Author Topic: Qoitech Otii  (Read 2184 times)

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Offline Commander_Spock

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Qoitech Otii
« on: January 25, 2019, 10:35:08 am »
i am searching information and real user opinion about the qoitech solution that is described at https://www.qoitech.com/features ?
Is anybody using a Otii arc willing to share opinion about this equipment ?
i understood it is connected to via usb to a pc but is it possible to have an external power supply because the specs shows that it can deliver 5V and 4A and this is way above what a pc usb port can deliver.. do they allow an external power supply to their box ? do they provide it with the box or do they sell it as an option ?
as of now i am reluctant to buy their premium solution as this will be seen as opex and not capex (this is a totally different story to commit money every year rather than to pay only  once something)
 

Offline jeremy

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Re: Qoitech Otii
« Reply #1 on: January 25, 2019, 10:53:54 am »
I don’t have one, but it says on digikey:

Power supply with output voltage range of 0.5 V to 3.75 V when USB powered, up to 5.0 V when powered with optional DC adapter
 

Offline Fungus

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Re: Qoitech Otii
« Reply #2 on: January 25, 2019, 12:29:08 pm »
I don’t have one, but it says on digikey:

Power supply with output voltage range of 0.5 V to 3.75 V when USB powered, up to 5.0 V when powered with optional DC adapter

On the web page provided it says "provides up to 5 V output voltage and runs high resolution current measurements with a sample rate up to 4 ksps for the range of 1 μA - 5 A."

I'm guessing the important part is the part I highlighted in bold. This is a specialist power supply for measuring current on low voltage devices that go to sleep a lot.

Is it any good at that? I don't know. The hardware is straightforward to build so I'm guessing it's mostly down to the software. The software has a trial version and sample data so you can look at it. That's the place to start.
 

Offline Commander_Spock

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Re: Qoitech Otii
« Reply #3 on: January 25, 2019, 01:29:10 pm »
yes this is a power supply that is used to better understand the power consomption of IOT while they are running, transmitting something via wifi/bluetooth/lora/sigfox or sleeping
 

Offline chrfle

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Re: Qoitech Otii
« Reply #4 on: January 25, 2019, 02:20:09 pm »
do they provide it with the box or do they sell it as an option ?

Hello

External power supply is not included. As many users will never need it we decided it would be better to not include it. See the Qoitech FAQ for recommendations on which external power supply to select if you need one.

For some real user feedback, feel free to browse our forum.

Regards
Christer Fletcher
Software developer @ Qoitech
 

Offline Commander_Spock

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Re: Qoitech Otii
« Reply #5 on: January 25, 2019, 07:02:56 pm »
your faq is refering to US version of amazon website do you have any power supply we could buy from amazon in europ (french or belgian or german) amazon website with classic european plug ? A real lab power supply like siglent or korad is good enough or  is it too noisy for your equipment ?
« Last Edit: January 25, 2019, 07:07:00 pm by Commander_Spock »
 

Offline wernerj

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Re: Qoitech Otii
« Reply #6 on: January 26, 2019, 10:35:40 am »
Working for Qoitech. The power supplies we've used a lot are the VEL18US090-xx-JA available with different mains plugs (xx == EU in this case, https://www.digikey.fr/product-detail/fr/xp-power/VEL18US090-EU-JA/1470-3148-ND/5864658) and the VER18US090-JA (https://www.digikey.fr/product-detail/fr/xp-power/VER18US090-JA/1470-3169-ND/5864679) which is the multi mains plug version.

From what I've experienced "any" reasonable lab power supply will work just fine (set to 7.5 - 9V output). What we did encounter issues with were those larger "laptop-charger-style" 5A power supplies, the pulse-skipping at low load on those creates a nasty sawtooth waveform on the 9V output where we can't filter out the very sharp rising edge completely. This will exhibit itself as short (typically negative) current spikes a few microamps in magnitude.

The test if the power supply will work is simple enough:
Hook the power supply up to the DC jack
Don't have anything connected to the main output of the Arc
Perform an offset calibration
Start a recording
You will immediately see the spikes if the power supply is too noisy.
 

