Magnova oscilloscope

[Scottjd]

I recently got a trade for a 121GW meter. The previous owner did a great job calibrating DCV (thanks Scott!), but didn't have the tools to do ACV.

Nice! It’s looking good. Yea, I need to step up my cal source game.

[KungFuJosh]

I recently got a trade for a 121GW meter. The previous owner did a great job calibrating DCV (thanks Scott!), but didn't have the tools to do ACV.

Nice! It’s looking good. Yea, I need to step up my cal source game.

It's really bad, man. I keep seeing calibrators and nice AC/DC sources that cost big money and then I have to remind myself that I can send all my meters out a bunch of times for pro calibration for less money. Now, if somebody offered me one in trade, I'd take it anyway. 

[Andre77]

Thank you all for your valuable input! We have read each suggestion with great interest and will incorporate anything that is currently feasible or particularly interesting into our ongoing development. Some suggestions can be implemented quickly; others will take more time. However, rest assured that everything will be taken into account and influence our decisions.

After playing around with the functions, especially with the math channels,
I think it would be a great feature, if we could use this also as trigger input.
(not sure if this even possible or how slow the reaction time would be :-)

Direct triggering on a math channel is difficult. The R&S MXO3/4/5 scopes allow using zone triggers on math channels, but the zone trigger is a special case: it is applied after the acquisition and filters the captured waveforms. The actual acquisition still relies on a standard trigger.

The MSO is a 'must have' since the serial decoder is already implemented.
But here I would prefer another way to display the captured data.
Most protocols are using some type of termination byte to seperate junks of data.
So maybe we can have an opion to group the data (e.g. until <CR> or after 1ms IDLE time)
Also as 'how to visualize digital signals':
here a screenshot from a xilinx GUI:
Over all, a very good scope.

We’re already working on a packet-based view in the table, which should make it into one of the upcoming updates.

What do you especially like about the Xilinx GUI display? Bundling multiple digital lines is already possible using the parallel decoders (see screenshot below).

My suggestion for the horizontal axis:
1. get rid of the "s" in the units -> that's a redundant information
2. use the same unit for all the values -> change "800u" into "0.8m" if all other values are in "m"
3. center the values to the grid
4. add the values at the top of the grid or at the bottom, not on both edges
5. maybe mark only every second grid -> that should be enough

Thank you for the list and for providing a visualisation of the graphic adjustments. Some of these things are probably also a matter of taste. For example, if the timeline says '0.8m' instead of '0.8ms', somebody might initially think it meant 0.8 minutes instead of 0.8 milliseconds. But additional setting options would certainly be helpful for customising it to everyone's liking.

[Andre77]

Adding to that:
An snap function to snap in a magnetic way to more integer values when scrolling X or Y when using the touch screen would be cool. When trying to get trigger offset back to exactly 0s or y offset to 0V(for pure psychological reasons) or any other 1/10th  fraction relative to x/div or y/div it is quite hard to do so without falling back on using the rotary buttons.
This is the same for all other toucjscreen scopes I saw so far. Always wondered why that's never done. It could be a configuration option for those who don't want this.

There is already a snap function. When using a mouse, you can click and drag a channel marker or the trigger position marker with the right mouse button. The level or time position will then snap to fifth-of-a-div steps.

For touchscreen operation, this works by using a second finger. First, touch and drag the channel or trigger marker with one finger. Then place a second finger on the screen, and the movement will snap to fifth-of-a-div steps.

[KungFuJosh]

Thank you for the list and for providing a visualisation of the graphic adjustments. Some of these things are probably also a matter of taste. For example, if the timeline says '0.8m' instead of '0.8ms', somebody might initially think it meant 0.8 minutes instead of 0.8 milliseconds. But additional setting options would certainly be helpful for customising it to everyone's liking.

Yes, please. Options are better than forcing anything. I prefer the 0.8ms over any vague values. I don't generally like when the specific value type isn't defined.

[john74]

What do you especially like about the Xilinx GUI display?

Sometimes I find it easier to differentiate a "lo signal" from a "hi signal" , when the high signal is filled, especially when there are not that many level changes on the screen.
(as example I attached a 4bit parallel signal....which value has the bit3..."lo" or "hi" ?)

But again, if you ask 10 people ... you get 10 different style wishes...one would be "give me a color table with hex-codes" :-)
So don't feel forced to implement it all and stick on your design rules.

But I think the 6 digits decimal places is a "bug" because it apears only in "V". When the unit is "mV" the values are rounded to 3 digits max.

There is already a snap function. When using a mouse, you can click and drag a channel marker or the trigger position marker with the right mouse button. The level or time position will then snap to fifth-of-a-div steps.

that' new to me and very handy.

