does his. But, I would like to know the thoughts of some of the experienced rEvo divers on here regarding how I should set it up.

3 sensors to the controller is a given.

Should I run 3 sensors to the Predator monitor, so that 1 is in common with the controller?

What sensors should I run to the HUD? It will also monitor 3. Should it monitor the same 3 as one of the Predators? A unique combo of 3, that is different than either of the Predators?

Or should I run 3 to the controller and the other 2 to both the Predator monitor and the HUD?

Or only use 4 sensors?

Thanks for any insights!
 
Hi stuartv,

I have been diving a rEvo for over 5 years, and run 5 sensors, 3 on the controller, and 2 on the rEvo dream/hud which in your case would be the Fischer predator. When I first started on the rEvo I started with 4 sensors (3 on the controller and 1 on the dream) then after 6 months added the 5th sensor as recommended by rEvo, this is probably the process that Add Heium would follow. I replace a sensor every 6 months, rotating them through my unit from position 1 to 5 in the tray, that newest sensor in position 1 oldest in 5. I suggest you read understanding oxygen sensors by Paul Raymakers (the maker of the rEvo) you can down loaded here Downloads

Enjoy your time on the rEvo, they are a fantastic unit despite what some on here may say.
 
I don’t dive a Revo...so take this with a grain of salt.

I have 4 sensors in my optima. 3 to the controller, 3 to the hud. Sensors 1 and 2 are shared, sensor 3 goes to the controller, sensor 4 to the hud.

This makes sense since 1 and 2 should match on the controller and hud, but the third sensor for either are independent. This way you have more info to use to your advantage if a cell is acting funky during a dive.
 
You are using 2 Predator, one as controller, one driving the HUD and as well 2 dreams fixed?

First, there is something too much. I would either take the dreams off entirely and run them 3 on controller and 2 on HUD or alternatively remove the second predator and replace the HUD w. 2 Dream HUD.

Perhaps I didnt get it right anyways...

However, you rightly said the 3 cells for the controller is a given, now there are different philosophies. From my engineering and rEvo diving experience I'd avoid cross-wiring at all cost. Meaning every Computer (no matter if Dream or Petrel or Predator) has no galvanic connection to either of the others.

I am diving with 2 dreams with each one cell and 3 on the controller for the reason of having direct comparism of the 2 dreams working at equal pace, meaning I'd be voting them out manually if one differs and then only focus on the Computer.

In your case this means same as you said if using 2 Predators. 3 cells on controller, 2 on the HUD Predator.
 
As tbone said, I have no Dreams (poor me!). Only the Predator controller, Predator monitor (Fischer cable), and Shearwater HUD.

From my engineering and rEvo diving experience I'd avoid cross-wiring at all cost. Meaning every Computer (no matter if Dream or Petrel or Predator) has no galvanic connection to either of the others.

Can you elaborate on this a bit? Why do you feel it is so important to not have any sensor shared by more than one device? From what I can tell, using splitters and having the same sensor connected to 2 devices seems to be common and a well-accepted practice.
 
@stuartv splitters usually cause interference and are prone to signal degradation. It's why the old Meg has an isolator board. @DA Aquamaster had enough problems with the splitters for his HUD that he actually took it off.

I don't know how the wiring is done in the DiveCAN Revo though. If it's split before the ADC I'd be wary. If the DiveCAN is sending out the analog voltage then it should be less bad.
If the HUD is DiveCAN, I would abandon the fischer cable Predator and just use the 3 cells going to the O2 board. You are adding tons of risk and failure points using any wire splitters in there and it negates any potential benefit of the multiple cells
 
I replace a sensor every 6 months, rotating them through my unit from position 1 to 5 in the tray, that newest sensor in position 1 oldest in 5.
Why the extra trouble of rotating the sensors? You miss the possibility to monitor mV changes over time on each sensor, by swapping which digitizer it is read from...
And 6 months might be a tad long... That's pushing over two years on the oldest sensor. I switched to 4 months (and monitor the mV of each cell, corrected for ambient pressure).
 
Why the extra trouble of rotating the sensors?
My preference is to keep my three newest, and most reliable sensors on the predator controller and the two oldest sensors on the dream which is the back up.
I can still track mV reading for all sensors over their life and have been doing this. 6 months is the rEvo recommendation and have noticed very few issues. On one or two occasions one of the two older sensors have failed before being rotated out and I have disabled this sensor until the new one is added.
 

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