Prev: Mobile fMRI scanners to detect terrorists ?
Next: Shaped Noise Source (Simulation)
From: Mark Zenier on 3 Mar 2010 18:45
In article <MvqdnTwRdJpG3ejWnZ2dnUVZ_oGdnZ2d(a)earthlink.com>,
RogerN <regor(a)midwest.net> wrote:
>
>Thanks for the info. Myself not knowing anything about logic analyzers I'm
>not sure if I should get the one in your link or something like a HP 1630
>for around $100 shipped. Much of what I'm interested in would be the serial
>protocols but more like Allen Bradley Remote I/O and DH+. I have some Allen
>Bradley PLC's here at home and could set up limited communication, and try
>to determine the commands. I think the Data Highway + and Remote I/O are
>electrically RS-485, there are 2 wires and a shield for connections. They
>only range from 57.6K baud to 230.4K baud, shouldn't require anything too
>high performance.
>
>Do any of the out dated logic analyzers, such as the HP 1630(A)(D)or(G),
>1631 or 16500 show the data being communicated through serial, or is that
>more of a recent feature?

Warning, I hear the connector from the pod to the rest of the world
is unobtainium. In many cases, the pods ran plugged directly into the
microprocessor interface adaptor box and the little brown plastic
block with the patchwires, and the micrograbber clips, walked away
or got stepped on years before they got surplused. Or worse, some
gorilla was charged with collecting up anything that looked like a
cable and sending it off for copper recycling. Pod and all.

(Yow, it's been 25 years). As I remember, the 1630(D) didn't do
serial protocol analysis as a stock feature. You could customize
the unit with disassemblers and the like if you had the microcassette
drive with the A or D. (The G uses the HPIB diskette drive. I think you
could upgrade, but the G came out long after we got the D at where
I worked.)

Their speciality was state analysis (memory bus cycles) for
microcontrollers. Software machines. The A had less channels (32?)
and would max out on an 8 bit micro, the D was good for the 16+ bit
machines of the day (48? channels). One neat feature was to display
a bit field as analog oscilloscope type display (with the quirk that it
used unsigned integers so the negative numbers were on the top half,
upside down).

Timing analysis was limited to, I think, only 8 channels. And maybe
only 4 channels at top speed (100 MHz?). Not very deep, 2k samples or
something like that.

If you had to use one with a serial protocol, it might be better to
build a UART/USRT on a project board and try to figure out what you
got as parallel data.

I think that Tek or Sony/Tek was bigger with serial protocol analysers.

Mark Zenier mzenier(a)eskimo.com
Googleproofaddress(account:mzenier provider:eskimo domain:com)

From: John Larkin on 4 Mar 2010 13:12
On Thu, 11 Feb 2010 05:29:50 -0600, "RogerN" <regor(a)midwest.net>
wrote:

>
>I've been looking on eBay at logic analyzers, found some with pods and
>connectors, any recommendations?


I've never used a logic analyzer. It seems to me that there's a lot of
setup, and what it usually does is just force you to review a hardware
or software design that should have been checked more carefully at the
design stage, before it was fired up.

Just yesterday I did check the data stream from a 16M serial flash
chip that's configuring a Xilinx Spartan6 FPGA, to see if I'd got the
bit order right and such. It was easy to read on a digital scope.


>
>There are HP 1630A, 1630D, 1630G, 16500 and Tektronics 1225, 1240, 1241.
>Seems the most that have the pods are the HP with the velcro case on top.
>
>Or there are some USB logic analyzers that are in price range I'm looking at
>too.
>
>Probably my most advanced use might be to try to figure out Allen Bradley's
>RIO and DH+ communication so I could program a microcontroller to operate
>PLC5 I/O or some kind of HMI interface. Note this is for hobby use, if I
>have some sucessful designs they could be profitable but I'm not counting on
>it.

A LA could be useful there, reverse engineering a complex and
undocumented serial protocol.


>
>Any recommendations on the logic analyzers I listed above? Or others to
>search for?

My guys, who like this sort of thing, tend towards small USB pod
things.


John

From: krw on 4 Mar 2010 18:28
On Thu, 04 Mar 2010 10:12:38 -0800, John Larkin
<jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote:

>On Thu, 11 Feb 2010 05:29:50 -0600, "RogerN" <regor(a)midwest.net>
>wrote:
>
>>
>>I've been looking on eBay at logic analyzers, found some with pods and
>>connectors, any recommendations?
>
>
>I've never used a logic analyzer. It seems to me that there's a lot of
>setup, and what it usually does is just force you to review a hardware
>or software design that should have been checked more carefully at the
>design stage, before it was fired up.

There universe of errors is far larger than design.

>Just yesterday I did check the data stream from a 16M serial flash
>chip that's configuring a Xilinx Spartan6 FPGA, to see if I'd got the
>bit order right and such. It was easy to read on a digital scope.

For simple problems like that I use a scope too. Many problems are a lot
deeper and some only happen once a blue moon. Logic analyzers are invaluable
for tracking these down. As you point out, they're a lot of work to get set
up so I rarely use them but when they're called for they can be life savers.

>>
>>There are HP 1630A, 1630D, 1630G, 16500 and Tektronics 1225, 1240, 1241.
>>Seems the most that have the pods are the HP with the velcro case on top.
>>
>>Or there are some USB logic analyzers that are in price range I'm looking at
>>too.
>>
>>Probably my most advanced use might be to try to figure out Allen Bradley's
>>RIO and DH+ communication so I could program a microcontroller to operate
>>PLC5 I/O or some kind of HMI interface. Note this is for hobby use, if I
>>have some sucessful designs they could be profitable but I'm not counting on
>>it.
>
>A LA could be useful there, reverse engineering a complex and
>undocumented serial protocol.

Or violations of protocol (parallel or serial).

>>
>>Any recommendations on the logic analyzers I listed above? Or others to
>>search for?
>
>My guys, who like this sort of thing, tend towards small USB pod
>things.

Never used one of those, but perhaps it's time. ;-)
First  |  Prev  | 
Pages: 1 2 3 4 5 6
Prev: Mobile fMRI scanners to detect terrorists ?
Next: Shaped Noise Source (Simulation)