Please put a Temp Lock option in software!!!

[Mad Scientist]

The N80 wrap will actually slightly lower the already low TCR of SS for the build as a whole. Can you wrap with SS?

[Droopydroors]

scoopy said:

K I said I agreed with that part of it......but I promise u it's thenl wire/curve.......I've read a ton about this and how to fix it......steam engine has some curves mixed up for certain grade ss..........I've tried explaining this the best I know how......ure answers are on these forums.....I understand u r hostility but it can be fixed

Dude no hostility. And like I have said I have already searched the forums and have found the answer as well as used separate tcr curves that are not from steam engine. Thats not what this is about. It's trying to get them to fix the problem of jumping out of temp mode. Thats it, that's all, nothing else, I don't need help, I appreciate it but don't need it. If I need it I will be sure to hit you up. But this is trying to get them to fix an issue that can be dangerous. Do you work for evolv? If so then fix this. If not then if you can push this to someone that does before someone gets hurt and blames it on evolv.

[scoopy]

With the right wire it's works spot on......They never never said use SS......actually.said to stay away from it......that post nos on her e to

[Bapgood]

Droopydroors you said you got it fixed. What was the solution?

[Droopydroors]

Bapgood said:

Droopydroors you said you got it fixed. What was the solution?

It seems as though the resistance lock fixed the problem. For the most part. Right now my settings are. Resistance reading .05 locked 90 watts 380 temp 150 preheat at .7 seconds 5 on punch The coils are dual 2x22g ss 316L elite core / 38g n80 alien fused wrap / 3mm id / 4-5 wrap / Custom TCR uploaded. It is running very true to temperature and running very steady at the 380 mark. Since ss does hold temp alot more than ni200 and Ti the preheat seems to only kick in when the coil is down at room temp. Which is exactly what I was expecting and wanted. It makes sense that if the coil is still warm, from being in the middle of a little vape session, that the pre heat isn't needed due to holding the temperature. As you can imagine these coils are quite large so the preheat is such a nice feature to have. But only if it is set correctly and works as it should. So I'm very pleased with this aspect of the chip. And is why I'm trying this little experiment. Prior to this point no device could do this in temp control and I believe that's why there is an option for 200 watts available in temp mode for this device.

[Mad Scientist]

Here's an example of a "runaway" coil: Test setup: plume veil with .005" type-E thermocouple fitted to central wrap of 3 wraps 26 AWG Ti; Ocean Controls thermocouple board with added PIC12F675 programmed to interface to PC (the 8 pin PIC is in a 14 pin dip socket because I might go with a 16 series PIC down the road). The PIC reads the temp and sends ASCII csv values to the PC. These are then saved to .csv file and charted with Excel. Data points are 100ms apart (10 per second). Data is presented as degrees C. The first tiny little increase hump was, I believe, the DNA 200 reading resistance. Then the first two smallish "humps" in the chart are quick clicks to lock, set desired temp, then quick clicks to unlock. DNA 200 is fantastically fast to fire as these were very quick clicks. It started heating a little at each set of 3 quick clicks. Best performance of any mod I've used. DNA 200 set to 100W preheat for 1 sec punch 7, then 75 W max. The huge spike is the first fire on the coil, almost 470 degrees C peak (!). The second nice plateaued line is the second fire, normal temp regulation. The DNA 200 obviously didn't like something about the coil on the first fire. It immediately "settled down" for the second fire.

[blueridgedog]

I am curious about the implications here.  I have tried various twisted and wrapped coils and some do indeed fall into non-tc mode.  Most of the time I deduce that it is user error in the assembly or an atomizer issue.  I can't see how telling the chip to force TC mode would adjust this as it would still keep flooding the watts to see the resistance change it is looking for (based on the curve you have loaded).  So, how would the chip act differently if you had the option to force TC mode?

Personally, I think the only answer is to limit available watts in non-TC mode and to build accurately.  

[VapingBad]

Very good point Blueridgedog, it would make it worse as once pre-heat is done the watts will never exceed the max significantly as I understand it.

[James]

The DNA does not have modes. It has a single unified control system.

When we detect a temperature-sensing coil, the only difference is that we enable preheat to improve the experience from cold. Preheat ups the maximum power delivered power until the coil is at the appropriate temperature or after the preheat time has passed.

The temperature protection code is in effect at all times. If you have it set to 40W and 400F, with no preheat, it will happily deliver 40W until it reaches 400F, and then lower the power so as to stay within safe temperatures. It has to know the correct cold resistance, though.

