Does anyone do a Meg trimix manual?

**UWSojourner** · 2nd October 2007, 05:23

Quote: (Originally Posted by kieranu)

I, for one would love to know the specific differences between 2.01j (Snap-Tite and Jaksa), 2.01k, 2.06, and 2.5 and their implications. ... Does, for instance, ASP really have a greater improvement on maintaining setpoint on ascent than simply changing the firing rate to longer and more regularly prior to ascending?

Here's my understanding since Mel has not yet replied. Apecs 2.5 has an adaptive setpoint algorithm. Remember, version 2.5 still doesn't have a depth sensor, but the intent of the algorithm is to adapt and increase O2 injection if needed and not increase it if its not needed.

In a nutshell, prior Apecs versions allowed some diver control over the fixed injections via menu options. Version 2.5, in my understanding, should be better in the situation you suggest - ascent. During ascent the injection algorithm should adapt and provide more O2. I had the chance to dive a 2.5 head and I could hear the injections increase on ascent.

Prior to 2.5, fixed injections would continue on ascent and the diver was required to adapt if needed. However, even with 2.5, the diver should be diligent in monitoring PO2. I think the mentality should remain that "electronically assisted" rather than "electronically controlled" would be more accurate and safe. But based on what I can see, the adaptive algorithm should provide a safer range of PO2 needs than the fixed injection algorithm.

Hope that helps.

mempilot · 2nd October 2007, 05:41

Quote: (Originally Posted by UWSojourner)

Prior to 2.5, fixed injections would continue on ascent and the diver was required to adapt if needed. However, even with 2.5, the diver should be diligent in monitoring PO2. I think the mentality should remain that "electronically assisted" rather than "electronically controlled" would be more accurate and safe. But based on what I can see, the adaptive algorithm should provide a safer range of PO2 needs than the fixed injection algorithm.

Hope that helps.

I agree. Deadly time of the dive if one is complacent. I am running Apeks 2.00 with the shotgun solenoid. I kick up the frequency and duration for the ascent, timing my venting of the loop to where I'm at close to zero volume before the shot of O2. I usually switch to 1.4 at my first stop, and have found it difficult to maintain if I leave the solenoid set on the default.

But, we should ask the expert on this. Where's DrMike when you need him? Oooh. Will I get in trouble for that? That is kinda baiting. I'm going back to bed before the storm.

kieranu · 2nd October 2007, 05:43

Quote: (Originally Posted by UWSojourner)

Prior to 2.5, fixed injections would continue on ascent and the diver was required to adapt if needed. However, even with 2.5, the diver should be diligent in monitoring PO2. I think the mentality should remain that "electronically assisted" rather than "electronically controlled" would be more accurate and safe. But based on what I can see, the adaptive algorithm should provide a safer range of PO2 needs than the fixed injection algorithm.

Hope that helps.

I think it SHOULD go without saying that eCCRs (at least as they stand) should be treated as semi-automatic, and monitored, rather than automatic. Anyway, thanks for going out of your way to fill in at least the main differences from 2.01k to 2.5 (and presumably, since they share the same software, 2.06).

cheers,
Kieran

scubagrunt · 2nd October 2007, 06:47

Quote: (Originally Posted by UWSojourner)

Here's my understanding since Mel has not yet replied. Apecs 2.5 has an adaptive setpoint algorithm. Remember, version 2.5 still doesn't have a depth sensor, but the intent of the algorithm is to adapt and increase O2 injection if needed and not increase it if its not needed.

In a nutshell, prior Apecs versions allowed some diver control over the fixed injections via menu options. Version 2.5, in my understanding, should be better in the situation you suggest - ascent. During ascent the injection algorithm should adapt and provide more O2. I had the chance to dive a 2.5 head and I could hear the injections increase on ascent.

Prior to 2.5, fixed injections would continue on ascent and the diver was required to adapt if needed. However, even with 2.5, the diver should be diligent in monitoring PO2. I think the mentality should remain that "electronically assisted" rather than "electronically controlled" would be more accurate and safe. But based on what I can see, the adaptive algorithm should provide a safer range of PO2 needs than the fixed injection algorithm.

Hope that helps.

sorry every free second i have goes to the meg manual.

steveharriss · 2nd October 2007, 06:48

From the 2.5 operating instructions:

"Auto Set Point is designed to be used during rapid descents. ASP is normally selected immediately prior to descent; as the diver descends and PO2 rises, ASP ensures that the PO2 does not fall below current PO2 at any point. Once the descent is complete the diver should select a fixed set point. The diver can select the maximum PO2 that ASP will maintain on the SET MAX SET POINT menu."

