Hammerhead's Delrin vs Vision Electronics

UKSteve · 26th August 2008, 09:55

Quote: (Originally Posted by jradomski)

once you go with a microprocessor controlled switching system all sorts of failure can pop in.. Its not limited to the vision.. for every failure there are generally ways to detect and correct them but the electronics start to get very complex... from what I saw on a set of electronics I took apart a while back the vision electronics are pretty simple and appears to be highly dependent on doing everything by the cpus..

Micro controllers are subject to alot of different types of RANDOM failures, some are more predictable than others.. The potential consequences all depend on where and when the failure ocurs.. lets use a general cpu failure..

The cpu locks up.. this is usually detectable by watchdog timers, but what if the clock supplying the wd fails, well then the watchdog doesnt work.. if a crystal failure caused the cpu to lock (and its also supplied the wd), and the mechanism to detect the lock up failed then you have an unrecoverable failure.. depending on how this fails the consequences can be nothing to major.. once you get cpus controlling power sources a trouble like this can have serious implications.. Real power control generally has to be done on timescales that are generally not attainable with microcontrollers.

reliable systems need very complex failure analysis, each subsystem could take months to analyze, then you need an overall failure analysis.. This is the reason why reliable systems usually implement different ways to accomplish the same goal within the same system so that its unlikely that a common failure can happen..

Interesting stuff...thanks for taking time to elaborate...and obviously thought provoking as a Vision user.

I have seen one occurrence of lock up of a Vision..actually on my Mod 1 course. The handset numbers froze..apparently due to a loss of comms between head and handset - yet actually the controllers were still working and maintaining ppO2 on the unit...we realised that when we got above 4m and the unit kept injecting O2 to attain 1.3 ppO2.

If I understand the Vision architecture correctly, however, there are two separate processors in the head of the unit each performing power management independently. Doesnt that provide sufficient protection from the kind of failure you describe?

Many thanks

Steve

***jradomski*** · 26th August 2008, 11:32

Quote: (Originally Posted by UKSteve)

If I understand the Vision architecture correctly, however, there are two separate processors in the head of the unit each performing power management independently. Doesnt that provide sufficient protection from the kind of failure you describe?

Many thanks

Steve

It all depends... sometimes yes, sometimes now.. Thats why failure analysis is so critical.. the vision systems have the ability to decide who gets power, that in itself lies the problem.. thats why shared systems are generally frowned upon.. if you look at any mission critical power systems they always have some sytem that is paralleled, not a system that can be deprived from anoter system.. Thats why I stated that you either want independent power systems with possibley a backup for each, or independet power systems with a shared isolated bacup.. This way there is no way for a failed subsystem to deprive power from a working system.

The vision architecture is basically 2 controllers with a shared display and shared power system.. Losing the display doesnt interfer with the controllers, its just an IO failure... Its not the type of lockup I am talkig about... lsing the handset is akin to loosing your keybpard and monitor, any program running is still running, but once an action is needed nothing can be entered..

I like the ideas put together in the vision and really like the handset, but comming from the background that I have I really can't have confidence in the power system used by the vision. The only way I would have confidence is adding an independent monitoring system with 3 sensors..

UKSteve · 26th August 2008, 12:36

Joe,

Cheers....as ever .more food for thought. I wonder how the architecture / power management compares with power supplies for other current ECCRs?

Steve

chrismc · 26th August 2008, 12:40

The best way to look at the failures is look at what would happen in a specfiic siutaution and what would be the consequences.

For example the wrist computer is independant to the controllers, but it does set the set point etc. and you cant see what its set to without it. Also consider the HUD doesnt tell you what the PPo2 is, just that its on/off target. So if you lose connection/damage etc. then how do you know the controllers are mainitaing the right PP02? imaigne doing your deco on 0.7?

The controllers are identical, and both have access to the power supply. Very good if the controllers are perfect and the user doesnt change the batteries often. However if one controller goes wrong it can drain both batteries.

