Reading ohms too low

[Shinn]

New guy warning.

Bought a dna 60 a while back and was worried I'd be getting in over my head, ended working exceptionally well right outta the box.  So I decided to pick up a therion 75C, and now it seems I'm in over my head.

I am having the same issues, ohms seem to be .2 or so off vs my dna60.

Unfortunately I am having difficulty following this thread, I don't mind digging in and figuring it out but am unclear on how or where to change the room temp in escribe.  It's in the low 70s in my shop and the device is reading a room temp 99.3.  I'm not even sure it should read my actual room temp.  Either way I'm getting a poor cold vape.

I would certainly appreciate someone pointing me in the right direction.

Thanks.

 

[Jasonvillamil]

Shinn,

I experienced the same issues as you at first. The Therion comes with default reference settings unfortunately, which means it basically needs to be fully configured before it will give you a good vape. To start, you need to run the Case Analyzer. Set the mod on a table, make sure batteries are about a quarter to a half charged, try to measure the surrounding temp, and let the analyzer run. Be sure to upgrade to the latest version of Escrive first to make sure you don't get an error when you upload the settings. You can optionally attach an atomizer to better represent the full thermal dynamics as when you vape.

That will greatly fix the cold resistance readings and room temp reading. I'd also recommend manually re-reading cold ohms every time your atomizer is cold; this is what the other DNA chips do, and wish the 75C did. 

There are many more settings to configure, such as input and output currents, battery profile, internal resistance etc; I actually just posted a copy of my Escribe settings for this mod, fully configured, to the downloads section of the forum; once approved, take a look for some of these settings in my file if need be. If you'd like a copy now, just let me know. Hope this helps!

[John B]

If you had a settings file with appropriate settings, then you wouldn't need to run case analyzer yourself - the results should be fairly consistent. If you load on Jasonvallamil's settings (from the downloads section) that should get you pretty close. 

 

 

 

 

[ndb]

On 6/6/2017 at 5:08 AM, Jasonvillamil said:

Results from Case Analyzer for Lost Vape Therion DNA 75C:

Case Cooling Time Constant: 155.84 s

Case Heating Time Constant: 317.27 s

Case Static Temp Rise: 10.47 degF

Case USB Connect Temp Rise: 0 degF

Case USB Charge Temp Rise: 23.6 degF/Amp

 

 

I finally had a chance of running case analyzer on my therion 75C. It was with a starting room temp of around 76F, I have no A/C but run it after dinner, so there shouldn't have been any significant increase in room temp during the measurement.

My number are pretty much in line with what @Jasonvillamil found:

Case Cooling Time Constant: 163.33 s

Case Heating Time Constant: 309.16 s

Case Static Temp Rise: 12.01 degF

Case USB Connect Temp Rise: 0 degF

Case USB Charge Temp Rise: 25.1 degF/Amp

 

After uploading those values and letting the mod cool down for almost an hour, I could verify that the room temperature measured by the mod is now much closer to reality, but unfortunately I think there's something more substantial with the 75C with regards to Temperature Control, confirmed by some tests that I did on another 75C mod that I got in the meantime, the VapeDroid X1C2 (which fortunately comes with all thermal properties already set by the modder).

So I'm quite confident I can say what I've found does not seem to be mod related

Cold ohms is still definitively always lower than expected. I have tried the same K5 atomizer, with a 316L coil, and I get (note: all mods have the proper internal res configured in escribe after measuring with a copper plug)

1) vaporshark dna200: 0.837

2) evolv reference mod: 0.83

3) hcigar vt75nano: 0.839

4) smy dna75: 0.833

5) Therion 75C: 0.809

6) VapeDroid X1C2 (75C): 0.805

 

This, of course, leads to a weak vape unless I crank the temperature up from the usual 390/400F that I normally vape, up to 460/470F.

Phil Busardo and Daniel DJLSB have both just released reviews about 75C mods and they both reported exactly the same impression: "You must run TC with higher temperatures than usual".

 

Now, I could accept the fact that we've always been wrong before, i.e. the 75C is more accurate and all previous DNAs were a bit off in TC, but I performed both a cotton-burn and water test on the therion and the VapeDriod, with the same K5 atomizer and same wire profiles (once with evolv stock 316L, and once with the slightly different TFR you can get from steam-engine) and here's what I consistently found:

A) Cotton burn test: cotton just very slightly singed starting from 460F (on all other DNAs this happens since 410F)

B) Water test: fully water-saturated wick, live temperature hovers around 240-270F (on all other DNAs temperature hovers around 210-225F)

 

So I'm now a bit confused, and I say it again: there's something weird with TC on the 75C. It is definitively neither a sensation nor a mod-specific issue (I now have two completely different 75C mods and they do the same thing, and two reviewers have given almost the same exact initial feedback).

