Author Topic: What Logic analyzer would you recommend (for a sane price)?  (Read 8260 times)

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Offline Pentium100

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Hi, it occurred to me that it would be easier to repair stuff if I had a logic analyzer. However, I do not know which one to choose (and do not have a lot of money to buy a really good expensive one). Maybe you can recommend me one?

My requirements would be:
Price: hopefully no more than $250.
Sampling rate: 100-200MHz probably would be enough, 50MHz or so in state mode (external clock).
Channels: 16 would probably be enough.
Input: Settable threshold and the ability to tolerate negative voltages and higher voltages (at least so I can use it on PMOS logic or RS232 with the proper signal levels and low voltage devices).
Software that can decode a lot of different protocols - I do not know which ones I'll find in some broken device. It also would be good if the software could export the data/waveforms in some format that is easily parsed - in case I need to write the decoder myself.

Any devices that meet or approach these requirements?

Searching in ebay I found Hantek 4032L - the specs are impressive, but as I understand the software is low quality. Anything similar that has good software?
« Last Edit: June 30, 2013, 05:15:45 am by Pentium100 »
 

Offline David_AVD

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Re: What Logic analyzer would you recommend (for a sane price)?
« Reply #1 on: June 30, 2013, 08:02:04 am »
Whenever I need to decode RS232 or RS485 lines with an analyser, I use a separate little box to convert to 5V levels.  That way I can use the same overall interface for those and 5V lines at the same time.
 

Online kripton2035

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Re: What Logic analyzer would you recommend (for a sane price)?
« Reply #2 on: June 30, 2013, 08:28:30 am »
try yourself with an openlogic sniffer
http://www.seeedstudio.com/depot/open-workbench-logic-sniffer-p-612.html?cPath=63_69
it's cheap $50 and powerfull enought and decodes a lot of things and is open source so you can add yours.
then if it's not enought for certain needs, you can buy a stronger one ?
 

Offline amyk

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Re: What Logic analyzer would you recommend (for a sane price)?
« Reply #3 on: June 30, 2013, 10:08:36 am »
Maybe an old HP or similar?
 

Offline Carrington

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Re: What Logic analyzer would you recommend (for a sane price)?
« Reply #4 on: June 30, 2013, 12:24:58 pm »
Do you like this this?
http://www.asix.net/tools/dbg_sigma.htm

But not have support for settable threshold and higher voltages.

See this other but I do not recommend, I have it and does not work very well.:
http://www.aliexpress.com/store/product/LWLA2034-logic-analyzer-200m-30road-quantity-of-state-acquisition-threshold-adjustable-support-external-clock-FREE-SHIPPING/811021_708901546.html



Here you have a good list:
http://sigrok.org/wiki/Supported_hardware#Logic_analyzers
« Last Edit: June 30, 2013, 12:35:06 pm by Carrington »
My English can be pretty bad, so suggestions are welcome. ;)
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Offline free_electron

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Re: What Logic analyzer would you recommend (for a sane price)?
« Reply #5 on: June 30, 2013, 01:54:38 pm »
Maybe an old HP or similar?

yep. thats a real analyser !

now, you say to repair stuff.  logic analysers are typically used to find bugs in a system during design.

for repair ? unless you have known good pattern traces .... you aint going to do much with the LA
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Offline Fraser

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Re: What Logic analyzer would you recommend (for a sane price)?
« Reply #6 on: June 30, 2013, 02:50:38 pm »
I bow to greater knowledge but I bought a logic analyser specifically to investigate a fault on a M68K embedded board.

I needed to be able to see all the address, data and error lines on the board at the same time to see what was causing a 'HALT' exception on the processor. It would appear to me that having a 32CH logic analyser gives a better view of a microprocessor PCB than jumping around with a scope or logic probe. I do have several HP LogicDart's but with only 3 channels each it seemed daft to use them on a 16 bit bus.

I bought a Hantek 4032L and I am pleased with what it has to offer me by way of bus visibility. Stuck bits would be easily spotted and the HALT on the MC68K stops changes to the busses so I should be able to correlate a set of events with the HALT event. Most likely a dual bus error (BERR) event. I can then step along the bus looking for the IC that should have handled the request for action and did not respond correctly.

This is all theoretical as I have yet to find a decent amount of free time to get stuck into the problem. The 'Patient' is a $10k FLIR thermal cameras high density PCB's and access to the various areas of the MCU pcb is made challenging by the stacking of other essential PCB's on it.