Batteries and controllers are held in the same location, 100% humidity for which they werent designed. Would one fail and not the other? depends on the fault.

To many designs are to smart. They have considered what the user could do wrong, and how they can correct this, not considering how they could go wrong.

I'm a big fan of completly redudany systems, so in the event of a failure, the second system is COMPLETLY independant, where possible.

IMHO the hammerhead does provide this, there is no way for an error on one system to affect the other. Controller 1 simply cannot drain controller 2's battery etc.

I bought my classic second hand, and unknown to me it had been flooded and cleaned up. The battery box had got wet internally, there was no way to know this. 6 months later it rusted through and both power supplies went off on the same dive. I did have a 4th cell with a VR3, which obviosuly wanst affected.

Mark Chase · 26th August 2008, 13:27

Quote: (Originally Posted by LoneStarDiver)

Hello!

I am a U.S. based diver with a five-year old Buddy Inspiration rebreather (aka Classic). Need to get a new electronic / decompression system and thinking about either Hammerhead's Delrin handsets and Silent Diving's Vision Electronics. Of course, cost is a consideration and given the pricing of the Vision, getting a whole new Inspiration rebreather plus the electronics almost makes sense (almost).

But it would great get to some opinions on operational characteristics (ease of use, understandability, ruggedness, reliability, etc.) of these two systems. Thank you!

Neither,

Have a look at this:

Deep Pursuit rebreather controller

I wouldent go for a Vision due to the single wrist unit being the only option. The Hammerhead is a stunning bit of kit, but the outragious problems they have with output tollerance on batterys make it very very anoying to use.

The Support and service that I have had from Shearwater and their excelent product would have me going this rout. I am very impressed with the design detail and the redundancy of a very simple second passive display and HUD is very much in line with my thaughts on redundancy.

ATB

Mark

Blomman · 26th August 2008, 23:12

Quote: (Originally Posted by Mark Chase)

Neither,

Have a look at this:

Deep Pursuit rebreather controller

Isn't the D.P. still under development and can't be bought yet?

// Blomman

MarkZ · 27th August 2008, 06:18

Quote: (Originally Posted by jradomski)

MY vote is for the HH electronics..

Certainly have a right to your opinion. Not a bad choice

I despise the power system in the vision electronics and to me a single handset is a true lack of redundancy.. I have hours on both, and decided long ago not to buy a set of vision electronics.. I prefer the classic electronics over the vision electronics.

To be honest I had my doubts also but after lengthy conversations with those who know the unit best I am confident that there is redundancy in the system. I love the classic electronics also but let's face it they are not as good as the Vision despite mental blocks with the single handset and HUD. And lets face it the HH handsets connects to the cells via a Y connection to the sensors which opens a potential for failures.

I would have no trouble using a vision for reasonable length dives, but would never consider using one on a expedition type dive..

Frankly and with all due respect this constant babble about AP products not being "expedition" quality is laughable. The were used on the Britannica, Doria, and countless other expeditions, not to mention cave dives too numerous to list. The series is still the most widely purchased and dived units on the market. Please share what expeditions you are doing that they would not be suited for.

at this point I have several sets of HH electonics.. I have them on 2 inspirations and I have the HH rebreather..

And you also have a relationship there that goes far beyond neutral.

I don't think the temp stick is any great thing (BTW the US navy which intially did the research on this type of sensing along time ago, determined it was unreliable and the patent was assumed by one of the researchers) and all my logging is done through a cochran computer which beats any other logging system hands down..

Nobody claims the stick is more then an additional tool to monitor. Vast majority of the users seem to be very happy with it. I do not see any other company showing up to bat with anything better. Doesn't Alex have a similar setup on his rebreather to beat all rebreather's that costs 100K and nobody can buy? Funny to hear you tout redundancy yet you still have to carry a cochran computer to log dives. I assume you find the cochran is more reliable then the Explorers that you also push?

right now about half of the active ANDI ITDs primarily use HH based rigs for their own diving..

And how many would that be?

