Oscilloscopes

miso_at_sushi.com wrote:
On Feb 7, 1:57 pm, D Yuniskis <not.going.to...@seen.com> wrote:
RogerN wrote:
What's the best scope to get for the money for mostly digital circuits?
I'll have some analog but nothing real high frequency, like analog
But, your *digital* stuff *will* be "high frequency" (at least
considerably higher than the analog examples you mentioned)

connections to the microcontroller, maybe some SMPS circuits. I was looking
at some microcontroller and fpga designs that you can get kits starting at
less than $100 and going up with more speed and features. Also, I see on
eBay you can get some nice looking Techtronics scopes for $350 or so, 4
channel digital, etc. Just wondering if something like the AVR scope would
be a useful tool or if I would be wishing I went ahead and bought a nice
used scope on eBay.
You might look into an older logic analyzer "for mostly digital
circuits". Often, the cost of shipping is the biggest expense! :

Of course, it also depends on the types of problems you are
trying to troubleshoot with the device...

If you get a used logic analyzer, make sure it has the "pods". I'm
simply amazed at how the box and pods get separated.

Ah, yes. And, more importantly, any *micrograbbers* that
might be attached to the pods! Otherwise, you'll spend more
on *those* than the logic analyzer itself! :

Drag it out and use it. You'll quickly learn what features you need.

Do you have any recommendations on a
used repairable scope?
Already done that TEK 465, 7704 and relatives.
The 7704 is handy 'cause you can get plugins for logic analysis,
spectrum analysis, TDR, curve tracer etc.
I've seen some recommend the Techtronics 465, since
a lot of what I plan to use it on is digital signals/communication, I
thought storage would almost be necessary.

You need to say a LOT more about what you mean by digital
signals/communication.
RS-232 is communication and well within the capability of your leader.
Demodulating Cellphone signals is quite another matter.

An oscilloscope is a poor substitute for good design judgment.

Once you get beyond that, it becomes complicated real fast.
Just probing the system is a nightmare.
Your problem is triggering on the desired event. You quickly get into
logic analyzer types of triggering and display. A two-channel scope
is better than one. 4 is better, but still not too helpful if you
need to trigger on 8 or 64. I once got so frustrated that I built a fixture
with a PAL on it. Reprogrammed the PAL for each complex trigger
and used that as one channel into a logic analyzer.

Digital storage has some benefits.
Lets you see what happened to signals WAY before the trigger event.
But you still have to come up with some way to trigger on the symptom.

You can do a lot of stuff with a cheap analog scope.
Complex stuff needs $60K equipment.
There ain't much in between. Might as well go cheap
and suffer the consequences of not being able to do some stuff.
Patience pays off when you're looking for equipment.

On Feb 7, 1:57 pm, D Yuniskis <not.going.to...@seen.com> wrote:
RogerN wrote:
What's the best scope to get for the money for mostly digital circuits?
I'll have some analog but nothing real high frequency, like analog

But, your *digital* stuff *will* be "high frequency" (at least
considerably higher than the analog examples you mentioned)

connections to the microcontroller, maybe some SMPS circuits.  I was looking
at some microcontroller and fpga designs that you can get kits starting at
less than $100 and going up with more speed and features.  Also, I see on
eBay you can get some nice looking Techtronics scopes for $350 or so, 4
channel digital, etc.  Just wondering if something like the AVR scope would
be a useful tool or if I would be wishing I went ahead and bought a nice
used scope on eBay.

You might look into an older logic analyzer "for mostly digital
circuits".  Often, the cost of shipping is the biggest expense!  :

Of course, it also depends on the types of problems you are
trying to troubleshoot with the device...

If you get a used logic analyzer, make sure it has the "pods". I'm
simply amazed at how the box and pods get separated.