If you are getting burnt hits, the cold resistance from the DNA to the coil may not be a single stable resistance. This is usually caused by an unstable connection or a badly-designed 510.

If the hits become burnt half-way through usage, the cold resistance may have changed. This can be caused by coils shorting, unstable connections, or wires that are undersized for the amount of power being thrown around (this last one can be... interesting... if you watch the resistance in Device Monitor... creatively bouncy, let's say?).

Dual coils are a special challenge, because if the two coils do not have exactly matched cold resistance, you are going to get differing amounts of power going through each of them, and one is going to be hotter than the other.

James

[VapingBad]

Thanks James that is very interesting.

Maybe it is just semantics and context, but I think most people understand it as two distinct modes. While your post doesn't conflict with what Brandon said here you see the confusion that even though there is not a distinct temp mode in code (but there will be conditionals) there are 2 modes of behaviour from the users perspective.

[James]

The screen does change between showing voltage and temperature based on whether it has detected a temperature-sensing coil, so that is understandable. Still, a burnt hit doesn't come a mode change in the the control system.

[Rebelgolfer72]

I believe the devil is in the details here. The nature of the type of coil that you are using (I think you said some type of "Clapton coil" variant...which now makes the heating wire into a heating "cable"), relies on the oxidation of the wire to insulate the various strands and wraps of the wire from each other. In reality, you are only directly heating the lower resistance core wire, and the current flow through the longer, thinner wraps that are in parallel to it is minimal. As a result, these wraps are not being heated by the current, but actually getting most of their heat indirectly from the hotter core wires. So by nature, the resistance of the heating cable is not extremely stable in and of itself. This also compounds the stability of the connection to the atty. I really believe that this is one of those cases where people are asking too much from the boards in terms of regulating temperature. A close second to this is the use of long, heavy gauge wire. These heavier wires require a ton of energy to be dumped in to them in order to heat them. Once they get close, or overshoot, the only thing that can be done is cut power -- there is no way for the board to stop the heat or reverse it. It's like trying to stop a locomotive vs trying to stop a Prius. By the nature of things, I believe that the shorter and thinner your coil wire is will yield the best accuracy in TC, as it will heat faster AND cool faster so will respond much better to the power modulation used to control the temp. An analogy to this would be the difference in how a light Corvette handles a fast, winding road vs how a heavy pickup truck with a 12" lift and oversized tires would handle the same road. From my experience years ago in programming the automated cycles of resistance welding/brazing machines, I can tell you that you have to approach heating metals with more mass quite differently than lower mass materials. With lower mass materials, you can simply fluctuate the power to regulate the temp. With materials of higher mass, your best accuracy isn't with consistent and modulate power, but by pulsing the heat-- having alternating short pulses to heat, and rests or cooling cycles between the pulses-- allowing the mass of the metal to stabilize. I've also found that with trying to use the DNA200 with stainless, by taking the approach of using the same power setting I would in power mode, using a conservative 20% boost in that for a short preheat and adjusting the temperature limit to really only take the overheating that would occur at the tail end of the puff out works the best. I approach it like I would with compression/limiting in the music/broadcast industry.

[bilboda]

Interesting read that leads me to a question from James' comment about wire size and power.
How would one determine that there wire is undersized for the set power? I have 26, 28 and 30 gauge.
Outside of there own native resistance, should I expect any different behavior from each wire?

And a comment.
We take a device designed to measure temperature through resistance changes in a single wire with known, reliable coefficients and decide to use complex builds of home wrapped wire in single, dual, quad, etc. coils whose coefficient can only be measured in theory for a perfectly built wire, and you aren't making those.

There have to be imperfections in the build, there always are and when you take that straight clapton wire and shape it into a coil, you are introducing new imperfections. And you are not considering the heat sinking that has to occur with the different wires/resistances. No matter what curve you use, it would be blind luck that you will get one that matches your custom wire. Not to mention the changes it goes thru during use and over time.

A Temp Lock cannot be done if your temp cannot be determined.

Stick with what is known and you will be fine, for the most part. Experiment at your own risk, but it will be no one's fault but your own if that does not work well

[Mad Scientist]

bilboda said:

Interesting read that leads me to a question from James' comment about wire size and power.
How would one determine that there wire is undersized for the set power? I have 26, 28 and 30 gauge.
Outside of there own native resistance, should I expect any different behavior from each wire?