The initial poster will make his own decision and hopefully he will be happy with it. I have used a HH briefly and frankly I didn't have any problems with it and it had a lot of features that I liked. I have friends that dive the HH rebreather and they are quite happy with it. I do not have a personal relationship with Kevin but I have spoken with him at length on several occasions and I am of the opinion that he is a top notch person. Can't find a nicer guy or a more reasonable person. I am of the same opinion of those I have met from AP and SDS.

I do have a bit of an issue by the bashing that AP or anybody else for that matter gets on this site by individuals who have conflicting commerical interests portraying themselves and neutral parties.

***jradomski*** · 27th August 2008, 07:09

Mark,
I teach and own multiple rebreathers, so my comments are based on my preference.. I couldn't care less if a person purchased a rEvo, HH or inspiration if it was right for their diving.

When I do rebreather demos, I always bring the above rigs and some others that I don't teach.. Everyone has a favorite and thats what they will suggest first and thats what I do.. In the next 2 months I have several rEvos that I have sold and have to train people on.. For them it was the right choice.. I also sell KISS rebreathers and still do some training on Inspirations.. I'dsay thats pretty neutral and not locked into one commercial interest..

I like the Explorer for its profiles but frankly the 15 second logging doesnt cut it.. The cochran logs every second.. mine has 1450 hours of logging.. and if I needed it I have another computer.. Its the best for the job so I use it..

DIves like the doria, arent really expedition level dives in my book.. Typical run times are less than 90 minutes.. The britanic dives are more in what I consider expedition level.. I do alot of dives with 4+ hour run times, in that case I want a system I can stay on the loop under anything but a failure of loop integrerity.

Just because dives were done on it doesnt mean it was suitable.. People have done dives on the doria with a SINGLE 72... Does that mean it was safe or smart.

I have a specific confort level in my equiptment that I want.. I have that level with teh classic electronics, I dont have that with the vision..

Mark Chase · 27th August 2008, 07:51

Quote: (Originally Posted by Blomman)

Isn't the D.P. still under development and can't be bought yet?

// Blomman

No its available now.

ATB

Mark

scunick · 27th August 2008, 08:17

Just moved to a HH CCR and it is just SO much more robust. I like the electronics and the simplicity of the display and have to date not missed anything I had on the vision handset and really enjoy the redundant handsets.

IMHO the HH is a robust independant solution to the problem.

