Author Topic: "MSO" vs DSO + Logic Analyzer - One More Time  (Read 12098 times)

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Offline Electro Fan

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"MSO" vs DSO + Logic Analyzer - One More Time
« on: May 05, 2013, 03:06:25 am »
Ok, I know, "search the forum, search Google, search more".  I have tried to search everywhere, but I'm still trying to figure out the best way to go:  a DSO and a Logic Analyzer or a "MSO".

And I'm still stuck on "I don't know what I don't know."

So, here is another try:

Is there anyone out there with a Rigol DS1102D or a DS1052D and an Intronix LogicPort who can talk to the relative strengths of the Rigol built-in LA vs. those of the LogicPort?  If not, is there anyone out there with a Rigol 1000D series and a LA simlar to the Intronix LogicPort, or an Intronix LogicPort and something similar to a Rigol 1000D series scope?

I'm trying to figure out what I'd be missing with a Rigol 1000D class scope vs. a LA in the Intronix LogicPort class (or vice versa).  What I really want is the ability to see the analog wave forms and the digital signals sycnhronized on the same screen.  If this can be only done with a "MSO" then so be it.  On the other hand, if this can be done with some combination of a scope and seperate LA with some combination of trigger outs and trigger ins, that might be good also.

I just want to figure out a decent entry level to see the relationship between voltage induced sine waves and the corresponding bits.  My main use for a while will be Arduino Unos which means relative low clock cycles / low bandwidth requirements.  I don't think I will be looking for rare glitches arcoss humongously long periods of time.  I think I will be initially working with SPI and I2C so I only need some basic protocol analyzer functions for starters.  What I will graduate to next, you folks here have a better idea than me.

Any reason not to just buy a Rigol DS1052D or a DS1102D and get it over with?  Or is there some reason to buy a Rigol 2072 and an Intronix LogicPort, or is it a futile to think something useful can be accomplished with less than an Aglient 3000 series MSO, or is there something else along these lines that should be considered?

Thanks for any advice.
 

Offline free_electron

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Re: "MSO" vs DSO + Logic Analyzer - One More Time
« Reply #1 on: May 05, 2013, 03:59:31 am »
' digital signals sycnhronized on the same screen.'

then you need an MSO or a combination of an DSO/Logic analyser.

Even though the logicport is a step above the average bitstreamers like Salae , usbee or 'logic' it is still not a true logic analyser with state and timing analysis or tracing capabilities. Now, neither is that rigol thingie...

I would look for a used 54645D mso scope... or a54622D ( the'D') is key. these things are really good MSO's. a step up is the 2000/3000/4000 /6000/7000 series from agilent.

For real heavy lifting you need a real logic analyser. these machines have capabilities that outstrip any MSO ( in terms of reverse assembly, source tracing and state decoding/triggering ) . a real analyser can by synced to a scope and pull in the data.
My 16702B talks to my infiniuum scope over the network and pulls in data to show in sync on the same screen. it has a special time align box to calibrate the timing between machines. there are even scope cards that plug into the analyser directly.

You can often find used 167xx on ebay for 200 to 300$. Hook up an lcd monitor and keyboard and off you go. these machines have a PA-Risc processor running HP-UX as operating system. the user interface is an X-host. you can even connect from your PC and use the PC as X-server.
Depending on what you need you pick the 'blades'. The main chassis holds 5 and there is an expansion chassis that can hold another 5.
i have even a pattern generator in mine so i can not only measure but also generate, record and play back signals.

16700 : base machine : external monitor 1024x786 needed.  . 10 mbit lan
option 003 : add graphics memory to pump to 1600x1200
16702a : same machine but with builtin monitor ( 800x600) and keyboard  . external cd drive needed for software update (scsi). 100 mbit lan
16702b : 1024x768 touchscreen , built in cd drive ( scsi). 100 mbit lan and webserver

all machines can run a standard vga screen in 1600x1200

the user interface looks like windows 3.11 but is HP-UX.

latest software is free for these machines. get it from agilent ftp site, burn image on cdrom and boot the installer.

the machine has a 10 gigabyte scsi drive. the hp-ux kernel sits in flash rom so you can't brick this unix. only the X environment and application is loaded from harddisk. even if you fry the harddisk you can still boot into hpux and launch the installer.