D Yuniskis <not.going.to.be_at_seen.com> wrote:

miso_at_sushi.com wrote:
On Feb 7, 1:57 pm, D Yuniskis <not.going.to...@seen.com> wrote:
RogerN wrote:
What's the best scope to get for the money for mostly digital circuits?
I'll have some analog but nothing real high frequency, like analog
But, your *digital* stuff *will* be "high frequency" (at least
considerably higher than the analog examples you mentioned)

connections to the microcontroller, maybe some SMPS circuits. I was looking
at some microcontroller and fpga designs that you can get kits starting at
less than $100 and going up with more speed and features. Also, I see on
eBay you can get some nice looking Techtronics scopes for $350 or so, 4
channel digital, etc. Just wondering if something like the AVR scope would
be a useful tool or if I would be wishing I went ahead and bought a nice
used scope on eBay.
You might look into an older logic analyzer "for mostly digital
circuits". Often, the cost of shipping is the biggest expense! :

Of course, it also depends on the types of problems you are
trying to troubleshoot with the device...

If you get a used logic analyzer, make sure it has the "pods". I'm
simply amazed at how the box and pods get separated.

Ah, yes. And, more importantly, any *micrograbbers* that
might be attached to the pods! Otherwise, you'll spend more
on *those* than the logic analyzer itself! :

The rate at which micrograbbers release themselves is
e^number_of_grabbers per hour. Besides with current devices you're
better of soldering thin wires directly to a header which connects to
the pod.

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

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.

On Sun, 7 Feb 2010 23:24:33 -0800 (PST), "miso_at_sushi.com" =
miso_at_sushi.com> wrote:

On Feb 7, 1:57=A0pm, D Yuniskis <not.going.to...@seen.com> wrote:
RogerN wrote:
What's the best scope to get for the money for mostly digital =
circuits?
I'll have some analog but nothing real high frequency, like analog

But, your *digital* stuff *will* be "high frequency" (at least
considerably higher than the analog examples you mentioned)

connections to the microcontroller, maybe some SMPS circuits. =A0I =
was looking
at some microcontroller and fpga designs that you can get kits =
starting at
less than $100 and going up with more speed and features. =A0Also, I=
see on
eBay you can get some nice looking Techtronics scopes for $350 or =
so, 4
channel digital, etc. =A0Just wondering if something like the AVR =
scope would
be a useful tool or if I would be wishing I went ahead and bought a =
nice
used scope on eBay.

You might look into an older logic analyzer "for mostly digital
circuits". =A0Often, the cost of shipping is the biggest expense! =
=A0:

Of course, it also depends on the types of problems you are
trying to troubleshoot with the device...

If you get a used logic analyzer, make sure it has the "pods". I'm
simply amazed at how the box and pods get separated.

I am not sure that i would even bother with used logic analyzers,=20
USB pods are cheaper and usually fast enough (100 Mstates/s with=20
glitch capture). If your speeds are greater than that you need to=20
consider alternative data capture methods.

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

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.

"JosephKK"<quiettechblue_at_yahoo.com> wrote:

On Sun, 7 Feb 2010 23:24:33 -0800 (PST), "miso_at_sushi.com" >><miso_at_sushi.com> wrote:

On Feb 7, 1:57=A0pm, D Yuniskis <not.going.to...@seen.com> wrote:
RogerN wrote:
What's the best scope to get for the money for mostly digital >>circuits?
I'll have some analog but nothing real high frequency, like analog

But, your *digital* stuff *will* be "high frequency" (at least
considerably higher than the analog examples you mentioned)

connections to the microcontroller, maybe some SMPS circuits. =A0I >>was looking
at some microcontroller and fpga designs that you can get kits >>starting at
less than $100 and going up with more speed and features. =A0Also, I>> see on
eBay you can get some nice looking Techtronics scopes for $350 or >>so, 4
channel digital, etc. =A0Just wondering if something like the AVR >>scope would
be a useful tool or if I would be wishing I went ahead and bought a >>nice
used scope on eBay.

You might look into an older logic analyzer "for mostly digital
circuits". =A0Often, the cost of shipping is the biggest expense! >>=A0:

Of course, it also depends on the types of problems you are
trying to troubleshoot with the device...

If you get a used logic analyzer, make sure it has the "pods". I'm
simply amazed at how the box and pods get separated.