Later

Nick

26th August 2008, 09:55	#11 (permalink)
UKSteve Steve Collard Current Rebreather/s: Inspiration Vision Other Rebreather/s: Join Date: Jul 2005 Location: Weymouth, UK Posts: 601	Re: Hammerhead's Delrin vs Vision Electronics Quote: (Originally Posted by jradomski) once you go with a microprocessor controlled switching system all sorts of failure can pop in.. Its not limited to the vision.. for every failure there are generally ways to detect and correct them but the electronics start to get very complex... from what I saw on a set of electronics I took apart a while back the vision electronics are pretty simple and appears to be highly dependent on doing everything by the cpus.. Micro controllers are subject to alot of different types of RANDOM failures, some are more predictable than others.. The potential consequences all depend on where and when the failure ocurs.. lets use a general cpu failure.. The cpu locks up.. this is usually detectable by watchdog timers, but what if the clock supplying the wd fails, well then the watchdog doesnt work.. if a crystal failure caused the cpu to lock (and its also supplied the wd), and the mechanism to detect the lock up failed then you have an unrecoverable failure.. depending on how this fails the consequences can be nothing to major.. once you get cpus controlling power sources a trouble like this can have serious implications.. Real power control generally has to be done on timescales that are generally not attainable with microcontrollers. reliable systems need very complex failure analysis, each subsystem could take months to analyze, then you need an overall failure analysis.. This is the reason why reliable systems usually implement different ways to accomplish the same goal within the same system so that its unlikely that a common failure can happen.. Interesting stuff...thanks for taking time to elaborate...and obviously thought provoking as a Vision user. I have seen one occurrence of lock up of a Vision..actually on my Mod 1 course. The handset numbers froze..apparently due to a loss of comms between head and handset - yet actually the controllers were still working and maintaining ppO2 on the unit...we realised that when we got above 4m and the unit kept injecting O2 to attain 1.3 ppO2. If I understand the Vision architecture correctly, however, there are two separate processors in the head of the unit each performing power management independently. Doesnt that provide sufficient protection from the kind of failure you describe? Many thanks Steve
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26th August 2008, 11:32	#12 (permalink)
*jradomski* Moderator Current Rebreather/s: Inspiration Classic Sport Kiss Optima rEvo Other CCR Other Rebreather/s: Inspiration Vision Evolution Megalodon Classic Kiss rEvo Other CCR Join Date: Mar 2005 Location: "Da" Bronx Posts: 3,115	Re: Hammerhead's Delrin vs Vision Electronics Quote: (Originally Posted by UKSteve) If I understand the Vision architecture correctly, however, there are two separate processors in the head of the unit each performing power management independently. Doesnt that provide sufficient protection from the kind of failure you describe? Many thanks Steve It all depends... sometimes yes, sometimes now.. Thats why failure analysis is so critical.. the vision systems have the ability to decide who gets power, that in itself lies the problem.. thats why shared systems are generally frowned upon.. if you look at any mission critical power systems they always have some sytem that is paralleled, not a system that can be deprived from anoter system.. Thats why I stated that you either want independent power systems with possibley a backup for each, or independet power systems with a shared isolated bacup.. This way there is no way for a failed subsystem to deprive power from a working system. The vision architecture is basically 2 controllers with a shared display and shared power system.. Losing the display doesnt interfer with the controllers, its just an IO failure... Its not the type of lockup I am talkig about... lsing the handset is akin to loosing your keybpard and monitor, any program running is still running, but once an action is needed nothing can be entered.. I like the ideas put together in the vision and really like the handset, but comming from the background that I have I really can't have confidence in the power system used by the vision. The only way I would have confidence is adding an independent monitoring system with 3 sensors.. __________________ Joe Radomski CCR Trimix Instructor Trainer ANDI Instructor Trainer Director #10 All posts are personal opinions and DO NOT reflect any affiliated agency unless specifically stated.
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26th August 2008, 12:36	#13 (permalink)
UKSteve Steve Collard Current Rebreather/s: Inspiration Vision Other Rebreather/s: Join Date: Jul 2005 Location: Weymouth, UK Posts: 601	Re: Hammerhead's Delrin vs Vision Electronics Joe, Cheers....as ever .more food for thought. I wonder how the architecture / power management compares with power supplies for other current ECCRs? Steve
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26th August 2008, 12:40	#14 (permalink)
chrismc RBW Member Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Sep 2005 Location: North west, uk Posts: 62	Re: Hammerhead's Delrin vs Vision Electronics The best way to look at the failures is look at what would happen in a specfiic siutaution and what would be the consequences. For example the wrist computer is independant to the controllers, but it does set the set point etc. and you cant see what its set to without it. Also consider the HUD doesnt tell you what the PPo2 is, just that its on/off target. So if you lose connection/damage etc. then how do you know the controllers are mainitaing the right PP02? imaigne doing your deco on 0.7? The controllers are identical, and both have access to the power supply. Very good if the controllers are perfect and the user doesnt change the batteries often. However if one controller goes wrong it can drain both batteries. Batteries and controllers are held in the same location, 100% humidity for which they werent designed. Would one fail and not the other? depends on the fault. To many designs are to smart. They have considered what the user could do wrong, and how they can correct this, not considering how they could go wrong. I'm a big fan of completly redudany systems, so in the event of a failure, the second system is COMPLETLY independant, where possible. IMHO the hammerhead does provide this, there is no way for an error on one system to affect the other. Controller 1 simply cannot drain controller 2's battery etc. I bought my classic second hand, and unknown to me it had been flooded and cleaned up. The battery box had got wet internally, there was no way to know this. 6 months later it rusted through and both power supplies went off on the same dive. I did have a 4th cell with a VR3, which obviosuly wanst affected.
(Offline)