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Offline Electro Fan

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Re: "MSO" vs DSO + Logic Analyzer - One More Time
« Reply #2 on: May 05, 2013, 04:24:07 am »
' Even though the logicport is a step above the average bitstreamers like Salae , usbee or 'logic' it is still not a true logic analyser with state and timing analysis or tracing capabilities.

On the Intronix site it says:

Timing mode sample rate: 1KHz to 500MHz (uses internal clock)
State mode sample rate: 0 to 200MHz (clock provided by circuit under test)


- they seem to think their product supports both timing mode and state mode, no?
 

Online nctnico

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Re: "MSO" vs DSO + Logic Analyzer - One More Time
« Reply #3 on: May 05, 2013, 08:35:46 am »
IMHO you are better of with an MSO. An MSO covers about 99% of what you'd use a logic analyser for. I can't recommend the Logicport due to its short memory (even with 'compression').
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline djsb

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Re: "MSO" vs DSO + Logic Analyzer - One More Time
« Reply #4 on: May 05, 2013, 09:33:16 am »
' digital signals sycnhronized on the same screen.'

then you need an MSO or a combination of an DSO/Logic analyser.

Even though the logicport is a step above the average bitstreamers like Salae , usbee or 'logic' it is still not a true logic analyser with state and timing analysis or tracing capabilities. Now, neither is that rigol thingie...

I would look for a used 54645D mso scope... or a54622D ( the'D') is key. these things are really good MSO's. a step up is the 2000/3000/4000 /6000/7000 series from agilent.

For real heavy lifting you need a real logic analyser. these machines have capabilities that outstrip any MSO ( in terms of reverse assembly, source tracing and state decoding/triggering ) . a real analyser can by synced to a scope and pull in the data.
My 16702B talks to my infiniuum scope over the network and pulls in data to show in sync on the same screen. it has a special time align box to calibrate the timing between machines. there are even scope cards that plug into the analyser directly.

You can often find used 167xx on ebay for 200 to 300$. Hook up an lcd monitor and keyboard and off you go. these machines have a PA-Risc processor running HP-UX as operating system. the user interface is an X-host. you can even connect from your PC and use the PC as X-server.
Depending on what you need you pick the 'blades'. The main chassis holds 5 and there is an expansion chassis that can hold another 5.
i have even a pattern generator in mine so i can not only measure but also generate, record and play back signals.

16700 : base machine : external monitor 1024x786 needed.  . 10 mbit lan
option 003 : add graphics memory to pump to 1600x1200
16702a : same machine but with builtin monitor ( 800x600) and keyboard  . external cd drive needed for software update (scsi). 100 mbit lan
16702b : 1024x768 touchscreen , built in cd drive ( scsi). 100 mbit lan and webserver

all machines can run a standard vga screen in 1600x1200

the user interface looks like windows 3.11 but is HP-UX.

latest software is free for these machines. get it from agilent ftp site, burn image on cdrom and boot the installer.

the machine has a 10 gigabyte scsi drive. the hp-ux kernel sits in flash rom so you can't brick this unix. only the X environment and application is loaded from harddisk. even if you fry the harddisk you can still boot into hpux and launch the installer.

Is it feasible to still buy parts to repair these? There is at least one on Ebay that is faulty (one listed as power supply fault).
Do you have any tips on what to look out for or avoid when buying. Any user or service manual available anywhere (I'm guessing Agilent will have them for download?)

David.
David
Hertfordshire,UK
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Offline jpb

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Re: "MSO" vs DSO + Logic Analyzer - One More Time
« Reply #5 on: May 05, 2013, 12:36:06 pm »
I think that this is not just a technical question.

Other issues are budget and physical space and convenience.

I am facing the same question but don't yet have an immediate need so have not yet invested in a logic analyser though I have
made my choice as I've got a non-MSO scope. I reckoned that getting 4 channels and higher bandwidth (350MHz) was a better
use of my budget than a more basic scope with the option of 8 digital channels.

But in my case, my budget didn't extend to the MSOX3000 series when I bought my scope and other decent MSOs are even more expensive.

Below this level MSOs seem pretty basic but still pricey compared to non-MSO equivalents. The Hameg scopes seem to offer quite good value
but all MSOs at the lower price levels are restricted to 8 channels though I guess this covers all serial comms. Stand alone logic analysers off e-bay seem to be
potentially powerful but rather large physically, I couldn't make bench space for one but you might have a lot more room.

