Author Topic: Digital Storage Oscilloscopes for Moteino development  (Read 4182 times)

ColinR

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Re: Digital Storage Oscilloscopes for Moteino development
« Reply #15 on: April 16, 2015, 04:18:39 AM »
The other great part about the micro (and USB in general), is that there is no depth limit. Record as much as you want and analyze it later.

I have used the logic features for serial and (slow) SPI and they're great for analysis. A bit of a learning curve, but anything powerful has one.

I forked out the $30 for the bnc probe breakout and use standard 1x/10x probes. I highly recommend some better clips as well.

C
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EloyP

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Re: Digital Storage Oscilloscopes for Moteino development
« Reply #16 on: April 19, 2015, 02:51:07 AM »
The other great part about the micro (and USB in general), is that there is no depth limit. Record as much as you want and analyze it later.

I have used the logic features for serial and (slow) SPI and they're great for analysis. A bit of a learning curve, but anything powerful has one.

I forked out the $30 for the bnc probe breakout and use standard 1x/10x probes. I highly recommend some better clips as well.

C

No kidding regarding the learning curve; I'm still struggling. The BitScope DSO manual is okay, but not so great. The software also seems to have so bugs, but I think it is headed in the right direction.

I also bought the darn Hammerhead (BNC probe for the BitScope Micro). I think it's overpriced but I could not find a better option.

One thing in particular I am struggling a lot with is figuring out how to obtain accurate voltage readings. I don't know if I am using the software incorrectly or if my measurements are somehow affecting circuit behavior.

Cheers,

Eloy Paris.-

EloyP

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Re: Digital Storage Oscilloscopes for Moteino development
« Reply #17 on: April 19, 2015, 04:06:33 AM »
Hi Tom,

this project is probably best debugged on the bench WITHOUT water!  DAMHIKT!  :D

You are absolutely right, but I had some bare spots on my lawn so I reseeded about a month ago and needed to start watering ASAP to keep the seeds wet. I had left two of the old and discontinued Orbit valves (for which I had a working Orbit timer) but I decided to bite the bullet and accelerate completion of my project to control the new generation valves with the end goal of only using the new generation valves starting this watering season. That left me with no option to put in place my controller and debug it while in production  ;)

Sure does!  What's the transport between the Pi and your system in the house?  This is probably the most interesting feature I've seen in some time!  What connection speed does it require?  How do you tell it to move the probes to new contact points? (just kidding!).

I don't have an Ethernet drop in my crawlspace so the Raspberry Pi is connected to my home network via wi-fi (the Raspberry Pi has a wi-fi USB adapter). The actual transport protocol is UDP. I have not seen any problems with the connection over wi-fi. The DSO software for the BitScope Micro has a bandwidth indicator and I don't think I've seen it above 100 KBytes/second. Somewhere I read (can't find the reference now that I am looking for it) that the BitScope Micro doesn't send all samples to the host (connected via USB or through the network via the BitScope Server component). Instead, it sends only the data needed to display the signal.

Yes, I am going into my crawlspace more than ever these days that I am troubleshooting my water valve controller. Fortunately I don't really have to crawl to get where all the stuff is so I can move probes around ;-)

Like I said, thanks for the valuable review!

Least I can do given how willing people are to share knowledge here ;-)

Cheers,

Eloy Paris.-

TomWS

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Re: Digital Storage Oscilloscopes for Moteino development
« Reply #18 on: April 19, 2015, 10:20:25 AM »
<snip>... (connected via USB or through the network via the BitScope Server component). <snip>
So the software running at the BitScope interface is a 'Server Component' that comes with BitScope and you just connect your BitScope client to it via IP?

Cool...

Tom

EloyP

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Re: Digital Storage Oscilloscopes for Moteino development
« Reply #19 on: April 19, 2015, 12:30:30 PM »
Hi Tom,

<snip>... (connected via USB or through the network via the BitScope Server component). <snip>
So the software running at the BitScope interface is a 'Server Component' that comes with BitScope and you just connect your BitScope client to it via IP?

Cool...

Yes, I think so, if I am understanding you correctly. But just in case I misunderstood...

The "BitScope Server" executable is a command-line interface program that runs on the Raspberry Pi. Then the "BitScope DSO" executable is a GUI application that can communicate with the actual BitScope Micro either via direct USB connection, or via IP when the BitScope Micro is connected to a remote computer. In other words, the server component ("BitScope Server") doesn't have a GUI and you don't interact with it for anything other than starting it, and the client component ("BitScope DSO") is what you actually interact with and what display signals, measurements, etc.

On an unrelated note, I'm having problems getting reliable voltage measurements with my BitScope Micro, though. It seems like as soon as I switch the scope probe to 10:1 attenuation the voltage reading changes completely and instead of reading (voltage at the tip)/10 on the scope display I read something completely different, like if the attenuation is not 10:1 but some other factor. I'm currently sitting on my crawlspace investigating ;-)

Cheers,

Eloy Paris.-

TomWS

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Re: Digital Storage Oscilloscopes for Moteino development
« Reply #20 on: April 19, 2015, 01:02:49 PM »
<snip>
On an unrelated note, I'm having problems getting reliable voltage measurements with my BitScope Micro, though. It seems like as soon as I switch the scope probe to 10:1 attenuation the voltage reading changes completely and instead of reading (voltage at the tip)/10 on the scope display I read something completely different, like if the attenuation is not 10:1 but some other factor. I'm currently sitting on my crawlspace investigating ;-)

Cheers,

Eloy Paris.-
Did the 10X probe come with BitScope or was it a probe you bought elsewhere?  The reason I ask is that, typically, 10X probes rely on the input impedance of the 'scope', which is normally 1M Ohm.  If BitScope has a different input impedance then the probe attenuation will not be 10X, but something else...

Tom
BTW, your answer re BitScope server was just what I was looking for, thanks!

EloyP

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Re: Digital Storage Oscilloscopes for Moteino development
« Reply #21 on: April 19, 2015, 01:16:52 PM »
Hi Tom,

Thanks for your comment...

<snip>
On an unrelated note, I'm having problems getting reliable voltage measurements with my BitScope Micro, though. It seems like as soon as I switch the scope probe to 10:1 attenuation the voltage reading changes completely and instead of reading (voltage at the tip)/10 on the scope display I read something completely different, like if the attenuation is not 10:1 but some other factor. I'm currently sitting on my crawlspace investigating ;-)

Did the 10X probe come with BitScope or was it a probe you bought elsewhere?  The reason I ask is that, typically, 10X probes rely on the input impedance of the 'scope', which is normally 1M Ohm.  If BitScope has a different input impedance then the probe attenuation will not be 10X, but something else...

The probe didn't come with the BitScope Micro but it is a standard oscilloscope probe. It is actually this one (the PP150 model):

http://www.hantek.com/en/ProductDetail_15_73.html

According to product specifications, the BitScope Micro is fully compatible with standard oscilloscope probes, i.e. input impedance is 1 MOhm  (it's actually one of their selling points).

I am currently doing a variety of tests (measuring known DC voltages, measuring the signal generated by the BitScope internal wave generator, etc.) with and without the probes and with and without attenuation. I think I will have to contact BitScope support to see what they say and recommend.
Cheers,

Eloy Paris.-