26th August 2008, 13:27	#15 (permalink)
Mark Chase RBW Member Current Rebreather/s: Classic Kiss Other Rebreather/s: Inspiration Classic Join Date: Jan 2005 Location: Kent Posts: 2,867	Re: Hammerhead's Delrin vs Vision Electronics Quote: (Originally Posted by LoneStarDiver) Hello! I am a U.S. based diver with a five-year old Buddy Inspiration rebreather (aka Classic). Need to get a new electronic / decompression system and thinking about either Hammerhead's Delrin handsets and Silent Diving's Vision Electronics. Of course, cost is a consideration and given the pricing of the Vision, getting a whole new Inspiration rebreather plus the electronics almost makes sense (almost). But it would great get to some opinions on operational characteristics (ease of use, understandability, ruggedness, reliability, etc.) of these two systems. Thank you! Neither, Have a look at this: Deep Pursuit rebreather controller I wouldent go for a Vision due to the single wrist unit being the only option. The Hammerhead is a stunning bit of kit, but the outragious problems they have with output tollerance on batterys make it very very anoying to use. The Support and service that I have had from Shearwater and their excelent product would have me going this rout. I am very impressed with the design detail and the redundancy of a very simple second passive display and HUD is very much in line with my thaughts on redundancy. ATB Mark __________________ See my "Doing It Chasey" video where I'm locked into a padded room, naked, with two ball bearings and within an Hour, I manage to lose one and break the other!!! Kevin Juergensen 16/11/08 [/quote]
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26th August 2008, 23:12	#16 (permalink)
Blomman Helium is addictive! Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Jan 2006 Location: Sweden Posts: 153	Re: Hammerhead's Delrin vs Vision Electronics Quote: (Originally Posted by Mark Chase) Neither, Have a look at this: Deep Pursuit rebreather controller Isn't the D.P. still under development and can't be bought yet? // Blomman
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27th August 2008, 06:18	#17 (permalink)
MarkZ RBW Member Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Jan 2006 Location: PA USA Posts: 106	Re: Hammerhead's Delrin vs Vision Electronics Quote: (Originally Posted by jradomski) MY vote is for the HH electronics.. Certainly have a right to your opinion. Not a bad choice I despise the power system in the vision electronics and to me a single handset is a true lack of redundancy.. I have hours on both, and decided long ago not to buy a set of vision electronics.. I prefer the classic electronics over the vision electronics. To be honest I had my doubts also but after lengthy conversations with those who know the unit best I am confident that there is redundancy in the system. I love the classic electronics also but let's face it they are not as good as the Vision despite mental blocks with the single handset and HUD. And lets face it the HH handsets connects to the cells via a Y connection to the sensors which opens a potential for failures. I would have no trouble using a vision for reasonable length dives, but would never consider using one on a expedition type dive.. Frankly and with all due respect this constant babble about AP products not being "expedition" quality is laughable. The were used on the Britannica, Doria, and countless other expeditions, not to mention cave dives too numerous to list. The series is still the most widely purchased and dived units on the market. Please share what expeditions you are doing that they would not be suited for. at this point I have several sets of HH electonics.. I have them on 2 inspirations and I have the HH rebreather.. And you also have a relationship there that goes far beyond neutral. I don't think the temp stick is any great thing (BTW the US navy which intially did the research on this type of sensing along time ago, determined it was unreliable and the patent was assumed by one of the researchers) and all my logging is done through a cochran computer which beats any other logging system hands down.. Nobody claims the stick is more then an additional tool to monitor. Vast majority of the users seem to be very happy with it. I do not see any other company showing up to bat with anything better. Doesn't Alex have a similar setup on his rebreather to beat all rebreather's that costs 100K and nobody can buy? Funny to hear you tout