I am not sure that i would even bother with used logic analyzers,=20
USB pods are cheaper and usually fast enough (100 Mstates/s with=20
glitch capture). If your speeds are greater than that you need to=20
consider alternative data capture methods.

I recently purchased a used logic analyzer from Tek for $450. I looked
at the USB LAs as well but if you want something nice (lot of depth,
at least 1Gs/s, versatile triggering and input specifications
specified at the tip of the probe) you'll pay a lot more.

On Sun, 7 Feb 2010 15:31:46 -0600, "RogerN" <regor_at_midwest.net> wrote:


What's the best scope to get for the money for mostly digital circuits?
I'll have some analog but nothing real high frequency, like analog
connections to the microcontroller, maybe some SMPS circuits. I was looking
at some microcontroller and fpga designs that you can get kits starting at
less than $100 and going up with more speed and features. Also, I see on
eBay you can get some nice looking Techtronics scopes for $350 or so, 4
channel digital, etc. Just wondering if something like the AVR scope would
be a useful tool or if I would be wishing I went ahead and bought a nice
used scope on eBay.

"The" AVR scope? Hard to comment on it, knowing only that...

In general, though, USB-based scopes typically don't have particularly
high sample rates. I'd suggest looking into one of the smaller "real"
digital 'scopes, such as Instek or Rigol. There was a loooong discussion
on this back in December in this group with the subject "A good digital
oscilloscope?" (As you may imagine, this comes up fairly often here.)

A USB logic analyzer, on the other hand, is a useful gadget. I've been
using an Intronix for years and wouldn't go anywhere without it. Overdue
for a new model, though. http://www.pctestinstruments.com/

On Thu, 11 Feb 2010 05:29:50 -0600, "RogerN" <regor_at_midwest.net> wrote:


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

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.

As mentioned up above, I use http://www.pctestinstruments.com/. Your
mileage may vary.

Some things to consider:

1. The USB logic analyzers tend to split into two groups based on their
capture mode. There is a group with deep sample memory that always
captures in real time. This leads to a trade-off between duration and
precision, where sampling at 100 MHz into a 1 Mb buffer fills the buffer
in only 10 msec.

The other class has shallower buffers (typically a few Kb) but can tag
each sample with a timestamp, so sampling at 100 MHz is still possible
throughout an event that lasts several seconds. On the other hand, if
there's a channel with a lot of activity then the buffer will be filled
correspondingly quickly.

2. Pay attention to the maximum input voltage range and also to the
trigger range. There are some inexpensive USB LAs that have a fixed
front-end range of 0-5 VDC and a fixed trigger threshold but ones that
handle at least +/- 20 VDC with adjustable triggers aren't much more
expensive.

3. Back in the day, one feature of LAs was the ability to load a machine
language interpreter and, with the proper assignment of channels to
address, data, and control busses, to trace program execution and
trigger on events like the change of a memory location. Nowadays, at
least in microcontroller land, not so much. Instead, look for the
ability to interpret common serial protocols like CANbus, I2C, etc.

--
Rich Webb Norfolk, VA

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?

On Thu, 11 Feb 2010 18:01:22 GMT, nico_at_puntnl.niks (Nico Coesel) wrote:

"JosephKK"<quiettechblue_at_yahoo.com> wrote:

On Sun, 7 Feb 2010 23:24:33 -0800 (PST), "miso_at_sushi.com" =3D
miso_at_sushi.com> wrote:

On Feb 7, 1:57=3DA0pm, D Yuniskis <not.going.to...@seen.com> wrote:
RogerN wrote:
What's the best scope to get for the money for mostly digital =3D
circuits?
I'll have some analog but nothing real high frequency, like analog

But, your *digital* stuff *will* be "high frequency" (at least
considerably higher than the analog examples you mentioned)

connections to the microcontroller, maybe some SMPS circuits. =
=3DA0I =3D
was looking
at some microcontroller and fpga designs that you can get kits =3D
starting at
less than $100 and going up with more speed and features. =
=3DA0Also, I=3D
see on
eBay you can get some nice looking Techtronics scopes for $350 or =
=3D
so, 4
channel digital, etc. =3DA0Just wondering if something like the =
AVR =3D
scope would
be a useful tool or if I would be wishing I went ahead and bought =
a =3D
nice
used scope on eBay.