[john74]

quick followup,
here another design idea to display digital signals
(with a transparent background)

 

[KungFuJosh]

I like the channel specific transparent background colors, but I don't like the kinda cheesy gradient overlay lines.

[Andre77]

Now that you mentioned the math channels: Are there already any plans to provide more math functions?
We really miss some filters, especially low pass filters, as a math function.

We definitely want to support filters for math functions, but it will take a while. Unfortunately, I can't say when that will be.

Another thing which we missed this week in the lab: Having the measurements update in roll mode as well. I'm not entirely sure how they should be triggered and over which time interval they would best be implemented, but I'm sure something could be figured out.
Our application was: We measured the output of an amplifier for a strain gauge full bridge with quite a bit of noise coupling and wanted to view the trend chart of the RMS measurement. Unfortunately that is not possible in roll mode.
Maybe in roll mode the user can enter the time interval over which the measurement function works? Like: Newest 2s or something like that.

Measurements in roll mode would indeed be useful for several applications.
We will look into this and see if we can implement it in one of the next updates.

Thanks for your suggestions!

[Andre77]

I recently got a trade for a 121GW meter. The previous owner did a great job calibrating DCV (thanks Scott!), but didn't have the tools to do ACV. [...]
Then I remembed the Magnova's AWG has more resolution. And it worked! My only complaint is that in the mVrms range, I could only adjust 2 decimal places, as the 3rd decimal was locked at 0.
Feature request: If possible, it would be awesome if that 3rd decimal place could be adjusted in the mV range.
Even with that limitation, I got some great results. Being able to adjust to 5 decimal places in the Vrms range made a huge difference!

Thank you very much for your post and your feature request, Josh!

A resolution of 10 µVrms is already fine for a generator. However, I will gladly take your suggestion into consideration and see if the 1 µVrms setting can be supported (at low output voltages).

I understand that you would like to use the Vrms unit for multimeter calibration. Since the goal is to achieve the finest possible setting, you could switch to the Vpp unit after making an initial setting at Vrms. With the Vpp unit, you can set up to 10 µVpp. Thus, the adjustment steps are around three times smaller and more accurate (10 µVpp -> ~3.5355 µVrms). Of course, this would only be a workaround, but it would result in a significantly more accurate resolution step.

[Andre77]

With Siglent Scopes (and not only there), the axis labels can be:
-Fixed or floating
-Left-aligned, right-aligned, or centered
-Completely disabled...
That would indeed be a useful addition to Magnova.

Thank you very much for your suggestions, Martin!

Yes, the optional floating grid on the Siglent scopes is really nice.

Being able to adjust the position of the grid labels is also a handy feature. I have a feeling it’s not something most users change often, but I might be wrong.

[2N3055]

Being able to adjust the position of the grid labels is also a handy feature. I have a feeling it’s not something most users change often, but I might be wrong.

It is one of those things that you use a lot once you have it....
Depending on how busy the screen is , you sometimes shift things around.
Especially when documenting something.
I would call it not mandatory but sometimes very useful to have.

And you know how they say, it is not important until you really need it ... 

Best,

[Martin72]

For example, with FFT measurements, I find it useful when the fundamental wave is too close to the scale that you can simply move the label to the other side.

[woody]

[There is already a snap function. When using a mouse, you can click and drag a channel marker or the trigger position marker with the right mouse button. The level or time position will then snap to fifth-of-a-div steps.

For touchscreen operation, this works by using a second finger. First, touch and drag the channel or trigger marker with one finger. Then place a second finger on the screen, and the movement will snap to fifth-of-a-div steps.

I cannot get my head (or fingers) around how to make this happen with the touch screen, but using the right mouse button this works great. Nice feature to manage my OCD!

[ralphrmartin]

My suggestion for the horizontal axis:
1. get rid of the "s" in the units -> that's a redundant information
2. use the same unit for all the values -> change "800u" into "0.8m" if all other values are in "m"
3. center the values to the grid
4. add the values at the top of the grid or at the bottom, not on both edges
5. maybe mark only every second grid -> that should be enough

I disagree with the 4th point. It is handy to have the values above or below, depending on where the trace is on the screen, but I dont want them to jump up and down as I move the trace. So having both is best I think.

As for the first point, I also prefer to see the units (s).

As André says, some of these are personal preferences...

[MikeP]

 Please show me a screenshot of the FFT for a frequency of 5 MHz and a minimum RBW.
 Thanks.

[Martin72]

??

More details please...

[rf-messkopf]

Please show me a screenshot of the FFT for a frequency of 5 MHz and a minimum RBW.
 Thanks.