Offline Commander_Spock

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Re: Qoitech Otii
« Reply #7 on: January 28, 2019, 09:20:54 pm »
i contacted quoitech today asking if they support labview or mathlab or if their protocol is documented or if they have a sdk in order to code something specific if/when required based on their hardware.... because LUA scripting is very basic and their premium solution is very costly... Yes it is always possible to reverse engineer their protocol and create our own sdk we can open source on github but this is lot of work probably... wait their reply and will share it here...  but anyway power comsumption for iot is a big issue and they seems to have a very nice solution anyway...

nobody used their solution and is willing to share experience ?
« Last Edit: January 28, 2019, 09:27:57 pm by Commander_Spock »
 

Offline jeremy

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Re: Qoitech Otii
« Reply #8 on: January 29, 2019, 12:00:44 am »
Again, I don't have one, I have a N6781A which is a lot more expensive (but also has 200kHz, "simultaneous" ranging, ethernet in the backplane, etc). But if you look at their business model, it seems pretty clear to me that they want you to use their software because that is how they lock you in and make their money. Otherwise why would they have a yearly subscription with all of the associated cloud login stuff? As such, I can't imagine that allowing people to not use their software is high on the list of priorities? And any attempt to write your own low-level software may be met with some resistance.
 

Offline Commander_Spock

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Re: Qoitech Otii
« Reply #9 on: January 29, 2019, 02:19:51 pm »
first did not receive any reply so far from qoitech sales dept showing they are not responsive or unwilling to answer (or both)...
guess you are right but could be fun to reverse engineer the protocol they use on the usb connection and create a small labview/mathlab driver without their help...
Should not be expensive to install a small testbed with a pc and their box with a small arduino in europ and ask one of our indian dev to remotely use wireshark to analyze the usb protocol then code the driver and test all with rdp connection to testbed
nearly sure this could increase the number of unit they sell but probably will destroy they subscription business
« Last Edit: January 29, 2019, 02:25:55 pm by Commander_Spock »
 

Offline glarsson

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Re: Qoitech Otii
« Reply #10 on: January 29, 2019, 02:30:14 pm »
Quite an expensive thing. What does it have that is missing from, for example, a HP/Agilent/Keysight 66319B or 66319D?
 

Offline Commander_Spock

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Re: Qoitech Otii
« Reply #11 on: January 29, 2019, 03:11:39 pm »
unsure my answer is correct but we have several project related to  iot related stuff where power is one of the critical point. imagine an equipment where a singel cell battery should be enough for 5 to 10 years of operation.
we are not interested in how this battery is behaving but we are interested to know how our equipment use power provided by this power source. we need to know that when we do "this" on our equipment we eat "this" power from our power source... with this info our goal is to change our software to use less power...
for example imagine a small drone that look like a jelly fish, it do not swim (required too much energy) but it only follow sea current for years in the open sea, measuring pollution and collect data at different location and depth... every x hours it send some data wirelesly...
this is one of the iot "object" (internet of things) project we are investigating. imagine the same with same sensor but at a fixed location each miles in each rivers of the world ?   
Put this "object" every quarter miles in each street of your city (diretly in the road concrete) and until battery last it will send useful data for years...

here the need is to check that our application software running in this "object" cpu is cleverly designed to minimize power consumption in order to decrease cost of ownership/operation (this object cost wont change but if it can be used twice longer total cost of ownership will be twice smaller)

alll of this kind of "object" will use always less than 5v ...

all this show that yes we need to buy something like the qoitech solution (or something equivalent) but their software is not answering our need at all and a labview/mathlab driver is the minimum required for our automatic tests scenarios where labview/mathlab send a signal to our "object" simulating an evevnt or a measure on a sensor and our software in the object cpu wake up and process this info then go back to sleep.... during all this the qoitech can measure the power comsumption... with these info we can estimate the battery expected life and we know if we are good or need to find better solution that eat less power... yes these test will run 24/7 with various scenario all defined in labview/mathlab that is coordonating everything on this tested

now if somebody has a better idea for our testbed i will be very happy to listen
« Last Edit: January 29, 2019, 03:13:42 pm by Commander_Spock »
 

Offline glarsson

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Re: Qoitech Otii
« Reply #12 on: January 29, 2019, 03:30:18 pm »
Have you looked at a used 66319? This is exactly what this thing is designed to do. It can even simulate a battery with configurable internal impedance and can also sink current to simulate rechargeable batteries.
 

