Question Using a tank transmitter with doubles (twinset)

[Original_bardo]

For those of you using a transmitter for you dive computer with doubles, how are you configuring the settings?

Here's my case:

Garmin Dive Computer
T1 Transmitter
Nautec Manifold
Twin LP85

The SPG would go on the left post, while the transmitter is on the right. During normal operation the SPG and transmitter should be reading the pressure for both tanks. In the case of the transmitter, I'd assume its setup as the volume of two LP85s. In the event of a failure on the left post 1st stage or during valve drills, the isolator would be closed. This would then throw off the transmitter calculations because it would not know that you just lost half your volume of gas. So in this situation would you do a gas switch in your computer to a pre programmed "back up gas" that's setup for the single LP85?

Does that make sense or am I over complicating it? I know if you have a failure and need to isolate your dive is done. However, on the ascent without a transmitter you have no way of telling your remaining gas. A lot of people don't like the transmitters but I think they add a lost of information on SAC rate and gas consumption in general.

Thanks,
bardo

 

[Tracy]

I run mine on my left post to replace the pressure gauge. I don't set anything up, it is just a pressure gauge.

 

[formernuke]

Just use the pressure and it's now attached to a single tank.

As for calculations that's the last thing I'm worried about that situation.

 

[Original_bardo]

Good points guys, I'm over thinking it. Thanks

 

[broncobowsher]

Yep, overthinking it. Failure means you are done, go back. Proper planning and you don't need a gauge at all as you already planned your gas consumption. So you will have a wacky data log, oh well.

But split gauge and transmitter on separate 1st stages will allow cross checking to verify the manifold is open.

 

[Original_bardo]

Yep, overthinking it. Failure means you are done, go back. Proper planning and you don't need a gauge at all as you already planned your gas consumption. So you will have a wacky data log, oh well.

But split gauge and transmitter on separate 1st stages will allow cross checking to verify the manifold is open.

Thanks

 

[ChrisMBC]

FWIW, I do exactly what you listed (T1 transmitter on right post, SPG on left). It does send the computer a little crazy when I do a valve drill and shut down my right post, it doesn’t significantly affect the overall average consumption for the dive).

For example, here’s a dive with a couple of right-post shutdowns and bunch of S-drills that elevated SAC. Doing drills will mess with the minute-by-minute stats, I’d either deal with it or not run the transmitter!

 

[Angelo Farina]

For those of you using a transmitter for you dive computer with doubles, how are you configuring the settings?

Here's my case:

Garmin Dive Computer
T1 Transmitter
Nautec Manifold
Twin LP85

The SPG would go on the left post, while the transmitter is on the right. During normal operation the SPG and transmitter should be reading the pressure for both tanks. In the case of the transmitter, I'd assume its setup as the volume of two LP85s. In the event of a failure on the left post 1st stage or during valve drills, the isolator would be closed. This would then throw off the transmitter calculations because it would not know that you just lost half your volume of gas. So in this situation would you do a gas switch in your computer to a pre programmed "back up gas" that's setup for the single LP85?

Does that make sense or am I over complicating it? I know if you have a failure and need to isolate your dive is done. However, on the ascent without a transmitter you have no way of telling your remaining gas. A lot of people don't like the transmitters but I think they add a lost of information on SAC rate and gas consumption in general.

Thanks,
bardo

In my experience closing the isolator is a very extreme case, which does not happens frequently, The most common case is that one of the two regs free flows, so you close ITS valve, The insulation remain open and you stll have access to all your air from the other other reg...
In reality, insulation manifolds are a recent innovation: for decades twin sets had just twin valves, and the manifold was NOT capable of insulating one tank from the other.
The insulation manifold wa introduced for extreme tech diving, and is substantially unneeded for most twin-tank diving. So you are worrying about a case which is not really relevant...

 

[tursiops]

during valve drills, the isolator would be closed. This would then throw off the transmitter calculations because it would not know that you just lost half your volume of gas.

The transmitter and computer never know the tank volume. All calculations are made on the rate of pressure drop.

 

[Original_bardo]

The transmitter and computer never know the tank volume. All calculations are made on the rate of pressure drop.

My transmitter calculates based off volume. Before each dive you enter the type of tank you’ll be diving with.