Choosing a logic analyser  - Page 1
Forum section: electronics / testgear

author: MarkoAnte
author_rank: Regular Contributor
timestamp: May 06, 2014, 10:50:50 pm
content: Hi,I'm thinking of getting a logic analyser for my lab, I'm have been looking at a hp16500b and hp 16702a. They would both for start have the hp 16555a card in them (2x16 channel 500 Mhz/4x16 250 Mhz).I had the 16500b in for a test but I find that my eyes hurt after long work with the analyser. I adjusted all the pots inside so that the colors were back in alignment and I got the thing somewhat focused (after I did the adjustments it was better, but the screen still seemed bad). Tomorrow I should get a 16702A in for a test and a 16500c to compare the screens with.My question is does anybody have experience working with this systems and noticed a bad image quality on the hp 16500b (is this one just bad or is it just the old color crt that are bad quality for today standards). The guy wants 650 euro-ish for the hp 16500b and 850 euro-ish for hp 16702a (with hp16555a, cables, bods, hooks etc. ) I think that based on e bay prices the hp 16702A would be the better choice price wise. What do you thing about pricing (keep in mind that I'm form Slovenia and shipping + taxes would cost a lot)? Is the operating system of the 16702a problematic? Or would it be better to get a pc based analyser? (but I do work with fpgas with fast rate and many channels (32+ - 16 just for adc) and from what I understand ( and have been told) the pc ones slow down if your using all the channels)

author: 0xdeadbeef
author_rank: Super Contributor
timestamp: May 06, 2014, 11:52:11 pm
content: Surprisingly, there are not many "industrial grade" PC based logic analyzers available.About half of them have a relatively small on-board memory, so they can sample e.g. at 200MHz, but can store only like 128k samples or less, e.g. Zeroplus LAP-(C32128).The other half are USB based, so the storage is limited only by the PC's free RAM. But they are limited by USB bandwidth which means they have relatively low sample speeds (<= 24MHz) and can reach them only for a reduced number of channels or burst signals. Typical examples are the Saleae Logic and the IkaLogic Scanalogic-2. The IkaLogic ScanaPlus is a bit more advanced as it has an FPGA to compress the data stream before sending it via USB. So it can always sample at 100MHz. Yet for continuous (clock ) signals, the USB bandwidth is usually exceeded at >=10MHz.The new Saleae line will include devices with USB3 but even they are limited to 16ch and are limited to 125MS/s in the 16ch configuration.Most people use logic analyzers as protocol analyzers for SPI/I2C/CAN etc. and for this use case, something like Saleae, ScanaPlus or even a cheap Open Logic Sniffer (45€) are much more convenient to use than a standalone LA. Then again, if you need >=32 channels at >200MHz with >1M samples, none of them will work for you.There are a few "industrial class" PC based logic analyzers. but they are much more expensive. E.g. the Zeroplus - LAP-B702000X which has 64 channels, hardware protocol triggers and 2MBit RAM per channel, but it costs > 2k€.

author: Tabs
author_rank: Regular Contributor
timestamp: May 07, 2014, 03:00:53 am
content: Check out the TravelLogic series from AcuteThese are TL2118E (18 Chan, 4GHz 18MBit) ~ $450 [probably in the region of the new SaleaesTL2136 same but with 36 chan ~$700TL2236B same but 36 chan + 72MBit ~1300I was going to purchase from Batronix who offered a 200 EUR discount because I was about to order lots of equipment.In the end, I decided to go with another supplier who beat batronix on price (for the other equipment) but couldnt offer the LA.If you have the budget to consider the new Saleae or the HPs and are looking for a PC based LA then the Acutes seem good.Haven't got one myself so make your own mind up.