Offline Commander_Spock

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Re: Qoitech Otii
« Reply #13 on: January 29, 2019, 03:36:20 pm »
will take a deeper look but its almost  7 times more expensive than qoitech and keysight website announce it is not available in europ due to rohs compliance issues with european regulations
 

Offline glarsson

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Re: Qoitech Otii
« Reply #14 on: January 29, 2019, 03:45:55 pm »
That's why I wrote "used". It can't be sold new due to RoHS.

It's an old model but there aren't many alternatives. The Otii appeard as a cheaper option but with a subscription.
 

Offline mikeselectricstuff

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Re: Qoitech Otii
« Reply #15 on: January 29, 2019, 04:21:16 pm »
Extra features on a subscription basis - are you shitting me ?
No., Just no.  :palm:
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Offline Commander_Spock

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Re: Qoitech Otii
« Reply #16 on: January 29, 2019, 05:11:33 pm »
received a reply from qoitech sales dept
they offer an api but only for their premium subscription based offer and they write that they see their hardware as"(...) an enabler for our software solution, not a stand-alone product in itself(...)"
so now things are clearer for us... seems we have the solution to by from ebay a used 66319 (that seems to have a gpib port but is a huge box) or a qoitech (a small cheap box but we will have to write our own driver after reverse engineer their usb protocol)...

anybody aware of any other solution ?
 

Offline palpurul

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Re: Qoitech Otii
« Reply #17 on: January 29, 2019, 05:25:13 pm »
I am not even sure if this product is good for measuring power consumption of a low power system such as an IoT device. The bandwidth quite low (400Hz) and noise is not specified for each range (I didn't see any noise information on their website), so I have no way of calculating the dynamic range which is an important parameter for that kind of measurement.



 
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Offline cgroen

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Re: Qoitech Otii
« Reply #18 on: January 29, 2019, 05:30:18 pm »
So this does mean that I have to showel €399,- out every year to use the Premium features (I need the battery simulation) aka Subscription ??
Or is it just something I will have to pay to get updates (for a year) and then afterwards I can continue to use whatever version I'm on ??
 

Offline Commander_Spock

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Re: Qoitech Otii
« Reply #19 on: January 29, 2019, 05:34:28 pm »
in my understanding you have to pay every year their subscription to get their premium solution that include scripting and api.... except if we buy one and code something we open source via github
 

Offline cgroen

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Re: Qoitech Otii
« Reply #20 on: January 29, 2019, 05:47:09 pm »
in my understanding you have to pay every year their subscription to get their premium solution that include scripting and api.... except if we buy one and code something we open source via github

I fear that  |O
There is no way on earth (or any other place in the universe) that we are going to buy test equipment that has a subscription model. Period.
I wish Saleae would do something like this, their analyzer stuff screams for something like this, couple it together with the logic analyzer so you have the power consumption etc sync'ed to the rest of the signals (I have a Pro16 and ABSOLUTELY love it)
 

Offline Commander_Spock

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Re: Qoitech Otii
« Reply #21 on: January 29, 2019, 07:19:56 pm »
we have several lowcost 8 channels chinese logic analyzer but we bought recently a dslogic plus that is pretty good and is working well with sigrok
anyway our i2c or spi bus are so slow that we do not need expensive logic analyzer

for spi/i2c we bought some nice and cheap tool on crowdsupply... received and use the spi and wait for march their i2c... more at https://www.crowdsupply.com/excamera 
« Last Edit: January 29, 2019, 07:34:25 pm by Commander_Spock »
 

Offline andyturk

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Re: Qoitech Otii
« Reply #22 on: January 30, 2019, 01:57:56 am »
I do own an Otii/Arc and use it frequently for projects (with batteries) where power management is important.

Pros:

1. The application is pretty handy. It's easy to just have the thing running all the time collecting data and then zoom into something interesting. When you're able to see the power consumption of your board constantly, it helps build a sense of what's going on. Sending screen grabs of the app is a good way to communicate with co-workers.