You might look into an older logic analyzer "for mostly digital
circuits". =3DA0Often, the cost of shipping is the biggest expense! =
=3D
=3DA0:

Of course, it also depends on the types of problems you are
trying to troubleshoot with the device...

If you get a used logic analyzer, make sure it has the "pods". I'm
simply amazed at how the box and pods get separated.

I am not sure that i would even bother with used logic analyzers,=3D20
USB pods are cheaper and usually fast enough (100 Mstates/s with=3D20
glitch capture). If your speeds are greater than that you need to=3D20
consider alternative data capture methods.

I recently purchased a used logic analyzer from Tek for $450. I looked
at the USB LAs as well but if you want something nice (lot of depth,
at least 1Gs/s, versatile triggering and input specifications
specified at the tip of the probe) you'll pay a lot more.

At that speed the choices are get good stuff or go without. Did that =
price=20
include pods and probes?

On Sun, 07 Feb 2010 17:29:36 -0500, Rich Webb <bbew.ar_at_mapson.nozirev.ten> wrote:

On Sun, 7 Feb 2010 15:31:46 -0600, "RogerN" <regor_at_midwest.net> wrote:


What's the best scope to get for the money for mostly digital circuits?
I'll have some analog but nothing real high frequency, like analog
connections to the microcontroller, maybe some SMPS circuits. I was looking
at some microcontroller and fpga designs that you can get kits starting at
less than $100 and going up with more speed and features. Also, I see on
eBay you can get some nice looking Techtronics scopes for $350 or so, 4
channel digital, etc. Just wondering if something like the AVR scope would
be a useful tool or if I would be wishing I went ahead and bought a nice
used scope on eBay.

"The" AVR scope? Hard to comment on it, knowing only that...

In general, though, USB-based scopes typically don't have particularly
high sample rates. I'd suggest looking into one of the smaller "real"
digital 'scopes, such as Instek or Rigol. There was a loooong discussion
on this back in December in this group with the subject "A good digital
oscilloscope?" (As you may imagine, this comes up fairly often here.)

A USB logic analyzer, on the other hand, is a useful gadget. I've been
using an Intronix for years and wouldn't go anywhere without it. Overdue
for a new model, though. http://www.pctestinstruments.com/

That is pretty good for an LA at that price.

"Rich Webb" <bbew.ar_at_mapson.nozirev.ten> wrote in message
news:8108n556skp2jcrdblfpl3eh4i8cuumil1_at_4ax.com...
On Thu, 11 Feb 2010 05:29:50 -0600, "RogerN" <regor_at_midwest.net> wrote:


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

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.

As mentioned up above, I use http://www.pctestinstruments.com/. Your
mileage may vary.

Some things to consider:

1. The USB logic analyzers tend to split into two groups based on their
capture mode. There is a group with deep sample memory that always
captures in real time. This leads to a trade-off between duration and
precision, where sampling at 100 MHz into a 1 Mb buffer fills the buffer
in only 10 msec.

The other class has shallower buffers (typically a few Kb) but can tag
each sample with a timestamp, so sampling at 100 MHz is still possible
throughout an event that lasts several seconds. On the other hand, if
there's a channel with a lot of activity then the buffer will be filled
correspondingly quickly.

2. Pay attention to the maximum input voltage range and also to the
trigger range. There are some inexpensive USB LAs that have a fixed
front-end range of 0-5 VDC and a fixed trigger threshold but ones that
handle at least +/- 20 VDC with adjustable triggers aren't much more
expensive.

3. Back in the day, one feature of LAs was the ability to load a machine
language interpreter and, with the proper assignment of channels to
address, data, and control busses, to trace program execution and
trigger on events like the change of a memory location. Nowadays, at
least in microcontroller land, not so much. Instead, look for the
ability to interpret common serial protocols like CANbus, I2C, etc.

--
Rich Webb Norfolk, VA

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?

RogerN