I often suffer from paralysis by analysis and I suspect that you have a similar approach to problems. The real decision is are you going to try and get all
your tools in one box or put up with the inconvenience of having a collection of tools.

The cost of the LogicPort is $380, the cost of a cheap Rigol scope is $350 the cost of a MSOX2000 with 4 channels and 8 digital channels is around $3000
the cost of the most basic MSOX3000 with 4 channels is getting on $4000. (Of course you can get cheaper prices on e-bay from time to time.)

So if you go for the LogicPort and basic Rigol then you can learn what you really need and even if you sell them on at half price the cost is only going to be
around $300. More likely you'll just upgrade the scope and keep the logicport for some purposes even if you add an option with more memory.

If on the other hand you go for the MSOX2000, pay extra for decoding options and at the end of the day feel you need the MSOX3000 and have to trade up
the cost will probably be nearer $2000.

It seems to me that you (like me) don't quite know what your real needs and wants will be so I'd go for the cheapest means of finding out rather than
invest a lot of money in a very expensive tool that will cover all potential needs but ends up having most of its features left unused.
 

Offline free_electron

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Re: "MSO" vs DSO + Logic Analyzer - One More Time
« Reply #6 on: May 05, 2013, 03:00:21 pm »


Is it feasible to still buy parts to repair these? There is at least one on Ebay that is faulty (one listed as power supply fault).
Do you have any tips on what to look out for or avoid when buying. Any user or service manual available anywhere (I'm guessing Agilent will have them for download?)

David.
There are no schematics. There is a module level manual. Anyway there is not much in these machines. The power supply is a big honking switcher. There is the computer board which is a full custom design using a pa-risc processor. The memory is soldered in. Option 03 is a special custom board that slots in as well. Then there is the backplane and a couple of scsi connectors.
Like i said , hpux is stored in flash rom. If the harddisk is dead you can still boot to command line.

Agilent has a document on how to replace the harddisk. Any scsi-1 drive of about 2 to 20 gig will work fine. Hpux has a command script to partitionthe drive automatically ( the create two partitions. One for the analyser software, the other is userdata. They need specicif names and be mounted in specific paths bit the script takes care of that. The disk init takes like 1 minute.)
After that you hook up an external scsi cdrom( i used one from sun in an external housing ). They need to be set to channel 7. Pop in the cd and revoot the chassis. It will autodetect the cd and ask you what you want to do
- update analyser software
- update hpux
- update all

Just launch the last option

It will copy the hpux files first to harddisk , verify integrity and then reflash. So it cant really go wrong ( unless you have a power interrupt )

Also the main power button is a soft power button signalling the kernel it needs to stop. It will sync everything to disk before telling you you can push the button again to power off.

They are heavy big machines but the nice thing is that they are modular. You can mix and match cards. Sometimes you can find really good deals on these things. I got mine for 400$ and it came with three blades sporting 68 channels at 4Ghz each..
« Last Edit: May 05, 2013, 03:10:16 pm by free_electron »
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Online nctnico

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Re: "MSO" vs DSO + Logic Analyzer - One More Time
« Reply #7 on: May 05, 2013, 05:01:21 pm »
How about the noise? I used to have a Tektronix DAS9200 logic analyses system which was pretty noisy.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline Electro Fan

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Re: "MSO" vs DSO + Logic Analyzer - One More Time
« Reply #8 on: May 05, 2013, 06:17:25 pm »
I think that this is not just a technical question.

Other issues are budget and physical space and convenience.

I am facing the same question but don't yet have an immediate need so have not yet invested in a logic analyser though I have
made my choice as I've got a non-MSO scope. I reckoned that getting 4 channels and higher bandwidth (350MHz) was a better
use of my budget than a more basic scope with the option of 8 digital channels.

But in my case, my budget didn't extend to the MSOX3000 series when I bought my scope and other decent MSOs are even more expensive.

Below this level MSOs seem pretty basic but still pricey compared to non-MSO equivalents. The Hameg scopes seem to offer quite good value
but all MSOs at the lower price levels are restricted to 8 channels though I guess this covers all serial comms. Stand alone logic analysers off e-bay seem to be
potentially powerful but rather large physically, I couldn't make bench space for one but you might have a lot more room.

I often suffer from paralysis by analysis and I suspect that you have a similar approach to problems. The real decision is are you going to try and get all
your tools in one box or put up with the inconvenience of having a collection of tools.