My concern is that I've always trusted evolv boards as the only ones where you could treat the set temperature value not just as a number, but something you could rely upon as a reference if you wanted to stay away from dangerous temperatures. More so now that some studies (to which evolv itself contributed with research) are coming out with warnings about potential nasties being released in relation with certain temperature ranges.

I want to keep trusting evolv to keep my vape as safe as possible, so I would really like to hear some official statement about the current status of Temperature Control on the 75C.

 

 

Edited June 9, 2017 by ndb
Specify X1C2 comes already with thermals

[ndb]

While waiting for some feedback from anybody who might shed some light onto this, a quick follow up with a couple of other findings:

Daniel (DJLSB) published a dedicated csv for 316L on the 75C on his website saying it would make temperatures match with previous DNAs.

I tried it and it indeed makes the vape quality much more similar to what I was used to.

Looking at the csv, it seems to be generated by a TCR value (there are only 68F and 800F data points) and given that @800F the resistance factor is ~1,407, this roughly corresponds to a TCR=100 (I'm not considering the 1e-5 multiplier).

The original SS316L has a resistance factor of 1,337 @800F, which roughly corresponds to a TCR=83 (again leaving out the 1e-5 multiplier)

So, this workaround restores, so to say, normal TC behavior (with SS316) with an increase of around (100-83)/83*100 = 20% in TCR.

I honestly don't know what this means in the end, I'm just spitting out some results hoping this might make some bell ring...

[wintergreen]

I will try the .csv  from Daniel (DJLSB) when I get chance.

Hopefully it will make the device a little more useable - even if I have to start using 316L rather than regular 316.

Seems silly to spend money on the most accurate device on the market and then have to guess what temp you are running at. Hopefully we will find out whats going on very soon.

[ndb]

3 hours ago, wintergreen said:

Seems silly to spend money on the most accurate device on the market and then have to guess what temp you are running at. Hopefully we will find out whats going on very soon.

^^^ This! 1K times! I love this board for its customizability. I want to love it for its accuracy too, as I've always loved previous DNAs. Having to go through hoops and tricks as if it was a 20$ chinese board makes absolutely no sense.

I do really hope someone from Evolv gives us some feedback and takes an official position about this.

3 hours ago, wintergreen said:

Hopefully it will make the device a little more useable - even if I have to start using 316L rather than regular 316.

The difference btw 316 and 316L is so negligible with regards to TCR/TFR (just look at the data points of the 2 csvs on steam engine or in Escribe, and you'll see that at all temperatures the resistance factors are pretty much the same) that I'm quite sure you can just take the "workaround" csv from Daniel and use it as it is with 316 too.

Let us know how do you find the vape with it

 

[Shinn]

21 hours ago, Jasonvillamil said:

Shinn,

I experienced the same issues as you at first. The Therion comes with default reference settings unfortunately, which means it basically needs to be fully configured before it will give you a good vape. To start, you need to run the Case Analyzer. Set the mod on a table, make sure batteries are about a quarter to a half charged, try to measure the surrounding temp, and let the analyzer run. Be sure to upgrade to the latest version of Escrive first to make sure you don't get an error when you upload the settings. You can optionally attach an atomizer to better represent the full thermal dynamics as when you vape.

That will greatly fix the cold resistance readings and room temp reading. I'd also recommend manually re-reading cold ohms every time your atomizer is cold; this is what the other DNA chips do, and wish the 75C did. 

There are many more settings to configure, such as input and output currents, battery profile, internal resistance etc; I actually just posted a copy of my Escribe settings for this mod, fully configured, to the downloads section of the forum; once approved, take a look for some of these settings in my file if need be. If you'd like a copy now, just let me know. Hope this helps!

Worked for me, thank you very much. 

I'm getting a good vape now on my dripper same ohms, same temp on both dna 60 and 75c but my single coil ammit is .15 lower on the 75c.  Bummer.

I run 316L only, and will check out the other csv. Downloads.

Please keep in mind I am doing nothing scientific here, still learning and muddling thru it.  I just wanted to say thanks.

MS

[wintergreen]

I have tried the ,csv from Daniel (DJLSB) and it does seem to increase the temperature of the vape a little but now I have no Idea what the actual temperature is, The numbers on the device are no longer an accurate representation.

The ohms reading is still way off where it should be according to all my other devices and Im just guessing what temp Im running at. No doubt I will run into similar problems with other wire types too.