2. Physically, it's well built, small, and easy to carry. I've travelled with the Otii a couple of times because I didn't have room to bring another power supply. As long as you can get by with low voltage and not a lot of current, it's fine.

3. It's pretty accurate. I can't say exactly, because I don't have another instrument like it, but it's certainly good enough for making sure you're going into sleep mode and verifying that your battery charger is configured correctly.

Cons:

1. Not cheap. I paid something like $600 USD for the device without the subscription B.S. FWIW, I loaned it to another engineer friend and he ended up buying one too for his very low-power project.

2. Very limited capability as a power supply. It's great that the thing can supply power from only a USB connection, but that limits the voltage to (can't remember exactly) 4 volts or so. Not a whole lot of current either, but probably enough if you're only charging 200mAh batteries. You can plug in a 9V brick to supply more than 4V, but the brick is annoying and it's still a very low output. The device would be a lot more useful if it could pull more than 500mA from USB and boost/buck it to a larger range of voltages. And when the external power brick is attached, it should clearly be able to provide more power than it does.

3. It's got a stupid micro-USB receptacle. There was plenty of room for a larger USB B type receptacle that would be more durable.
« Last Edit: January 30, 2019, 02:00:49 am by andyturk »
 
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Offline Commander_Spock

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Re: Qoitech Otii
« Reply #23 on: January 30, 2019, 10:28:44 am »
found maybe another solution using an high side current monitor using chips like ina219 or ina3221 and bought two small board using these chips from aliexpress in order to test (yes we will have to wait due to chinese new year as all stop in china for 2 weeks)
unsure if precision will be good enough but these chips measure current and send result via i2c bus. if we use a cheap  esp32 we could get result via wifi or bluetooth and it is then easy to integrate all in our automatic testbed
still unconvinced that a 20 usd solution would produce same result/precision than qoitec this is why i do not rule out using qoitec at some point in the future but clearly we will not buy their subscription based premium solution

for more on this possible solution take a look at https://tech.scargill.net/ina3221-triple-voltage-current-monitor/  and http://henrysbench.capnfatz.com/henrys-bench/arduino-current-measurements/ina219-arduino-current-sensor-voltmeter-tutorial-quick-start/
 

Offline jeremy

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Re: Qoitech Otii
« Reply #24 on: January 30, 2019, 11:12:39 am »
As far as I know, there are 3 ways to solve this problem:

1. regulator with remote sense => Current sense resistor => high gain differential amplifier => high resolution ADC (this is what this device seems to use). Depending on how you set up your remote sense, you can hide the voltage drop across the current sense resistor. Downside is that you need some sort of range switching to take place, and you can lose resolution on different ranges (aka limited dynamic range).

2. Energy metering by pumping "packets" of charge into a storage device and measuring how many packets you send. I haven't seen this in a real device, but it may exist?

3. Use a calibrated mosfet with a known V/I curve as a variable current sense resistor, but otherwise similar to option 1. I imagine it is quite complicated to get the feedback loop right, but it means that you can use a lower resolution ADC and as such a faster sample rate. I think the N6781A uses this approach with an 18 bit ADC @ 200khz to achieve an "effective" dynamic range of 28 bits (or so they claim). To be honest, I can't test it, because on paper this device is probably the most accurate in this type of instrument that I own. I suspect that the N6781A does low side current sensing so that mosfets are available with the lowest Rdson possible. One thing I can tell you is that for a 6V/1A supply, it uses some serious cooling in the various backplanes, so it must be generating a lot of heat.

Also, a lot of work needs to go into leakage. You're talking <1uA in some of these use cases and you need guard traces, shielding etc to minimise leakage. Note that in the photos of this device, the current sense region has lots of large holes around it to presumably reduce leakage and to reduce thermal coupling to the regulator and rest of the main PCB.
 

Offline mikeselectricstuff

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Re: Qoitech Otii
« Reply #25 on: January 30, 2019, 12:38:55 pm »
I've looked at this problem a few times over the years.
My conclusion is that the easiest way to do it is to use a voltage regulator with a consistent, known quiescent current, and measure the input current. This addresses the issue of voltage drop across a sensing resistor.
To deal with the wide range, about 3 sensing R's in series, with bypass diodes to limit the voltage across them to about 1V.
Measure the voltage across all 3 simultaneously, and select the one that's in range.