The cost of the LogicPort is $380, the cost of a cheap Rigol scope is $350 the cost of a MSOX2000 with 4 channels and 8 digital channels is around $3000
the cost of the most basic MSOX3000 with 4 channels is getting on $4000. (Of course you can get cheaper prices on e-bay from time to time.)

So if you go for the LogicPort and basic Rigol then you can learn what you really need and even if you sell them on at half price the cost is only going to be
around $300. More likely you'll just upgrade the scope and keep the logicport for some purposes even if you add an option with more memory.

If on the other hand you go for the MSOX2000, pay extra for decoding options and at the end of the day feel you need the MSOX3000 and have to trade up
the cost will probably be nearer $2000.

It seems to me that you (like me) don't quite know what your real needs and wants will be so I'd go for the cheapest means of finding out rather than
invest a lot of money in a very expensive tool that will cover all potential needs but ends up having most of its features left unused.

Hi jpb,

Thanks for the thoughtful reply.

I believe you are correct - the choice is some combination of scope plus LA in the $1k and under range or jump up to the $2k-$3k and beyond range.  So, it's probably more practical/wise to get some experience, and if need be salvage some of the first investment and move up when and if needed.

So, that brings up a few choices:

1. a DS1052D or a DS1102D
2. live with my Tektronix 2247A and add an Intronix LogicPort for about $389 (or try to save some $ and go with a Saleae in the $149-$299 range)
3. maybe go with a DS1052e or DS1102E and one of the LAs

What I really want to accomplish is to simply see analog waveforms and the digital signals at the same time on the same screen synchronized together.

Clearly, I am at the beginning stages.  Here are two examples of the very simple stuff I'd like to do:

I have an Arduino Uno.  I can make the onboard LED blink at various intervals by changing the sketch code parameters for the length of time the LED is on and the length of time the LED is off.  I've added a LCD display that taps into the circuit and I can watch the voltage rise to 5 volts and lower to 0 volts as the LED blinks.   With a scope I'd like to see the voltage rise and decline while on the same screen I'd like to see the correlated 1s and 0s.

In another super simple project I can turn three potentiometers to adjust the amounts and mix of RGB colors on a RGB LED.  In the software monitor I can see the values for each color move between 0 and 1023.  With a scope I'd like to the voltage change and with the LA I'd like to see the digital signals and their values - but I'd like to see both the analog and the digital signals on the same screen syncrhonized in time.

Of course, I'd like to be able to do some reasonable amount of triggering for both the analog and digital signals and look at the results on one screen.  And I'd like to be able to have basic decode support for I2C and SPI.

I'm pretty sure that even the Saleae entry level unit can show such digital signal logic analysis and I'm confident the Intronix LogicPort can do much more, but what I don't know/understand is:

1) is there is a way to get the digital signals from one of these LAs AND ALSO the analog signals from the Tektronix 2247A to appear SIMULTANTEOUSLY AND IN A SYCNCHRONIZED MANER on my computer screen? 

2) If the Tektronix 2247A can't output a signal that can be displayed on my computer screen along with the LA signals, would a DS1052E or a DS1102E have the ability to simultanteously send synchronized analog signals to the computer screen?

3) Alternatively, maybe it would be easier and not much more $ to do this sort of thing with the DS1052D or DS1102D (using their built in LAs)?


Any answers or comments on these specific questions would be very much appreciated.

Thanks!
« Last Edit: May 05, 2013, 06:59:36 pm by Electro Fan »
 

Offline free_electron

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Re: "MSO" vs DSO + Logic Analyzer - One More Time
« Reply #9 on: May 05, 2013, 06:38:12 pm »
How about the noise? I used to have a Tektronix DAS9200 logic analyses system which was pretty noisy.

reasonably quiet. no more than a desktop pc.
the 1670x has 4 huge slow running fans on the side. it's not a bunch of whiney mosquito fans ( i know the tektronix das machines. my god... wheeeeeeeee )
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Offline marmad

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Re: "MSO" vs DSO + Logic Analyzer - One More Time
« Reply #10 on: May 05, 2013, 08:03:03 pm »
1) is there is a way to get the digital signals from one of these LAs AND ALSO the analog signals from the Tektronix 2247A to appear SIMULTANTEOUSLY AND IN A SYCNCHRONIZED MANER on my computer screen?

