Oh, no. It’s a joke, isn’t it? Then they had could stay with the waterdrop symbol including a number for showing humidity. Maybe it’s not the measuring range but the calibration? See what the Slicer is reporting, when the humidity grows.
I remember the discussion in the other thread regarding humidity sensors. At the moment I see no reason for me to upgrade the AMS to the PRO or HT variant. 
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@simtom Interesting. Well, maybe something else is going on then.
My current AMS humidity levels.
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That might very well explain it. Full disclosure: I haven’t calibrated my AMS2 in this regard. I’m so new to it that I’m not sure whether it is even possible. In fact, I hadn’t even thought that it might be possible. Something to look into. Maybe it is possible, in which case that’s on me, not on the AMS2.
I previously did a lot of work with TH sensors on arduino’s. All of the digital ones were factory calibrated. Maybe the analog ones could be calibrated, but their inherent accuracy was less, so I never used those.
I have no idea what sensor the AMS2 uses. Maybe someday someone will do a teardown, and then we’ll know. That’s probably the shortest path to finding out.
The Switchbot TH module supposedly uses a sensor whose humidity sensor is accurate to plus or minus 2%. I know that some humidity sensors are less accurate at the very low end of the range, though, and I don’t know whether the same is true for the Switchbot TH sensor, as I’m not sure exactly which one it uses, though the amazon listing says " With its built-in industrial Swiss Sensirion sensor you can expect more accuracy up to ± 1.8% RH, ± 0.36 ° F, with a faster and more accurate 4sec sampling" At present, that’s all I know. With many/most humidity sensor chips, there’s a graph somewhere in the chip datasheet which shows the accuracy at different levels of RH. Last time I checked (a year or two ago), TI had the most accurate TH chip on the market that was still reasonable cost, and Sensiron’s latest generation was the second most accurate, but the two were pretty close overall.
You can get higher accuracy at low RH levels by switching to a laser sensing chilled mirror device to measure dew point, but those are more costly because of their added complexity. I’d say there’s probably zero chance of the AMS2 using one of those, as it would for sure be overkill for probably everyone but me. 
OK, a quick check suggests that it cannot be user calibrated. However, to be sure, I’ll ask the official source:
@SupportAssistant Is the humidity sensor in the AMS2 Pro something that the user can calibrate? What is its accuracy?
I use these spool desiccant holders in both my AMS and AMS 2.
Two days ago I used the AMS 2 drying feature hoping it would also reactivate the desiccant in my spool holders. It didn’t fully reactivate the desiccant, so I did it as usual in an oven. Two days after drying the filament in the AMS 2 and drying the desiccant the humidity in my AMS 2 is, if accurate , 4%.
I will be getting the AMS HT for many of the same reasons mentioned by others: high temp filaments, feed the 2nd nozzle, AMS integration, convenience, and price(as it stands now).
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OK, then, if one assumes the accuracy on the AMS2 Pro humidity sensor is plus or minus 5%, which is a very common accuracy for a lot of humidity sensors, then that alone would be consistent with and explain all of the measurements if it just happened that the actual, true, RH percentage in my AMS2 Pro is 5%.
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it knows this with third party too, it just requires believing the user told the printer the truth when they told it the filament.
if someone ruins some PLA because they lied and said it was ABS and ran the dryer too hot for PLA is on them.
More control in the hands of the user is better.
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It’s worth iit FOR ME. I may not use exotic filaments very often, so the main use will simply be the automation of filament loading and unloading from a more convenient location; I don’t need (and don’t really have space for a second AMS2).
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What issues are you having? I am getting a nozzle offset calibration error and its telling me the left nozzle is installed incorrectly or missing. While I can resume the prints and they print fine, I cannot complete calibration without getting z nozzle offset calibration sensor error, which is a big problem. THank God I bought it from Microcenter.
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I don’t have an HT yet but I’m strongly considering it to go with my X1C with 2x AMS. The reason why it is interesting for me:
- I don’t have a dedicated dryer yet and use the print bed for drying, which is not really satisfying. Most cheaper ones don’t achieve the temperatures I want. That alone doesn’t leave me with many options that are cheaper.
- Apart from temperature, an AMS 2 pro isn’t really interesting for me as a dryer, because most of the time, I would have to unload all other roles when I want to dry. A single unit dedicated to drying seems much more convenient to me.
- I’m very space constrained. The AMS HT could directly replace my external spool roller that I currently use for everything othar than the filament in the AMSes.
IRC, it may actually rotate the spool while drying, which is a nice added touch. By turning it into a quasi-rotisserie, you would hopefully get better effective temperature uniformity while drying. Otherwise, with such a cramped space… just not sure you could get the equivalent without rotating it. Some people rotate their spools manually while drying, but automating it is undoubtedly better.
After chatting with Bambulab support I was told that if I need to print any glass or carbon filled filament I must use the AMS HT. If I will use the AMS pro it will get damaged ?
I find this answer a bit strange… first the X1 does not have an AMS-HT and people do use it to print composites.
Secondly I cannot get any ASM-HT so I am stuck with two H2D ordered that cannot print composites 
Any ideas on this issue ?
No problems printing GF/CF in AMS 2 Pro. However if you print a lot of it you can wear out the internal PTFE tubes. I run a lot of ABS-GF and PAHT-CF in AMS/AMS 2 with no problems. On the older AMS the plastic funnels would get worn out with time and need replacement, but on the new AMS 2 they are made from ceramic and much more wear resistant to combat this issue.
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Thanks that was helpful…
I am chatting now with support and finally got a reasonable reply. the AMS-HT can feed better TPU… as far as I see when using the AMS-HT with ASA or PA6 it soften the filament and as such the AMS HT handles softer material better than the AMS pro. This is one reason for using the AMS-HT for TPU, beside other technical grade filaments…
TPU (95A, 90A, 85A) can NOT be auto fed by any AMS. Its too soft so you need to feed it from external spool or with the AMS HT bypass hole that turns it into a glorified external spool holder, auto loading/unloading wont work. TPU for AMS which is almost as stiff as PLA can be fed by AMS, but its not really comparable to regular TPU. Its more like PLA with a tiny bit of flex and abrasion resistance.
There is no difference in the way AMS 2 or HT handle filament. ASA and PA are stiff filaments with a tiny bit of flex, similar to PLA. PA6-CF like TPU can NOT be fed by any AMS as its super stiff and brittle, again you need to use the bypass port or external spool. PA6-GF and PAHT can be fed by AMS and HT as they are slightly more soft and less brittle compared to PA6-CF.
It’s very expensive for something a cereal box would be better at.
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LOL, yeah… probably not the best use of $200, but I’m probably gonna end up doing the same. Even worse… I already have a Polydryer that effectively does the same.
I guess we don’t always make the most prudent decisions.
Can the cereal box dry its own desiccant, meter it all the way down to 0%, Dry nylon, have good rollers, look not like a cereal box, use a brushless motor to feed filament, read rfid, show you the humidity level in software, rotate while drying…Im sure theres more but I just woke up. I think just a dryer that rotates and heats to 65c is about $150, which I believe is the non tariff price of an ht
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