As it stands I really don't want to use the 75c. I just don't like having to guess and bodge it to get anywhere near a decent vape.

[ndb]

On 6/10/2017 at 8:39 AM, wintergreen said:

 

I have tried the ,csv from Daniel (DJLSB) and it does seem to increase the temperature of the vape a little but now I have no Idea what the actual temperature is, The numbers on the device are no longer an accurate representation.

 

Exactly my concern too

On 6/10/2017 at 8:39 AM, wintergreen said:

 

The ohms reading is still way off where it should be according to all my other devices and Im just guessing what temp Im running at. No doubt I will run into similar problems with other wire types too.

 

Yes, definitively reading cold ohms too low, even after fixing the thermal properties of the meod. That seems to only have fixed the room temperature sensing and yes, it'll probably show the same behavior with other wires as well, although I haven't tried anything else than 316L

On 6/10/2017 at 8:39 AM, wintergreen said:

As it stands I really don't want to use the 75c. I just don't like having to guess and bodge it to get anywhere near a decent vape

That's why I'm trying in all ways to get some attention about this issues, hoping Evolv will eventually come back with some explanation/fix. I'm unfortunately not really succeeding for now, gladly welcoming anyone else that might want to voice up...

[James]

Hi @ndb.

Mod resistance... When you measured with a copper plug and Atomizer Analyzer, did you have your mod resistance set to 0? The measurement you get there incorporates the current mod resistance setting (for example, if the whole mod resistance is 0.016 and your mod resistance is already set to 0.004, it will read 0.012). I need to make it show the raw resistance as well, for mod resistance use.

With your 0.800, does it stay fairly consistently near there in Atomizer Analyzer? Or does it bounce around? (I am wondering if certain resistance ranges are less consistent on their cold ohms measurement, and/or if there is a grounding issue.)

 

[ndb]

13 minutes ago, James said:

 

Mod resistance... When you measured with a copper plug and Atomizer Analyzer, did you have your mod resistance set to 0? The measurement you get there incorporates the current mod resistance setting (for example, if the whole mod resistance is 0.016 and your mod resistance is already set to 0.004, it will read 0.012). I need to make it show the raw resistance as well, for mod resistance use.

 

Hi @James, really glad to see your reading this. ;-)

Yes, I first reset mod resistance to 0 (therion came with a 0.004 preset), the copper-plugged the mod and indeed could see a 0.004 in atomizer analyzer. Then, assuming you're using some sort of PID control, to avoid problems with the res becoming negative, I applied a safety reduction factor and set mod resistance to 0,0032, which left atomizer analyzer showing a 0.001, but didn't actually made any improvement to mod performance.

And yes, showing again raw resistance (i.e. Not compensated) would be useful.

18 minutes ago, James said:

With your 0.800, does it stay fairly consistently near there in Atomizer Analyzer? Or does it bounce around? (I am wondering if certain resistance ranges are less consistent on their cold ohms measurement, and/or if there is a grounding issue.)

Yes, it's fairly stable hovering around 0.800-0.802.

While you're here: can you confirm that something changed and a now with a totally dry condition the firmware shuts power down?

I can't seem to be able to evidently singe cotton while trying cotton burn tests..

I'm currently not at home, but tomorrow I can perform any test that you might need to gather further information.

Thanks

[James]

If you are feeling adventurous, try the attached firmware (Tools -> Apply Service Pack) and see if it helps your Cold Ohms measurement.

DNA 75 Color v1_1_SP22_Beta1.sw-service

[Jasonvillamil]

James,

Trying out the provided v1.1.SP22 Beta 1 service pack. Cold ohm reading jumped 0.013 ohms on the first coil tried, and the vape is definitely better. Had to drop TCR for SS316L down from Daniel's 0.001 to 0.00094 to keep from a burnt taste. I'm wording what is new in this firmware release? Was an offset entered in firmware, or something else? Should we be dropping our TCR back down to published resistivity for stainless?

On another note, I've experienced over the last few days that the 75C's cold ohm reading and quality of vape in TC mode greatly depends on the associated room temp reading on the board when the cold ohms were measured. The problem is that I've seen the Therion room temp reading vary greatly, from 65 degF all the way to 88 degF, even when sitting still in a level 73 degF room. I've taken to reading cold ohms, then manually setting the recorded room temp to whatever the board happens to be showing as room temp at the time to get it consistent. Any ideas on this?

Thanks for the beta firmware and input!

Edited June 13, 2017 by Jasonvillamil

[James]

With that firmware, you should certainly use a normal TCR like you would on a DNA 75.