I've also looked at the "charge bucket" approach with capacitors, but leakage and nonlinearities make this a non-starter

In practice it is often possible to avoid the need for special testgear by manually forcing various modes, measuring the current in each, then looking at the time spent in each mode in normal operation.
Batteries are not precision devices, so you don't need to measure avarage draw accurately - 10% is easly good enough
 


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Offline jeremy

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Re: Qoitech Otii
« Reply #26 on: January 30, 2019, 12:56:57 pm »
Yes, I agree that 10% is probably ok for most applications. Sadly though, a lot of these instruments do give people a false sense of security about how precise batteries are, and of course nobody is going to correct them if it sells less meters...

I recently read a R&S white paper on measuring radio module current and estimating battery life. It was basically just: if you buy our $50k instrument, it will tell you that your device sending a tiny packet once per week can last 19 years on a rechargeable lipo(assuming no self-discharge) :palm:
 

Offline Apollyon25_

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Re: Qoitech Otii
« Reply #27 on: January 31, 2019, 12:35:55 am »
At one of my work places, we have two Otii Arc's, and I've found them extremely versatile for measuring the current consumption of our IoT remote trigger device.

We've used it to qualify our coin cell battery (Primary Li), optimise our FW for sleep mode currents and wake periods, as well as characterise the various operating modes we'd see while awake.

I've used it to fix a quirk with our implementation of an ST Microelectronics battery charger IC, used with a larger Li-ion battery pack, and have used it as a general PSU and volt/current meter a few times. I've used its GPIO and ADC/Sense channels just as a readily useable scope/logic analyser...

I've used it to qualify our changes to our app, between various versions of the Tizen OS on the various generations of the Samsung watch, and it's been used to direct how our app behaves to obtain the best battery life without limiting our product features too much.

Sure, the scripting is a premium feature, and you pay for this with a subscription model. This isn't too different to many software licencing arrangements, and I can understand some people's reluctance to support such a sales model.

I've found their support exemplary! They've helped debug my setups, my scripts, and they've updated FW and app for me specifically to address any issues I've come up against. They take UI improvement suggestions on-board, and even updated me when a few of these were implemented.

I looked at a bunch of Keysight gear to do much the same (battery emulation) and I needed three bits of kit and none of them were cheap.

It works for me.
 
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Offline EEEnthusiast

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Re: Qoitech Otii
« Reply #28 on: May 01, 2019, 05:45:37 am »
You might want to consider the ZS-2102-A from ZSCircuits. It does what the Otii Arc can do and much more. It has a higher bandwidth with a pulse response time of < 2uS. It samples at 1Msps and has a dynamic range of -1A to 1A. With 1uA accuracy and less than 100nA resolution for average measurements. It can measure negative currents as well which is useful in some IOT devices which may use solar cells or buck boost converters which can feed currents back to the battery. And the software is free.
 
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Offline julianhigginson

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Re: Qoitech Otii
« Reply #29 on: August 12, 2019, 05:05:56 am »
I saw this today, and was really interested in it at first glance, but soured a bit on further reading.
I figured someone on here would have has some opinions already.. ;-)

The sampling rate is a bit lower than I'd prefer, but the breakdown between basic features and subscription features is the dealbreaker.  It's a shame, because with battery profiling/simulation capability outside the subscription model, it'd be pretty much perfect for a lot of things I've worked on in the past and will work on in future.

I see the point of needing an ongoing income source for keeping computer software (which is a major component of this instrument by the looks of it) up to date and working and growing...  it just seems that this isn't making the tradeoff quite right. Especially for a small company with just one product that we have no guarantee will even be around in another year.
 

Offline julianhigginson

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Re: Qoitech Otii
« Reply #30 on: August 12, 2019, 05:07:40 am »
that zscircuits option looks interesting.
 

Offline EEEnthusiast

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Re: Qoitech Otii
« Reply #31 on: September 12, 2019, 07:12:12 am »
I forgot to mention that I am the designer for the ZS-2102-A. My apologies.
 


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