Not very easily in real-time. Not only will you have to deal with display jitter due to timing misalignment, but you'll have to deal with transfer speeds to the PC - and then issues caused by two different pieces of computer software vying for resources (how does the Tek connect to the PC? Via GPIB?). But I don't understand why it has to be one screen? Synchronizing the two isn't a problem - but trying to move both outputs to one display will certainly create new problems to solve.

When I'm using both scope and LA, I just have the oscilloscope parked next to the computer monitor - as if it's an extension of the bigger screen. I prefer it that way because you're normally looking at detail with the scope - so having it's own screen and set of control knobs is a benefit instead of a hindrance. Is it a space issue?

Quote
2) If the Tektronix 2247A can't output a signal that can be displayed on my computer screen along with the LA signals, would a DS1052E or a DS1102E have the ability to simultanteously send synchronized analog signals to the computer screen?

Again, it's possible - you'll just have a bunch of timing issues to deal with (same as #1 above).

Quote
3) Alternatively, maybe it would be easier and not much more $ to do this sort of thing with the DS1052D or DS1102D (using their built in LAs)?[/b]

Well, it's always easier with an MSO - that's the reason people buy them; but it's certainly not cheaper (and you normally get many less features for quite a bit more money). And, IMO, once you've figured out your setup for DSO + LA once, it's pretty easy from them on. To that end, I hope to make a video about it in the coming week or so - to help other's out.
« Last Edit: May 05, 2013, 08:09:20 pm by marmad »
 

Offline jpb

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Re: "MSO" vs DSO + Logic Analyzer - One More Time
« Reply #11 on: May 05, 2013, 08:29:58 pm »

1) is there is a way to get the digital signals from one of these LAs AND ALSO the analog signals from the Tektronix 2247A to appear SIMULTANTEOUSLY AND IN A SYCNCHRONIZED MANER on my computer screen? 

2) If the Tektronix 2247A can't output a signal that can be displayed on my computer screen along with the LA signals, would a DS1052E or a DS1102E have the ability to simultanteously send synchronized analog signals to the computer screen?

3) Alternatively, maybe it would be easier and not much more $ to do this sort of thing with the DS1052D or DS1102D (using their built in LAs)?


Any answers or comments on these specific questions would be very much appreciated.

Thanks!
I don't think the Trektronix can provide any data output as it is an analogue scope? (Unless you take pictures with a digital camera :))

Taking a quick look at the Rigol manual it looks as if you can save csv files but there is no easy way to control via usb or lan. This means that you could do what you want but it would need to be all manual.

The main issue is triggering both the LA and the scope. The best solution is to trigger both from the same source then there is no issue with trigger delay.

The next best is to use the trigger out of the LA (if you make sure you order a LA with trigger out) to trigger the scope. There then will be a delay which will need to be accounted for. You may need to do some experimentation to find out what the delay is, it is likely to be around 100nsecs (this is the figure I was given by LeCroy for their LogicStudio).

Since both the LA and the scope can produce csv files the rather tedious manual procedure I guess would be to read them both into a spreadsheet, subtract the trigger delay from all the scope time values and then do the plots.

Better would be to write some software to do it.

Looking at the Rigol manual for the DS1000D series, the trigger options are very limited. It can show digital and analogue signals on the same scope but you'd need to generate simple trigger signals. This might be the best option but you'll probably need to add extra circuitry or do extra programming on your circuits.

maybe something like the PicoScope 2205 will do what you want at a reasonable price, it will display everything on the pc and has advanced triggering decoding etc.
The analogue signals are limited to 25MHz but this might be good enough for your circuits given that you can use the Tektronix if you want higher bandwidth on occasion.
It sounds expensive from the hardware specs but you're really paying for the software which I think is pretty good.

http://www.picotech.com/mixed-signal-oscilloscope.html
« Last Edit: May 05, 2013, 08:40:40 pm by jpb »
 

Offline Electro Fan

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Re: "MSO" vs DSO + Logic Analyzer - One More Time
« Reply #12 on: May 05, 2013, 08:41:52 pm »
1) is there is a way to get the digital signals from one of these LAs AND ALSO the analog signals from the Tektronix 2247A to appear SIMULTANTEOUSLY AND IN A SYCNCHRONIZED MANER on my computer screen?