I wonder why they recommend it only for the descent portion of the dive? I'd have thought that it would have been just as useful, if not more so, on the ascent? The above instruction seems to take this into account as it mentions not allowing the PO2 to drop, whereas on a descent it's rising anyway??

I have queried this with Meg users actually using the ASP feature and was told that they leave it on for the duration of the dive until they're at their final deco stop. Anyone else got some input on this as it's apparently contrary to ISC instructions?

kieranu · 2nd October 2007, 07:15

Quote: (Originally Posted by steveharriss)

From the 2.5 operating instructions:

"Auto Set Point is designed to be used during rapid descents. ASP is normally selected immediately prior to descent; as the diver descends and PO2 rises, ASP ensures that the PO2 does not fall below current PO2 at any point. Once the descent is complete the diver should select a fixed set point. The diver can select the maximum PO2 that ASP will maintain on the SET MAX SET POINT menu."

I wonder why they recommend it only for the descent portion of the dive? I'd have thought that it would have been just as useful, if not more so, on the ascent? The above instruction seems to take this into account as it mentions not allowing the PO2 to drop, whereas on a descent it's rising anyway??

I have queried this with Meg users actually using the ASP feature and was told that they leave it on for the duration of the dive until they're at their final deco stop. Anyone else got some input on this as it's apparently contrary to ISC instructions?

This is what is my understanding for ASP. However, and this is one thing that has me slightly confused, in addition to ASP on 2.5 there is the concept of AIA (adaptive injection algorithm). Prior to 2.5, the user would select the injection rate (short injection rate time with long pauses between injections during descent vs long injection rate with short pauses between injections during ascent). This also left one open to the danger that on a repetitive dive that the user would leave the high injection rate on and get an O2 spike on the subsequent dive. However, it would appear that with the AIA the user no longer controls the injection rate and this is all determined by the controller and, in theory, should maintain setpoint properly during ascent (and, in conjunction with ASP, on descent). My question would be as to how effectively this works, particularly if you do a standard 9m per minute ascent. I find, for instance, with the Snap-Tite solenoid and 1 second injection every 6 seconds injection rate that it is difficult maintaining setpoint unless I ascend much slower than 9m per minute and/or manually add O2. For non-decompression dives this is rarely an issue, but for decompression dives obviously anything that potentially improves setpoint control without the need for manual intervention is a bonus. Given that the manual gives the new firing ranges at between .25 seconds and 4 seconds I'm guessing that it should work well.

Explorer · 2nd October 2007, 10:38

Quote: (Originally Posted by scubagrunt)

sorry every free second i have goes to the meg manual.

Keep on typing Mel, no time for sleeping, seconds count!!!! Looking forward to the revised ISC MEG MANUAL.

lancsman · 2nd October 2007, 12:47

Mel,

I don't envy you with all the changes that are happening with the MEG. I lookforward to the released manual and improving my limited knowledge of my unit.

Mark

**UWSojourner** · 2nd October 2007, 16:47

Quote: (Originally Posted by scubagrunt)

sorry every free second i have goes to the meg manual.

Seems like your priorities are in order!

Looking forward to seeing it.

MrClive · 2nd October 2007, 17:29

hi mel, will you keep us posted as to when we can order a copy, and d.v.d those will be very welcome. on another note, my ANDI meg mannual is on its way, nice 1 ian.