And a comment.
We take a device designed to measure temperature through resistance changes in a single wire with known, reliable coefficients and decide to use complex builds of home wrapped wire in single, dual, quad, etc. coils whose coefficient can only be measured in theory for a perfectly built wire, and you aren't making those.

There have to be imperfections in the build, there always are and when you take that straight clapton wire and shape it into a coil, you are introducing new imperfections. And you are not considering the heat sinking that has to occur with the different wires/resistances. No matter what curve you use, it would be blind luck that you will get one that matches your custom wire. Not to mention the changes it goes thru during use and over time.

A Temp Lock cannot be done if your temp cannot be determined.

Stick with what is known and you will be fine, for the most part. Experiment at your own risk, but it will be no one's fault but your own if that does not work well

As another perspective, the gauge of the wire determines its surface area and thus the volume of juice it can flash boil at a set temperature.  A wire is undersized for an amount of power if basically the heat per area exceeds an amount typically "known" to produce an acceptable result with wick and juice.  Steam engine will give you that calculation and display whether from the result a build will be "hot."  Thinner wire heats less surface area and so can produce acceptable vape with less power than a thicker wire which will produce more vapor with more power.  Thin wire with more power will either be temp limited or, if not temp protected, burn the juice and wick.  The opposite is true for thick wire.  Not enough power for the surface area makes a weak vape.  It's just a function of total heat (power) distributed over the surface area in contact with juice.

Clapton wires are interesting because that idea was a clever invention (I believe from the mech crowd) to increase wire surface area without overly decreasing resistance as with just a thicker wire, so it would work on a mech.  It also self wicks some juice (although this is just more surface area in contact with juice, so it behaves as a wire even thicker than its diameter).

Every conducting metal composition has a TCR regardless of thickness or shape, and for making a wire and building it into a coil, as long as the build is stable, the average temperature of the entire length can be determined by its change in resistance (with a known starting temp).  This is true regardless of the thickness or length of the wire.  

Clapton wires are no exception.  They can be unstable, but for the most part are not.  The key is to make them so the final result has no resistance change caused by thermal movement.  Given I can do it, I conclude it isn't hard to do lol. The average temp delivered may not match an exact predicted set temp for some of the reasons you mention, but it will be consistent and repeatable, not to mention surprisingly close to predicted.

[Rebelgolfer72]

Ideally, to handle all wire sizes, ther would have to be 2 different (selectable) methods for controlling temperature. The straight power modulation like it has now works best from my experience with 28g and smaller wire (single coil). For heavier wires, I believe a pulsing type method of heating would work the best-- but then you would have folks that wouldn't like the fact that they can feel (or hear) the pulses in the Vape. FWIW, I had 0 problems using temp control with stock Aspire Triton coils (0.4?, 24g, 317L stainless)- however I was conservative with the preheat, used the Sam wattage I use running in power mode (36.5W), and set th temperature at about 440°, just to catch the tail end of longer vapes....in fact, this was probably the best Vape I ever had. Now I just need to get my DNA200 repaired/replaced...been almost a day, and I alread miss it!

[Xx3dge]

James said:

The DNA does not have modes. It has a single unified control system.

When we detect a temperature-sensing coil, the only difference is that we enable preheat to improve the experience from cold. Preheat ups the maximum power delivered power until the coil is at the appropriate temperature or after the preheat time has passed.

The temperature protection code is in effect at all times. If you have it set to 40W and 400F, with no preheat, it will happily deliver 40W until it reaches 400F, and then lower the power so as to stay within safe temperatures. It has to know the correct cold resistance, though.

If you are getting burnt hits, the cold resistance from the DNA to the coil may not be a single stable resistance. This is usually caused by an unstable connection or a badly-designed 510.

If the hits become burnt half-way through usage, the cold resistance may have changed. This can be caused by coils shorting, unstable connections, or wires that are undersized for the amount of power being thrown around (this last one can be... interesting... if you watch the resistance in Device Monitor... creatively bouncy, let's say?).

Dual coils are a special challenge, because if the two coils do not have exactly matched cold resistance, you are going to get differing amounts of power going through each of them, and one is going to be hotter than the other.

James

what ive been doing for dual coils is working pretty good. i cut two wires exactly the same length and wrap my coil and install without cutting any of the wire. I use steam engine to find out the exact length needed for my build.

[blueridgedog]

Speaking of reliable atomizers...Any recommendations for a great tank/RTA?

[JaySoCal]

Been loving my stream crave aromamizer with velocity style deck. Easy to build on great flavor and clouds