Not very easily in real-time. Not only will you have to deal with display jitter due to timing misalignment, but you'll have to deal with transfer speeds to the PC - and then issues caused by two different pieces of computer software vying for resources (how does the Tek connect to the PC? Via GPIB?). But I don't understand why it has to be one screen? Synchronizing the two isn't a problem - but trying to move both outputs to one display will certainly create new problems to solve.

When I'm using both scope and LA, I just have the oscilloscope parked next to the computer monitor - as if it's an extension of the bigger screen. I prefer it that way because you're normally looking at detail with the scope - so having it's own screen and set of control knobs is a benefit instead of a hindrance. Is it a space issue?

Quote
2) If the Tektronix 2247A can't output a signal that can be displayed on my computer screen along with the LA signals, would a DS1052E or a DS1102E have the ability to simultanteously send synchronized analog signals to the computer screen?

Again, it's possible - you'll just have a bunch of timing issues to deal with (same as #1 above).

Quote
3) Alternatively, maybe it would be easier and not much more $ to do this sort of thing with the DS1052D or DS1102D (using their built in LAs)?[/b]

Well, it's always easier with an MSO - that's the reason people buy them; but it's certainly not cheaper (and you normally get many less features for quite a bit more money). And, IMO, once you've figured out your setup for DSO + LA once, it's pretty easy from them on. To that end, I hope to make a video about it in the coming week or so - to help other's out.

Thanks and I'm definitely up for seeing your upcoming video!

It's not so much a space thing (although space is a medium size practical consideration), it's more about this notion of not having to deal with the timing issues you cite and still being able to have one screen show the time alignment between the analog and digital signals.  I could be wrong about the utility of this - especially for more intermediate and advanced users - but I have this theory that says my learning curve will be easier/more enjoyable if I can say - "right there - there is the analog wave form and there right below it is the digital signal; this is where some voltage level turned into a one or a zero."  Once I gain confidence I can see it in simple cases I can move on to more complex cases.

As for the price, it seems like even a DS1102E at $400 plus a Saleae entry level device at $150 makes the full entry level about $550.  With a DS1102D the price is somewhere between $715 (not sure if this is really doable) and $900.  I'm not clear on how the $150 Saleae stacks up against the internal LA in the DS1102D (any comments on this would be very welcome).

(I think a used DS1102D might be a great option if there is one out there for sale.)

Thanks again for any questions, suggestions, and guidance.
 

Offline marmad

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Re: "MSO" vs DSO + Logic Analyzer - One More Time
« Reply #13 on: May 05, 2013, 08:55:13 pm »
Taking a quick look at the Rigol manual it looks as if you can save csv files but there is no easy way to control via usb or lan. This means that you could do what you want but it would need to be all manual.

Of course you can - you can grab the display via SCPI commands over USB - the bigger problems are the things I mentioned in my previous post.

Quote
The best solution is to trigger both from the same source then there is no issue with trigger delay.

I don't think you've actually done this, have you?   ;)  You will still have display jitter - that's why you need to do cross-triggering with a qualifier.

Quote
The next best is to use the trigger out of the LA (if you make sure you order a LA with trigger out) to trigger the scope. There then will be a delay which will need to be accounted for. You may need to do some experimentation to find out what the delay is, it is likely to be around 100nsecs (this is the figure I was given by LeCroy for their LogicStudio).

To do it right, you always need a trigger out - it doesn't matter if it's from the LA or the DSO, but whichever is the one that has trigger out is the qualifier. Most people prefer it to be the LA since it usually has more trigger possibilities, although modern DSOs (like the DS2000) have quite a lot as well. The best of both worlds is if you have both a DSO and LA with trigger out - so that you can hook them up either way. I use my DSO's trigger out since I don't currently have an LA with one.

Quote
Since both the LA and the scope can produce csv files the rather tedious manual procedure I guess would be to read them both into a spreadsheet, subtract the trigger delay from all the scope time values and then do the plots.

