Recent Posts

1

Test Equipment / Re: SDS800X HD Wanted Features

« Last post by electronics hobbyist on Today at 10:34:13 am »

Feature request 1: bit rate measurement, please!

This is good feature, will added to wanted feature No.36.

2

General Technical Chat / Re: Does the electrical grid acompany network lines?

« Last post by ELS122 on Today at 10:28:22 am »

I mean in the US and the power grid infrastructure, not local housing electric supplies. I'm trying to find whatever possible attack vectors someone could have if they were connected to the main power grid. Because of all the suspicious windmill connections in areas you wouldn't expect anyone to build windmills in... Gives you the question if they have some kind of attack vector by doing that.

  

No, it does not give me that question.

You mean "they" are building windmills because they want to eavesdrop on you? I can put your mind at ease there; no functionality for that "attack vector" is built in. But don't tell anybody: "They" have installed secret switches where they can turn all the windmills into huge fans and cause massive storms in your area!

No, one would imagine that targeting infrastructure would be to target infrastructure and take it down in case of idk... for example a war.
I'm just asking as a hypothetical because it's a pretty relevant discussion at this time of elevated world conflict. you wouldn't want to ask if it was possible "after" it's done.

The "power grid" is nothing more or less than the high voltage, medium voltage, and low voltage power lines that carry the electric power from the machinery that generates it to the point of use (homes and businesses). 60 Hz in the US and 50 Hz in many other places.

Now, the power companies do need to have communication equipment to monitor the state of that grid and to control the various elements (generators, switches, etc.) I would suspect that they use multiple means of communication: microwave, satellite, plain old radio, probably even land (telephone) lines. But, of course even the telephone lines use things like microwave and satellite for long, cross country connections.

But, another thing that I am fairly sure is done is to transmit digital data using those very power transmission lines that form the power grid, or at least parts of it. When I drive under the some local semi-HV power lines my AM radio picks up a lot of static that sounds a lot like digital chatter to me. So the logical conclusion is that those power lines are also carrying digital communication signals that are piggy-backed on the 60 Hz, AC power. This superimposed data signal is probably carrying the monitoring and control signals that the power company uses, as I mentioned above.

Thus, I think that there is no simple answer to the OP's question.

As far as attack vectors, that would be tricky. I mean, these digital signals would not pass through AC transformers very easily. They would need to be stripped of the 60/50 Hz power on one side of the transformer and re-inserted on the other. If the power company had not provided that path, then the first transformer that any malicious hacker's connection encountered would be a dead end. So one could not just connect to a household or business power connection (230 VAC) and expect to receive, alter, and re-transmit those monitoring or control signals.

A hacker would be far more likely to interfere with the control of the power grid by hacking into any internet connections that the power companies are using. One can only hope their engineers are wise enough to guard against any such intrusion. And do consider the fact that the power lines that carry that power for any appreciable distance (like over a kilometer) are virtually all high voltage lines. A hacker attempting to make a connection to them would need a fair amount of equipment to do so. Things like an insulated bucket truck and the equipment that makes the connection would need to be designed for those high voltages. And, of course, the training to properly use them.

Of course anything is possible where technology is involved. Just ask the Germans or Japanese officials who thought their WWII codes were completely secure. I am sure there are malevolent people who are trying to find the weak points in these systems for possible use when they wish.

So you're saying that power companies modulate power lines carrying millions of watts of power with high frequency digital data? I dont see how that can ever be practical in any world...
How would the power infrastructure ensure that for example; a hard short in the windmill; an intentional hard short on the connection to the grid; some other malfunction doesnt down the grid? there obviously is some type of system that ensures these things down happen. Which is what I'm asking about... how that works.

3

Repair / Re: fluke 112 eeprom error

« Last post by Shock on Today at 10:25:05 am »

My understanding is that Fluke service mostly part swap (unless it's a clean or calibration). This model can go cheap online as they aren't so common or obvious that it's a nice model. Might have to wait a bit for firmware, in the meantime you could provide details on the part you're programming and board revision.

Some other details like how it got that error is also useful. As meters get contaminated by old batteries I'd have checked that first. If you break a leg often you can carefully excavate the package to expose enough to connect a wire on. See if it's essential for programming in the datasheet. You may have to wire it to a sacrificial socket/pcb in order to read/program easily or reliably.

4

Test Equipment / Re: Magnova oscilloscope

« Last post by mubes on Today at 10:24:19 am »

My word, in the absence of much useful signal yet the AGC certainly has amplified a lot of noise in here.

Batronix should be judged by their actions, not whatever prejudices any of us choose to hold. Let's wait and see what they tip up with.  Personally I'm excited to see a new entrant into the market trying to stir things up...with the background and experience across a whole range of existing products to know what works and what doesn't. Given where they're positioning this there's a decent chance they might actually listen to people and add in features that the big players simply don't have....I already messaged them privately about one such feature I'd love to see - I'd even help them implement it!