When I want to display a signal at 5 MHz, I need the effective sampling rate of the FFT after decimation to be greater than 10 MSa/s. With a the FFT length set to maximum (i.e., 8 Mpts) I can get the RBW as low as 2.24 Hz.

Is it that what you are looking for?

If you want a lower RBW you could export more than 8 Mpts to a PC and do the FFT offline.

[MikeP]

 Thank you very much. I'll probably have to create a filter with high rectangularity. If I remember correctly, the bandwidth is around 4 kHz. I don't want to buy a SA/VNA for this task. Magnova can solve this problem.
 By the way, a question for the Magnova team. Have you considered using software or hardware implementation of algorithms similar to Spectra View from Tektronix?

[Andre77]

By the way, a question for the Magnova team. Have you considered using software or hardware implementation of algorithms similar to Spectra View from Tektronix?

Thank you very much for your inquiry, Mike!

If you're looking for an FFT view that behaves largely independent of the time-domain settings, there's a configuration on the Magnova that gets you quite close.

When you set the FFT gate to “Memory” and choose a fixed acquisition length, the FFT processes the full captured dataset instead of whatever is currently shown in the time domain. This means you can change the time base for the waveform display without shifting or compressing the spectrum.

You can still use the zoom function as well, but the “Memory” gate with a fixed memory depth is the key if you want a spectrum view that stays stable while you browse around in the time domain.

I’ve recorded a short demo video to illustrate this. In the first 10 seconds, I change the time-domain settings without using the above configuration, so you can clearly see the FFT reacting. Afterwards, with a fixed memory depth (5 Mpts in the video) and the FFT gate set to Memory, you can scale the time-domain view over a wide range without affecting the FFT display.

[youtube][/youtube]

[Xyphro]

Hi,

just want to share a finding + workaround to save others time.

I wanted to readout Waveform data from Magnova over USB and it did not work (tracked down to the root cause and informed Batronix who picked it up nicely for addressing it by SW guys). At least with Windows, high speed USB connection and using a VISA which uses a read buffer increment size of a multiple of the bulk in endpoint size (512 for hs) it did simply not work.

In case you run into timeout issues when using e.g.:
data = scope.query_binary_values(’CHAN1:DATA:PACK? ALL,RAW’, datatype=’B’) # taken from MAgnova SCPI manual


Do this:
scope.write('CHAN1:DATA:PACK? ALL,RAW')
charcount = int(scope.read_bytes(2)[1])-ord('0')
bytecount = int(scope.read_bytes(charcount))
print('bytecount: %d' % bytecount)
done = False
MAXCHUNKSIZE = 512-12-1 # USBTMC experts will immediately see why this makes it work :-)
data = b''
while not done:
    chunklen = bytecount
    if chunklen > MAXCHUNKSIZE:
        chunklen = MAXCHUNKSIZE
    data += scope.read_bytes( chunklen )
    print(len(data))
    bytecount -= chunklen
    done = chunklen <= 0

And it will work.

Best regards,

Kai
Update: made it more general, the workaround can be further optimized of course, but I am unblocked with that simple approach.

Update 19th January: that workaround is not required anymore for fw version 1.7.2, the ZLP is now sent by the scope, tested it succesfully!

[blackdog]

Hi, 

Today, my 350MHz Magnova Scoop with function generator module arrived.

I'm not entirely sure, but does this scoop already support a web interface?
I don't think so, as I tried to connect to the scoop's IP address on these ports: 80, 8080 and 443.
This was via http and https.

My goal is not so much to operate the instrument via a web interface, but mainly for screenshots.
At the moment, I use the Quick Save function via SMB for this.
But sometimes it's easier, when I'm sitting with my back to the scope, to be able to adjust some settings on the scope via the web interface.

I've already searched for this function, but that meant I had to install Python, if I understood correctly.
I prefer not to use any extra software to keep my workstation as clean as possible.

So, is control via a normal browser already available and, if it has not yet been implemented, how do I connect and when will it be available?

Thanks and best regards,
Bram

[Martin72]

Hi,

I'm not entirely sure, but does this scoop already support a web interface?

Not at the moment, which is one of the few negative points about the Magnova Scope—at least for me.

[Xyphro]

With root access we could certainly do that quickly if visa is exposed via loopback interface. Did not try ssh yet, is it accessible, maybe even a login/pwd documented officially?
At least something simple in the beginning would be easy to do. A hardcopy button, trace download and as stretch goal VNC for live view :-)

Edit: Already just a vnc server would be great and enable a lot of things.

[blackdog]

Hi, 

Thanks Martin72!

Hi Xyphro
Your remarks go a little to far for my, i wil wait on Batronix for this function.
The Samba share works OK for know.
Thanks!

Kind regards,
Bram