redundancy yet you still have to carry a cochran computer to log dives. I assume you find the cochran is more reliable then the Explorers that you also push? right now about half of the active ANDI ITDs primarily use HH based rigs for their own diving.. And how many would that be? The initial poster will make his own decision and hopefully he will be happy with it. I have used a HH briefly and frankly I didn't have any problems with it and it had a lot of features that I liked. I have friends that dive the HH rebreather and they are quite happy with it. I do not have a personal relationship with Kevin but I have spoken with him at length on several occasions and I am of the opinion that he is a top notch person. Can't find a nicer guy or a more reasonable person. I am of the same opinion of those I have met from AP and SDS. I do have a bit of an issue by the bashing that AP or anybody else for that matter gets on this site by individuals who have conflicting commerical interests portraying themselves and neutral parties.
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27th August 2008, 07:09	#18 (permalink)
*jradomski* Moderator Current Rebreather/s: Inspiration Classic Sport Kiss Optima rEvo Other CCR Other Rebreather/s: Inspiration Vision Evolution Megalodon Classic Kiss rEvo Other CCR Join Date: Mar 2005 Location: "Da" Bronx Posts: 3,115	Re: Hammerhead's Delrin vs Vision Electronics Mark, I teach and own multiple rebreathers, so my comments are based on my preference.. I couldn't care less if a person purchased a rEvo, HH or inspiration if it was right for their diving. When I do rebreather demos, I always bring the above rigs and some others that I don't teach.. Everyone has a favorite and thats what they will suggest first and thats what I do.. In the next 2 months I have several rEvos that I have sold and have to train people on.. For them it was the right choice.. I also sell KISS rebreathers and still do some training on Inspirations.. I'dsay thats pretty neutral and not locked into one commercial interest.. I like the Explorer for its profiles but frankly the 15 second logging doesnt cut it.. The cochran logs every second.. mine has 1450 hours of logging.. and if I needed it I have another computer.. Its the best for the job so I use it.. DIves like the doria, arent really expedition level dives in my book.. Typical run times are less than 90 minutes.. The britanic dives are more in what I consider expedition level.. I do alot of dives with 4+ hour run times, in that case I want a system I can stay on the loop under anything but a failure of loop integrerity. Just because dives were done on it doesnt mean it was suitable.. People have done dives on the doria with a SINGLE 72... Does that mean it was safe or smart. I have a specific confort level in my equiptment that I want.. I have that level with teh classic electronics, I dont have that with the vision.. __________________ Joe Radomski CCR Trimix Instructor Trainer ANDI Instructor Trainer Director #10 All posts are personal opinions and DO NOT reflect any affiliated agency unless specifically stated. Last edited by jradomski : 27th August 2008 at 23:20.
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27th August 2008, 07:51	#19 (permalink)
Mark Chase RBW Member Current Rebreather/s: Classic Kiss Other Rebreather/s: Inspiration Classic Join Date: Jan 2005 Location: Kent Posts: 2,867	Re: Hammerhead's Delrin vs Vision Electronics Quote: (Originally Posted by Blomman) Isn't the D.P. still under development and can't be bought yet? // Blomman No its available now. ATB Mark __________________ See my "Doing It Chasey" video where I'm locked into a padded room, naked, with two ball bearings and within an Hour, I manage to lose one and break the other!!! Kevin Juergensen 16/11/08 [/quote]
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27th August 2008, 08:17	#20 (permalink)
scunick Nick Cunningham-Moorat Current Rebreather/s: Other CCR Other Rebreather/s: Inspiration Classic Inspiration Vision Other CCR Join Date: Jun 2005 Location: South Africa - Cape Town Posts: 110	Re: Hammerhead's Delrin vs Vision Electronics Just moved to a HH CCR and it is just SO much more robust. I like the electronics and the simplicity of the display and have to date not missed anything I had on the vision handset and really enjoy the redundant handsets. IMHO the HH is a robust independant solution to the problem. Later Nick
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