What are the board temperatures doing while the room temperatures are measuring like that, out of curiosity? Personally, I would try our default case thermals. I'm actually fairly skeptical of the DNA 75 Color Case Analyzer as it is implemented in the current Service Pack. In my opinion, its numbers are unreasonably high, and incorrectly aggressive thermals can definitely do what you are seeing. When I get time, I am going to investigate that.

FWIW, if I am reading what you are doing right, you should know: when you measure Cold Ohms, it automatically takes Cold Temperature from Room Temperature. You don't need to do that manually.

[ndb]

34 minutes ago, James said:

If you are feeling adventurous, try the attached firmware (Tools -> Apply Service Pack) and see if it helps your Cold Ohms measurement.

DNA 75 Color v1_1_SP22_Beta1.sw-service

 

Thanks @James , really appreciate your efforts.

I'll be able to test the beta tomorrow and report back as soon as I have a meaningful feedback.

 

[ndb]

Double post

 

Edited June 13, 2017 by ndb
Double post

[John]

If you are always or usually in a temperature controlled environment, try setting the max ambient temp and min ambient temp to a narrower range. 68F to 72 if you are always in AC. 

[ndb]

14 hours ago, ndb said:

Thanks @James , really appreciate your efforts.

I'll be able to test the beta tomorrow and report back as soon as I have a meaningful feedback.

 

 

Ok, here's a first feedback after trying this beta on my therion, with the same K5, same SS316L coil with a "nominal" value of around 0.83ohm when put on all non 75C dnas:

The coil was measured as 0.8299, with a cold temp of 93F (which is a bit higher than normal, as I at the time the room temp was around 83F).

Vape was almost exactly as it was on the evolv reference DNA200 I was used to (vaping at 400F, 17W with a 35W preheat to 380F), of course after restoring the SS316L profile from Steam-Engine (i.e. the one that corresponds to a TCR ~= 84e-5).

Maybe it was even a bit hotter than usual, but definitively a "normal" vape

Then I left the mod rest for about 2.5 hrs and resampled the coil. This time I got a 0.817 ohm @83F, i.e. the room temperature is much more realistic, but cold res dropped quite a bit, and I don't think the difference of 0.8299-0.817=0.0129 can be justified by the lower room temperature (-10F with regard to the first reading) since with that TCR=0.84e-5 a 0.0129 resistance jump should correspond roughly to ~ 33F.

The weird thing is that with this current sampling of 0.817@83F , the vape is not just weaker (I have to up the temp to ~420F to get the same vape as before, no surprise here), but if I remain with a 400F temperature, I get a clearly perceivable pulsing, which can be clearly seen in the screenshot from the device monitor on the device:

 

While the same puff on escribe's device monitor doesn't show all that pulsiness:

That's just maybe a lower sampling rate in escribe's device monitor?

Nonetheless, staying with a set temp of 400F causes pulsiness at almost every puff, and I suspect it will persist until I resample the resistance and get back a value more in the 0.83 range...

@James, for your reference, keep in mind I've restricted the min ambient temp in escribe to 60F (max is still at 110F),  I restored the mod resistance to be 0.004 (as it was originally and as I was able to measure with the copper plug) and that the 316L profile I've used is the csv from SE and not the one that comes with escribe.

Oh, and I'm also using the thermals I got from case analyzer on the therion which pretty much corresponds to the ones found by @Jasonvillamil

A final note: I still can't seem to be able to do a reliable cotton burn test: I was curious to have a feeling for the real temps after applying this beta FW, but I cannot evidently mark cotton even at ~600F, power seems just to be shut off in a totally dry condition.

 

 

 

 

[ndb]

@James, Following up on my previous post: after another ~3 hours of resting, I re-sampled the resistance and this time I got a 0.8253@83F which seemed ok both in terms of resistance and room temperature, and indeed with that baseline everything is working well.

I think I can confirm the beta is definitively working better, I have 2/3 samplings that led to good performance, I'm just unsure if there's still something that might have caused that mis-reading, and if/how that might be related to pulsing.

If you think the thermals obtained with the current version of escribe might be worse than the default ones, I can restore them and see if makes any difference.

I would be happy to hear what you think.

Oh, and did I mention that I'd like to understand what's the story with the dry coil / cotton-burn test? 

[Jasonvillamil]

@James I've had a day with the beta and performance is definitely much better. Tested two single coil builds against my two DNA250 mods and the beta DNA75C, and the resistance readings are spot on. This with 0.004 internal mod resistance as measured, and the 250's set with their own respective internal resistance. 

