Poseidon M28 Open Circuit

[jagould2000]

Does anyone know if the Poseidon M28 can be used in its OC mode with an HP sensor? The Dive-by-Wire stuff isn’t very well documented outside of the SE7EV rebreather. They sell a CAN cable / HP sensor banjo, which is used as the Dil sensor on the rebreather.

Has anyone used that sensor for tank pressure in OC mode without a rebreather? Can you connect multiple sensors on the CAN bus for multiple tanks? (OC mode supports 8).

Seems like a great substitute for HP hoses or wireless transmitters for an air integrated computer.

Thanks!

 

[RainPilot]

On the rebreather, the HP banjo transmits the pressure data to the emodule, which in turn relays that to the M28 via the cable. How would you connect the HP hose to the M28 without a module in-between? The CAN cable banjo and the M28 cable have the same ends so would not connect to each other. I am also not sure I would like a direct connection from my tank to my arm computer, that would be a good way for me to break my arm when I forgot and took off the tank before I removed the computer.

Sadly there is no current way to get wireless AI to the M28, nor are they currently planning to add that feature.

 

[jagould2000]

Thanks @RainPilot. The good folks at Dive Gear Express confirmed the same (replying to emails at 4:30am on a weekend!).

Strange that Poseidon missed this opportunity. Looks like all the hardware is there, the banjo just isn’t writing that data to the bus in a way that the m28 can get it without the emodule.

Guess I’ll have to wait until I work my way up to a SE7EN. Just was thinking while I was buying a new OC computer, I could get $2k closer to a rebreather with the purchase. Shearwater Perdix it is - though don’t love wireless transmitter idea.

 

[tbone1004]

Thanks @RainPilot. The good folks at Dive Gear Express confirmed the same (replying to emails at 4:30am on a weekend!).

Strange that Poseidon missed this opportunity. Looks like all the hardware is there, the banjo just isn’t writing that data to the bus in a way that the m28 can get it without the emodule.

Guess I’ll have to wait until I work my way up to a SE7EN. Just was thinking while I was buying a new OC computer, I could get $2k closer to a rebreather with the purchase. Shearwater Perdix it is - though don’t love wireless transmitter idea.

Flawed logic a bit there as I don't think you can buy the se7en without the M28 as a controller and certainly not for retail price on the M28 cheaper. Best off to get it with the unit.

Wireless transmission of tank pressures is quite reliable with the Shearwater so long as the battery is good it will receive as there is no active pairing. One-way transmission like an FM radio.

 

[jagould2000]

It would have been a second m28 on a CPOD. I understand primary comes with the unit.

 

[RainPilot]

You can buy the Poseidon with a paddle, still, though you'd be running analog cells till you got an M28 to handle the solid state. That being said, with 2 solid state sensors the need for a 3rd cell reader is becoming a lot less of an issue. I have not yet seen ANY difference between my sensors to the second decimal PPO2. Those things are rock solid, and I also dont advocate staying on the loop if the main electronics are dead but YMMV.
I run a Shearwater as a backup DC in set point mode so you wont be buying unnecessarily.

Before you pull the trigger on a Se7en, drop me a DM or email brendonatpranadivedotcom and I'll talk you through the options to bring that initial sticker price down.