2nd October 2007, 05:23	#61 (permalink)
UWSojourner Pacific Northwest Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Feb 2005 Location: Portland Oregon Posts: 556	Re: Does anyone do a Meg trimix manual? Quote: (Originally Posted by kieranu) I, for one would love to know the specific differences between 2.01j (Snap-Tite and Jaksa), 2.01k, 2.06, and 2.5 and their implications. ... Does, for instance, ASP really have a greater improvement on maintaining setpoint on ascent than simply changing the firing rate to longer and more regularly prior to ascending? Here's my understanding since Mel has not yet replied. Apecs 2.5 has an adaptive setpoint algorithm. Remember, version 2.5 still doesn't have a depth sensor, but the intent of the algorithm is to adapt and increase O2 injection if needed and not increase it if its not needed. In a nutshell, prior Apecs versions allowed some diver control over the fixed injections via menu options. Version 2.5, in my understanding, should be better in the situation you suggest - ascent. During ascent the injection algorithm should adapt and provide more O2. I had the chance to dive a 2.5 head and I could hear the injections increase on ascent. Prior to 2.5, fixed injections would continue on ascent and the diver was required to adapt if needed. However, even with 2.5, the diver should be diligent in monitoring PO2. I think the mentality should remain that "electronically assisted" rather than "electronically controlled" would be more accurate and safe. But based on what I can see, the adaptive algorithm should provide a safer range of PO2 needs than the fixed injection algorithm. Hope that helps.
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2nd October 2007, 05:41	#62 (permalink)
mempilot What is this..terrafirma? Current Rebreather/s: Megalodon Other Rebreather/s: Megalodon Join Date: Aug 2006 Location: Ft. Lauderdale Posts: 1,269	Re: Does anyone do a Meg trimix manual? Quote: (Originally Posted by UWSojourner) Prior to 2.5, fixed injections would continue on ascent and the diver was required to adapt if needed. However, even with 2.5, the diver should be diligent in monitoring PO2. I think the mentality should remain that "electronically assisted" rather than "electronically controlled" would be more accurate and safe. But based on what I can see, the adaptive algorithm should provide a safer range of PO2 needs than the fixed injection algorithm. Hope that helps. I agree. Deadly time of the dive if one is complacent. I am running Apeks 2.00 with the shotgun solenoid. I kick up the frequency and duration for the ascent, timing my venting of the loop to where I'm at close to zero volume before the shot of O2. I usually switch to 1.4 at my first stop, and have found it difficult to maintain if I leave the solenoid set on the default. But, we should ask the expert on this. Where's DrMike when you need him? Oooh. Will I get in trouble for that? That is kinda baiting. I'm going back to bed before the storm. __________________ MEM "Da Pilot" Black holes are where God divided by zero. "If at first you don't succeed, don't dive silent." "Would you mind not shooting at the thermo-nuclear weapons." ~ Vic Deakins "Donkey's kill more people annually than plane crashes."
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2nd October 2007, 05:43	#63 (permalink)
kieranu Apprentice Meg Pilot Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Sep 2005 Location: WA, Australia Posts: 230	Re: Does anyone do a Meg trimix manual? Quote: (Originally Posted by UWSojourner) Prior to 2.5, fixed injections would continue on ascent and the diver was required to adapt if needed. However, even with 2.5, the diver should be diligent in monitoring PO2. I think the mentality should remain that "electronically assisted" rather than "electronically controlled" would be more accurate and safe. But based on what I can see, the adaptive algorithm should provide a safer range of PO2 needs than the fixed injection algorithm. Hope that helps. I think it SHOULD go without saying that eCCRs (at least as they stand) should be treated as semi-automatic, and monitored, rather than automatic. Anyway, thanks for going out of your way to fill in at least the main differences from 2.01k to 2.5 (and presumably, since they share the same software, 2.06). cheers, Kieran
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2nd October 2007, 06:47	#64 (permalink)
scubagrunt CCR Diva Current Rebreather/s: Inspiration Classic Megalodon Classic Kiss Optima rEvo Other CCR Other SCR Other Rebreather/s: Not Bought Yet Inspiration Classic Inspiration Vision Evolution Megalodon Sport Kiss Classic Kiss Optima rEvo Other CCR Other SCR Join Date: May 2005 Location: Washington Posts: 423	Re: Does anyone do a Meg trimix manual? Quote: (Originally Posted by UWSojourner) Here's my understanding since Mel has not yet replied. Apecs 2.5 has an adaptive setpoint algorithm. Remember, version 2.5 still doesn't have a depth sensor, but the intent of the algorithm is to adapt and increase O2 injection if needed and not increase it if its not needed. In a nutshell, prior Apecs versions allowed some diver control over the fixed injections via menu options. Version 2.5, in my understanding, should be better in the situation you suggest - ascent. During ascent the injection algorithm should adapt and provide more O2. I had the chance to dive a 2.5 head and I could hear the injections increase on ascent. Prior to 2.5, fixed injections would continue on ascent and the diver was required to adapt if needed. However, even with 2.5, the diver should be diligent in monitoring PO2. I think the mentality should remain that "electronically assisted" rather than "electronically controlled" would be more accurate and safe. But based on what I can see, the adaptive algorithm should provide a safer range of PO2 needs than the fixed injection algorithm. Hope that helps. sorry every free second i have goes to the meg manual. __________________ "No good deed goes unpunished!" www.silentscuba.com