I did some testing with room temp, and believe that the 75C only seems to update room temp after the mod goes to sleep, or after a reboot. This explains the big jumps I'd mentioned earlier: I'd watch room temp sit at 73 degrees, vape a bit and then let it sleep, with room temp never changing. Picking the mod up ten minutes later then showed a refresh, which would bring room temp way up, as obviously the mod is much warmer after having been used recently. I tried the default profile's thermal settings, but room temp is way off when cold; I decided to instead stay with my results averaged with @ndb's results, and room temp is pretty close to actual when the mod is truly cold. I think what also helped a lot is reducing min and max room temp to a narrower band, 60-90 degrees. Note that after vaping a bit, room temp will always hit the max ambient 90 degrees if I let the mod sleep or do a soft reboot. However, the vape has still been very good, having left the cold ohm reading when the mod was actually cold and room temp was true.

So, much, much happier so far with the DNA75C running the beta firmware! Will try another build this evening and will update if anything weird happens.

Key settings for reference if anyone else wants to try the beta and wants a reference point:

SS316L: Curve set at Stem Engine CSV curve

Therion internal mod resistance: 0.004

Case thermals earlier in this thread

Min ambient of 60, max ambient of 90

[James]

The attached beta firmware fixes the loss of Room Temperature modeling after uploading settings. Since folks tend to edit settings when things go wrong, this should mean a lot less incorrect 90F measurements.

DNA 75 Color v1_1_SP22_Beta2.sw-service

[James]

@ndb, if you go to Tools->Serial Terminal after having it pulsing like that, what does it say if you send the command X=READ DEBUG? Thanks!

Also, for the rest of the folks trying that firmware, I'd be real curious what you get for that value after a while of normal use.  (Sending the command resets it for the next time it's sent. No need to measure it every puff. I am wondering after a session what it is.) I'm expecting around -0.14 for temperature-protected coils, much less for Kanthal.

[ndb]

@James I did some testing with the last cold values (.08253@83F). I did a series of puffs, approximately 3 seconds each, every 5-10 seconds, giving the "X=READ DEBUG" command after each.

The vape parameters where:

COIL: SS316L, Steam-Engine profile

TEMP: 380F

POWER: 17W

PREHEAT: 35W, 365F

I then saved the log of the terminal session and annotated each result with the classification of the puff it refers to:

• REGULAR for a good stable puff for the entire puff duration
• PULSING (PARTIAL) for a puff that pulsed at the beginning of the puff and then stabilized
• PULSING (FULL) for a puff that kept pulsing for the entire duration

Below is the annotated log, and after that, the screenshot taken on the device for the last puff which was the worst in terms of pulsing. (I'm not attaching the screenshots for the other partial as these images are quite heavy and I've no reliable internet connection at the moment, but if you want to see some of them just let me know and I'll upload them too. You can just picture them has being the same as the attached one, with just the power square wave lasting for about just 1/3rd of the puff).

Here we go:

ANNOTATED TERMINAL LOG:

X=READ DEBUG
X=-0.050        REGULAR
X=READ DEBUG
X=-0.097        REGULAR
X=READ DEBUG
X=-0.101        REGULAR
X=READ DEBUG
X=-0.096        REGULAR
X=READ DEBUG
X=-0.098        REGULAR
X=READ DEBUG
X=-0.129        PULSING #1 (FULL)
X=READ DEBUG
X=-0.098        REGULAR
X=READ DEBUG
X=-0.021        REGULAR
X=READ DEBUG
X=-0.096        REGULAR
X=READ DEBUG
X=-0.122        PULSING #2 (PARTIAL)
X=READ DEBUG
X=-0.096        REGULAR
X=READ DEBUG
X=-0.092        PULSING #3 (PARTIAL) 
X=READ DEBUG
X=-0.100        PULSING #4 (PARTIAL) 
X=READ DEBUG
X=-0.096        REGULAR
X=READ DEBUG
X=-0.166        REGULAR
X=READ DEBUG
X=-0.121        REGULAR
X=READ DEBUG
X=-0.122        PULSING #5 (PARTIAL)
X=READ DEBUG
X=-0.080        REGULAR
X=READ DEBUG
X=-0.126        PULSING #6 (PARTIAL) 
X=READ DEBUG
X=-0.224        PULSING #7 (FULL)

 

 

ON-MOD DEVICE MONITOR SCREENSHOT FOR "PULSING #7 (FULL)" PUFF:

 

 

Hope this will be of some use...

 

 

[James]

OK. Well that rules out X=READ DEBUG being the problem. Out of curiosity, what power level is it dropping to there? (To get to the recording, go to Device Monitor -> History -> Download All Recordings). It looks like a current offset issue, to be honest.