Hmm... tedious would be a nice way to describe this process  ;D


Edit: One thing I forgot to mention - if you don't have a trigger out on the LA, then you can't (as easily) use it with the DSO in Timing mode (as opposed to State mode).
« Last Edit: May 05, 2013, 09:18:43 pm by marmad »
 

Offline marmad

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Re: "MSO" vs DSO + Logic Analyzer - One More Time
« Reply #14 on: May 05, 2013, 09:12:19 pm »
It's not so much a space thing (although space is a medium size practical consideration), it's more about this notion of not having to deal with the timing issues you cite and still being able to have one screen show the time alignment between the analog and digital signals.  I could be wrong about the utility of this - especially for more intermediate and advanced users - but I have this theory that says my learning curve will be easier/more enjoyable if I can say - "right there - there is the analog wave form and there right below it is the digital signal; this is where some voltage level turned into a one or a zero."  Once I gain confidence I can see it in simple cases I can move on to more complex cases.

Assuming you have either a DSO or LA with trigger out, it's really not difficult at all to align the timings. If you don't, then it's still possible to do, but it's a pain in the ass when changing settings on one of the devices (i.e. time base on the DSO, etc).

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As for the price, it seems like even a DS1102E at $400 plus a Saleae entry level device at $150 makes the full entry level about $550.  With a DS1102D the price is somewhere between $715 (not sure if this is really doable) and $900.  I'm not clear on how the $150 Saleae stacks up against the internal LA in the DS1102D (any comments on this would be very welcome).

I'm guessing that the Saleae has more features than the DS1102D - but I've never looked at the manuals for the Rigol MSOs. The best way to find out is just to look through them online.
 

Offline jpb

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Re: "MSO" vs DSO + Logic Analyzer - One More Time
« Reply #15 on: May 05, 2013, 09:13:53 pm »
Of course you can - you can grab the display via SCPI commands over USB - the bigger problems are the things I mentioned in my previous post.
I don't know the scopes (I have a WaveJet), I knew the 2000 series had all these features but I couldn't see anything in the 1000 series manual.


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The best solution is to trigger both from the same source then there is no issue with trigger delay.

I don't think you've actually done this, have you?   ;)  You will still have display jitter - that's why you need to do cross-triggering with a qualifier.

I have to admit that I haven't, but I would have thought the jitter (or differences in trigger speed/delay) would be less than the trigger delay doing it in series. Of course it matters if you're trying to accurate timing between digital and analogue signals. But I got the impression in this case was just to get the signals close enough so that digital signals can be lined up ok. I presume it all comes down to the time resolution actually needed. Also can't the trigger signal itself be used as a marker on both displays?

« Last Edit: May 05, 2013, 09:15:37 pm by jpb »
 

Offline marmad

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Re: "MSO" vs DSO + Logic Analyzer - One More Time
« Reply #16 on: May 05, 2013, 09:34:15 pm »
I have to admit that I haven't, but I would have thought the jitter (or differences in trigger speed/delay) would be less than the trigger delay doing it in series. Of course it matters if you're trying to accurate timing between digital and analogue signals. But I got the impression in this case was just to get the signals close enough so that digital signals can be lined up ok. I presume it all comes down to the time resolution actually needed. Also can't the trigger signal itself be used as a marker on both displays?

Of course, any of these techniques would be usable to a certain degree - but the ideal is to have the DSO and LA synchronized both with the device-under-test as well as with each other. Just using cross-triggering alone won't have the DSO and LA perfectly synced - and just using the trigger out of one to trigger the other won't have them both synced to the DUT clock. And although you can get it working without doing this, it will be a pain when changing certain settings - whereas if they're all synced correctly, it's not a problem.
 

Offline marshallh

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Re: "MSO" vs DSO + Logic Analyzer - One More Time
« Reply #17 on: May 05, 2013, 09:43:38 pm »
Friend of mine got a HP 16500 and detailed some of the setup experience here

http://blog.kevtris.org/

They come with DOOM on them, lol.
Verilog tips
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11:37 <@ktemkin> c4757p: marshall has transcended communications media
11:37 <@ktemkin> He speaks protocols directly.
 

Offline Pinkus

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Re: "MSO" vs DSO + Logic Analyzer - One More Time
« Reply #18 on: May 13, 2013, 03:23:42 pm »
I owned a DS1102 and I still own a Logicport.
To be honest: while the scope will be exchanged once in a while (was a Hantek 200 Mhz after the DS1102 and will be a Rigol DS2000 series soon) the Logicport will stay.
Why?
Because it is much much easier and quicker to set up the signals, signal names, trigger, logic level etc. etc on the PC as on the scope.
It is much easier to scroll through your data, set cursors with a mouse click.
You can save and load saved data later to analyze or to compare it to other sampled data (you can open several instances of the Logicport Software for comparision of data).