The Hantek cost me ~$200 and, for a repair tech, it appears more than capable of the task and very useful. A bit like having a 32 channel oscilloscope with 400Ms/s sampling rate. Of course the scope is still needed to track down logic level errors or noise on logic busses. As a side note, a new PCB for my FLIR is US$4000 + it must be loaded with firmware and calibrated...read oodles of money to replace  :scared:  Repair is the only viable option for me. A classic case of buying the right tool for the job rather than struggling with basic tools and risking failure. $200 is reasonable and I will have future use of the LA I am sure. I also purchased the Hantek 1025G to act as a logic stimulator when required. Finaly I added the ultra cheap Hantek 6022BE 48MS/s DSO as a low freq USB scope to check power rails etc. Hantek has some issues with software quality but it will meet my humble needs and I now have a complete logic investigation kit running on my laptop when needed, and for not a lot of investment.
« Last Edit: June 30, 2013, 03:02:22 pm by Aurora »
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Offline Pentium100

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Re: What Logic analyzer would you recommend (for a sane price)?
« Reply #7 on: June 30, 2013, 03:00:23 pm »
Maybe an old HP or similar?

yep. thats a real analyser !

now, you say to repair stuff.  logic analysers are typically used to find bugs in a system during design.

for repair ? unless you have known good pattern traces .... you aint going to do much with the LA
It sometimes would be useful to sniff communications between chips - assuming I have the datasheet for one of the chips. Then I could figure out if that is OK or not and to inject my values if needed. It would have been useful when I was repairing a server power supply - it took me a while to figure out how to turn it on outside of the server - LA would have made this easier (connect to a server, record the signals, figure them out, program an arduino to replay what I need).

That HP LA seems too good to be true. Is there any catch with it (other than that the shipping cost would be another $200 probably)?

Whenever I need to decode RS232 or RS485 lines with an analyser, I use a separate little box to convert to 5V levels.  That way I can use the same overall interface for those and 5V lines at the same time.
Yes, but not only RS232 uses higher voltages - for example, I have this old calculator (that for some reason does not divide) and it uses 0V and -12V logic levels. It would be better if I could hook up the LA directly.
« Last Edit: June 30, 2013, 06:03:36 pm by Pentium100 »
 

Offline Fraser

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Re: What Logic analyzer would you recommend (for a sane price)?
« Reply #8 on: June 30, 2013, 03:08:57 pm »
YEP, one huge catch for newbies to the old LA marketplace.

If the sale does not include the Logic Pods.....walk away  ;) I see no mention or picture of any pods with that HP LA. Walk away.

An older generation LA that requires logic pods is a paperweight without them and they can be expensive to source separately. You should always look to buy an older LA complete with all its logic pods, and any OS software that should come with it. Without these it can be a VERY disappointing purchase. That was why I ended up going for the Hantek offering. It also saved a massive amount of weight and desk space !

The older LA's can be a challenge to configure for newbies to them and you have to ask yourself whether you are doing repairs or development work. The latter is a far more demanding scenario but repair work rarely need the advanced capabilities and masses of channels.

It sounds like your needs are similar to mine. It is well worth considering the various USB LA's that are available for the less demanding tasks that you and I will likely meet in the world of repair.
« Last Edit: June 30, 2013, 03:13:19 pm by Aurora »
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Offline Carrington

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Re: What Logic analyzer would you recommend (for a sane price)?
« Reply #9 on: June 30, 2013, 05:24:35 pm »
I do not know the price of these, or where they sell. But they look very good.
http://www.embedtools.com/pro_analyser/analyser.asp
The software is great.
My English can be pretty bad, so suggestions are welcome. ;)
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Online nctnico

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Re: What Logic analyzer would you recommend (for a sane price)?
« Reply #10 on: June 30, 2013, 06:31:09 pm »
Maybe an old HP or similar?
IMHO the HP1661A is one worth to investigate further. So far I can see most of them have a LAN connection which may be handy to transfer files or data. Maybe even remote control... There are many for sale on Ebay for very reasonable prices.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline caius

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Re: What Logic analyzer would you recommend (for a sane price)?
« Reply #11 on: July 01, 2013, 08:30:27 pm »
I have an Open Logic Sniffer and I found it pretty good.Obviously it has memory sample limitation and it's not real time.
I'm gonna to buy an old cheap HP logic analyzer but I'm really lost among all  those 16XXX models sold on Ebay.
Could someone suggest me a good one (possibly with integrated oscilloscope)?Thanks.
« Last Edit: July 01, 2013, 08:35:04 pm by caius »
 

Offline free_electron

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Re: What Logic analyzer would you recommend (for a sane price)?
« Reply #12 on: July 01, 2013, 09:39:26 pm »
I do not know the price of these, or where they sell. But they look very good.
http://www.embedtools.com/pro_analyser/analyser.asp
The software is great.
Now that looks like an interesring machine. Is see a bunch of programmable dacs and an array of fast comparators. Which means this thing has true level programming. The big fat fpga probably means that it has some serious triggering as well... I'll have to dig in to this one...
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Offline Fraser

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Re: What Logic analyzer would you recommend (for a sane price)?
« Reply #13 on: July 01, 2013, 10:12:50 pm »
That units little brother , the LA1016, is on ebay and available from Aidetek USA.

http://aidetek.com/mm5/merchant.mvc?Screen=PROD&Store_Code=A&Product_Code=LA1016&Category_Code=Programmer

Taobao has the LA2534 'top of the series' model.

http://item.taobao.com/item.htm?id=8688220638

« Last Edit: July 01, 2013, 10:14:51 pm by Aurora »
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