It could be crock, it could be fantastic. Based on my interactions with the company in the past I've hopeful it's the latter, but none of us can know until the dammed thing turns up.

5

Test Equipment / Re: SDS800X HD Wanted Features

« Last post by hansibull on Today at 10:23:14 am »

Good suggestion for the entire platform range and one I believe could be accomplished quite simply by adding a menu View (type) option in the Decode List comprising of a Bytes or Frames choice, Bytes being the current list default view.

Ideally, they should also add a "packet timeout" value so that closely spaced packets/bursts of data can easily be separated. but the RTB2004 doesn't have such functionality, and I've never had any issues with UART "packets" being interpreted as one single packet.

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Test Equipment / Re: SDS800X HD Wanted Features

« Last post by 2N3055 on Today at 10:20:37 am »

Just unboxed my new scope and getting to grips with it - apologies if this is just a setting which can be changed somewhere, but it seems unintuitive and a limitation...

I'm probing a CAN signal - actually one of the training outputs from my MSOX3104A - and before I can decode it, I need to know the bit rate.

I couldn't find an automated measurement that gives this quickly and easily. IIRC it was added in firmware after release on the Agilent, and it's handy. I think it just measures the minimum observed pulse width (either positive or negative) within the captured data.

Feature request 1: bit rate measurement, please!

In the absence of an automatic measurement, I figured I'd just do it the old-fashioned way. Capture a packet, find the narrowest pulse and assume it's 1 bit wide. Then, put the cursors on the edges as accurately as possible, and measure their separation.

The odd behaviour is that the delta-X measurement on screen doesn't show the distance between the cursors if one of them is off screen; instead, it 'clips' to the edge of the screen, and if both are off screen then it just reports the width of the screen, or zero if both cursors are off to the same side.

That's really misleading. It clearly remembers the correct cursor positions if they're pushed off screen, because they come back to the right place if I adjust the time base to bring them back.

If I were feeling unkind, I'd call this a bug, though it's clearly intentional behaviour. I just can't think of any circumstances when I'd want to measure between a cursor and the edge of the display, as opposed to between the two cursors.

Feature request 2: delta-X time measurement actually measures the time between X1 and X2 even if one or both of them is off screen - not between a visible cursor and the edge of the screen.

(Example photos: both cursors on screen, showing delta-X = 8.01us, and the effect of just speeding up the time base 1 click; this pushes X1 off the left side of the screen, and the delta-X readout becomes 6.77us which is effectively meaningless).

I asked about Bit rate measurement long time ago... Will repeat...
In meantime depending on signal being idle high or low, i enable +Pulse Width or +Pulse Width and stats and look for minimum value. 1/t gives frequency i.e baud rate.
But yeah I miss that too, coming from Keysight. Not really needed (you can do what I explained, or just use cursors on visually shortest pulse) but a giant time saver.
Especially if you are doing µC work and doing custom baud rates etc...

As for cursor behaviour it is not a bug.
Scope's capture ENDS with the end of screen.
So it will remember what you set for cursor, because you can magnify the portion of screen to set cursor more accurately, magnify other event set that one, and then st time base to have both cursors on the screen to measure.

7

Power/Renewable Energy/EV's / Re: How to test an IR2104/2111?

« Last post by DELTA67 on Today at 10:15:25 am »

I thought that photo was from your real scope? 

Sorry if I've not been clear on that point.
The scope picture is from the simulation on PROTEUS.
If it was from the real device then there's no need to open this thread!!!

Now I've changed the power Vcc to 14V, the chip get's very hot.
Can the uC drive directly the chip or I must use a buffer?
are these chips(IR2104/2111) cloned?

8

Test Equipment / Re: Hacking the Rigol MSO5000 series oscilloscopes

« Last post by BTO on Today at 10:14:01 am »

Try to uninstall all options first, wait for reboot, then install with regen private key flag.

I tried as described, first uninstalled and after reboot I installed with regen private key. Tried it several times but the oscilloscope only replies with "remaining attempts" as described by zauberpilz, now only 2 attempts left. What am I doing wrong? Could you please help?

Hey mate, Just wondering, How are you going with unlocking the scope.
Have you tried the method that i stated ?
You can keep persisting the method that you're doing or
You can do the method that i've put forward that we know works.

Just making sure everyone is up to date

9

Beginners / Re: good/cheap headphone aplifier/dac?

« Last post by BeBuLamar on Today at 10:08:19 am »

If you like the Bose QC25 why not just buy another?

10

Repair / Re: Artesyn LPT42 SMPS repair

« Last post by zkrx on Today at 10:06:33 am »

Thank you so much. I still have a few incandescent bulbs lying around.

Any tip for testing IC1 (3842) or should I just blindly swap & test?