A benchtop MSO will be nice for a quick check of a handful I2C Data or to check if all lines are working, but I would (and do) always use my Logicport if I know I will have to do some serious stuff which might take longer.

The limited memory of the Logicport (68 KByte or 2KByte per channel) never was a problem as compression and intelligent triggering always helped me to see only that part of the data, I was interested in. If you know what you are doing you usually need just a few ms of data (though the Logicport can sample for hours - given compressable data).

Peter

 

Offline fried chips with wine

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Re: "MSO" vs DSO + Logic Analyzer - One More Time
« Reply #19 on: June 25, 2013, 10:38:25 am »
Hi free electron, can you get me the link to the complete HP-16702b software.
I got one from ebay, probably with broken LCD inverter/CCFL-lamp and I've two nice 128MSa memory 16760A cards for it. Should arrive any day, so I thought I already look for the latest software.

You said, it is on the agilent FTP, but I'm unable/incapable to find it, the agilent FTP has lots of folders with unclear names, so I don't know where to look, if it's even still there.

Thank you

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latest software is free for these machines. get it from agilent ftp site, burn image on cdrom and boot the installer.

 

Offline alank2

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Re: "MSO" vs DSO + Logic Analyzer - One More Time
« Reply #20 on: June 25, 2013, 01:40:28 pm »
I've tried 3 LA's so far:

I have an older series Rigol with their LA (1022CD) and the LA is just ok.  When you go from a running state to stop it seems to move the waveforms on the display slightly to the left or right, I'm not sure why.  It has no decoders on my model, and I'm not sure if the 1052D/1102D have any decoders either which to me is a big deal.  You can set the voltage threshold which is nice and see signals along side analog channels if this is important.

I've tried a saleae clone from iteadstudio.  It is $45 and uses the saleae client.  If you want to try a USB based LA for cheap, this is one way to do it without much investment to see what you think.  The official saleae is much nicer looking and more polished.  You can record forever, but 24MHz sampling rate maximum.  Very polished and easy to use client.  Lots of decoders.  No voltage threshold setting on this model, but saleae has one for $299 that has 16 channels and I think the ability to set a voltage threshold.

I've also tried the dangerousprototypes open bench logic sniffer.  It can go to 200MHz, but uses on board memory so its capture length is very limited.  The client for it is much better than it was, but it still is a bit glitchy for me.  Nice trigger options in the client though.  Many decoders, but some crash the client too easily.  No voltage threshold setting.

If you (1) don't mind spending the $$$, (2) want analog and digital on the same screen, and (3) can get a MSO with the decoders you need, go for that direction.

Of the three I have, I really like the saleae clone.  So much that if I had to do it all over again I would buy the real saleae and just use that unless I needed something higher bandwidth...
 

Offline motocoder

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Re: "MSO" vs DSO + Logic Analyzer - One More Time
« Reply #21 on: August 01, 2013, 06:44:19 pm »
alank2 - does the iteadstudio clone work with the latest Saleae client? I saw some reference that they had found a way to detect that and blocked some of the clones.
 

Offline alank2

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Re: "MSO" vs DSO + Logic Analyzer - One More Time
« Reply #22 on: August 01, 2013, 07:02:27 pm »
alank2 - does the iteadstudio clone work with the latest Saleae client? I saw some reference that they had found a way to detect that and blocked some of the clones.

Yes - I ordered the clone when it first came out so if there are multiple clone versions I probably have an early one.  Mine works with the current 1.1.15 software no sweat.
 

Offline echen1024

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Re: "MSO" vs DSO + Logic Analyzer - One More Time
« Reply #23 on: August 02, 2013, 12:33:18 am »
If you really want analog and digital on the same screen, an MSO is probably your best option. Not sure if the Rigol 2000 series has it, but the Agilent scopes and the Tektronix DPO series both have integrated logic analyzers. With the Agilent, you need to purchase a software code, while the Tek includes 'application modules' which can be reverse engineered, to help you decode serial data.

http://www.tek.com/oscilloscope/mso2000-dpo2000
http://www.home.agilent.com/en/pc-1940892/infiniivision-2000-x-series-oscilloscope?nid=-33575.0&cc=US&lc=eng
I'm not saying we should kill all stupid people. I'm just saying that we should remove all product safety labels and let natural selection do its work.

https://www.youtube.com/user/echen1024
 


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