Quote: (Originally Posted by
rdmmdr)
the whole talk about protecting the boards during a flood seems mute because after a flood only an idiot would try to wash the board and reuse.
We are talking about a handset flood destroying not just the handset but the entire system. If the handset floods, and it is disconnectable as it is in the Open Revolution designs, then it is easy to plug in another one. One does not have to think about whether the sensors in the base unit are wrecked.
Quote: (Originally Posted by
rdmmdr)
i really like the idea of the flow control valve due to fact that loss of power/ control gives a fixed oraface, but how are handling a runaway of the valve controller. it seems that you have added multiple modes of failure here not subtracted them and increased the complexity of the part way beyond what it needs to be.
The complexity is inside two chips: an FPGA and a microcontroller. The engine management unit on your car is far more complex. The MTBF is published and the MTBCF, along with their calculation.
Please be specific when you refer to vague reliability issues.
Quote: (Originally Posted by
rdmmdr)
the basic problem with the solenoids is corrosion of the plunger. a redesign of the plunger seems to be the best solution to this issue and the simplest. life threating issue with the solenoids are stuck open or failure to open, failure to open is a problem that you have time to deal with. stuck open, while a more critical problem time wise, can be mediate with a properly design flow limiter,a pneumatic fuse and proper training.
A problem with solenoids is corrosion, but a bigger one is intermediate pressure changes. For solenoids, stuck shut or open is a dangerous situation. Solenoids cannot be fail safe, ever. You suggest designing a safer one: please publish it, as we have published ours.
Quote: (Originally Posted by
rdmmdr)
you are placing the batteries in the loop, a battery short in a high humidity high o2 environment is a failure i would not be comfortable with, how are you dealing with this issue.
There are NO BATTERIES IN THE LOOP. They are outside the loop, outside the rebreather even, in a 1 ATM environment.
Quote: (Originally Posted by
rdmmdr)
encapsulating, you say that this causes more problems then it solves. i agree that there are problems with encapsulating the electronics, thermal stress and mechanical stress imposed upon the board, but don,t the benefits outweigh the a limited number of damaged boards during manufacture. and since the industry has been doing it for years these problems have been solved.
Look up the "Cracked Handset" thread. The potting problem has not been solved. It creates a lot of failure points. I have had lots of clients try potting over the years, against my advice, and every time it caused problems.
Quote: (Originally Posted by
rdmmdr)
having talked to both ai and teledyne about the molex connector, what shitty idea those where for a rebreather, any decent molded connector will give you better results. i personally am using the the r-17d for that reason and have asked both manufacturers to look in to gold plating their connectors.
The jack socket is also unsuitable. Try an SMB socket.
Quote: (Originally Posted by
rdmmdr)
i will take the risk of corrosion on the cell side rather then having to replace the harness. i question the protection of the input Chanel does not the load resister handle this and if the load resister is bad then is not the board already shot.
The load resistor is inside the O2 sensor, for Teledyne and AII.
Quote: (Originally Posted by
rdmmdr)
since you have installed a pressure sensor in the unit i assume that you will be including some deco software, what will be the mandatory re-cal requirement for the sensor. since even using two sensors here will not give you redundancy since both sensors are subjected to the same mechanical and thermal stresses. we annually service our regs but how many throw their deco computer in the pot to check the sensor.
rick
No need to assume. Just download the verification environment and try it. It has deco algorithms.
There are multiple pressure sensors (3), in three different places. Which is why we put so much effort into reducing their cost. We have also tested the sensors in pure helium for a month, at 1400msw, to check for the creep. We do not have to recalibrate for life, but we do detect their failure.
I have all the time in the world for those wanting to explore, to challenge, to learn, to help or to point out a better way. However with you I am wary, because after pointing out the ESD issue you still seem unaware of, rather than show me the error of my reasoning, you threw a tantrum and started an F word thread just to slag me off. I am very wary of answering that sort of unstable person. It is clear by your post here that you did not even bother to look at all at the stuff we published before doing so.
We look forward to seeing how well your improved solenoid works.
Before you embark on, it is worth buying everyone elses and testing them to find what the problems are.
Incidentally, we are still waiting to see the $100 handset you promised your engineers could design in a day.
Alex