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2nd October 2007, 06:48	#65 (permalink)
steveharriss Bubble free by choice Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Sep 2006 Location: North Yorkshire Posts: 163	Re: Does anyone do a Meg trimix manual? From the 2.5 operating instructions: "Auto Set Point is designed to be used during rapid descents. ASP is normally selected immediately prior to descent; as the diver descends and PO2 rises, ASP ensures that the PO2 does not fall below current PO2 at any point. Once the descent is complete the diver should select a fixed set point. The diver can select the maximum PO2 that ASP will maintain on the SET MAX SET POINT menu." I wonder why they recommend it only for the descent portion of the dive? I'd have thought that it would have been just as useful, if not more so, on the ascent? The above instruction seems to take this into account as it mentions not allowing the PO2 to drop, whereas on a descent it's rising anyway?? I have queried this with Meg users actually using the ASP feature and was told that they leave it on for the duration of the dive until they're at their final deco stop. Anyone else got some input on this as it's apparently contrary to ISC instructions? Last edited by steveharriss : 2nd October 2007 at 06:51.
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2nd October 2007, 07:15	#66 (permalink)
kieranu Apprentice Meg Pilot Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Sep 2005 Location: WA, Australia Posts: 230	Re: Does anyone do a Meg trimix manual? Quote: (Originally Posted by steveharriss) From the 2.5 operating instructions: "Auto Set Point is designed to be used during rapid descents. ASP is normally selected immediately prior to descent; as the diver descends and PO2 rises, ASP ensures that the PO2 does not fall below current PO2 at any point. Once the descent is complete the diver should select a fixed set point. The diver can select the maximum PO2 that ASP will maintain on the SET MAX SET POINT menu." I wonder why they recommend it only for the descent portion of the dive? I'd have thought that it would have been just as useful, if not more so, on the ascent? The above instruction seems to take this into account as it mentions not allowing the PO2 to drop, whereas on a descent it's rising anyway?? I have queried this with Meg users actually using the ASP feature and was told that they leave it on for the duration of the dive until they're at their final deco stop. Anyone else got some input on this as it's apparently contrary to ISC instructions? This is what is my understanding for ASP. However, and this is one thing that has me slightly confused, in addition to ASP on 2.5 there is the concept of AIA (adaptive injection algorithm). Prior to 2.5, the user would select the injection rate (short injection rate time with long pauses between injections during descent vs long injection rate with short pauses between injections during ascent). This also left one open to the danger that on a repetitive dive that the user would leave the high injection rate on and get an O2 spike on the subsequent dive. However, it would appear that with the AIA the user no longer controls the injection rate and this is all determined by the controller and, in theory, should maintain setpoint properly during ascent (and, in conjunction with ASP, on descent). My question would be as to how effectively this works, particularly if you do a standard 9m per minute ascent. I find, for instance, with the Snap-Tite solenoid and 1 second injection every 6 seconds injection rate that it is difficult maintaining setpoint unless I ascend much slower than 9m per minute and/or manually add O2. For non-decompression dives this is rarely an issue, but for decompression dives obviously anything that potentially improves setpoint control without the need for manual intervention is a bonus. Given that the manual gives the new firing ranges at between .25 seconds and 4 seconds I'm guessing that it should work well. Last edited by kieranu : 2nd October 2007 at 07:21.
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2nd October 2007, 10:38	#67 (permalink)
Explorer I will teach you a..... Current Rebreather/s: Evolution Megalodon Other Rebreather/s: Join Date: Sep 2005 Location: Alberta, Canada Posts: 760	Re: Does anyone do a Meg trimix manual? Quote: (Originally Posted by scubagrunt) sorry every free second i have goes to the meg manual. Keep on typing Mel, no time for sleeping, seconds count!!!! Looking forward to the revised ISC MEG MANUAL. __________________ REALLY FRICKIN' TRAIN WRECKED.....
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2nd October 2007, 12:47	#68 (permalink)
lancsman New Member Current Rebreather/s: Not Bought Yet Other Rebreather/s: Megalodon Not Bought Yet Join Date: Oct 2005 Location: UK, Flitwick Posts: 60	Re: Does anyone do a Meg trimix manual? Mel, I don't envy you with all the changes that are happening with the MEG. I lookforward to the released manual and improving my limited knowledge of my unit. Mark
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2nd October 2007, 16:47	#69 (permalink)
UWSojourner Pacific Northwest Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Feb 2005 Location: Portland Oregon Posts: 556	Re: Does anyone do a Meg trimix manual? Quote: (Originally Posted by scubagrunt) sorry every free second i have goes to the meg manual. Seems like your priorities are in order! Looking forward to seeing it.
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2nd October 2007, 17:29	#70 (permalink)
MrClive Custom Title Allowed! Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Feb 2007 Location: cork city ireland Posts: 169	Re: Does anyone do a Meg trimix manual? hi mel, will you keep us posted as to when we can order a copy, and d.v.d those will be very welcome. on another note, my ANDI meg mannual is on its way, nice 1 ian. __________________ clive
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