Recommendations for long (5-15 meter) test leads for DMM and/or Oscilloscope?

[victorhooi]

Hi,

I need to diagnose some potential issues in the field with very long digital addressable LED strips (~ 20m long strips). The strips are glued inside an aluminum profile, which is then glued to the ceiling quite high up (there is a lift platform available). I suspect I'm going to need two people, one for each of the two probes, to push it down to the contact pads on the strips:



Thanks to @artag for some super helpful advice here.

However, even with a DMM and oscilloscope (will need to figure out a way to make my Analog Discovery ADP2230 portable, haha), I still need to find a long enough lead to reach test points along the LED strip.

My standard DMM leads are only around 36" (91cm) - and my oscilloscope leads I believe are similar.

I looked at Probemaster (where I got my leads originally), and the longest lead them have is 120" (~3m).

https://probemaster.com/9151-probe-lead/

I did find these leads online (LANG1130) - they're 30" (10m) - but they seem to have alligator clips on the end, not banana plugs - so assuming they can't be used here?

https://www.henchman.com.au/LANG1130/Test-Lead-retractable-30ft/pd.php?srsltid=AfmBOoqSVS7LykHK8ArNgl--hzX3YoB9cfHBGro9QLMYuu1hkjsv3P3k

Or there's this version - which has 3 leads - but is only 10" (3m) - and once again only has alligator clips, not banana plugs:

https://sydneytools.com.au/product/te-tools-3346-10ft-3050mm-3-colour-retractable-test-leads

Element14 also has their in-house Multicomp Pro brand ones - 5m (green), 10m (yellow), 20m (red) - however one end seems to be a fixed alligator clip as well:

https://au.element14.com/multicomp-pro/mp770519/test-lead-set-plug-alligator-clip/dp/349049202 (datasheet)

I did find RS Components does have a Test Lead Extension Reels category. In there, they have one of their in-house brand black leads, 12m long - with banana plugs on both ends :

https://au.rs-online.com/web/p/test-lead-extension-reels/6120829 (datasheet)

Mueller Electric is a US company that specializes in cables - they have these two test lead reels that are 40' (12.19m) - seem like good quality options:

https://www.muellerelectric.com/products/ai-5920t1202
https://www.muellerelectric.com/products/ai-5920t11-0

Digikey has this Pomona set - 144" (~ 3.5m):

https://www.digikey.com.au/en/products/detail/pomona-electronics/EM5908A-144/6125877

Anyway - it seems so far that the Mueller Electric set is the best option - 12m long, seem like a reputable company.

If I want 3m long ones - I guess maybe Probemaster or Pomona are the best options?

For the oscilloscope - from what I've read, I can't simply extend the existing oscilloscope probes with a BNC extension cable, right? I don't need a massive amount of bandwidth, I just want to make sure that the digital signaling for the strips is getting through (artag suggested even 10Mhz would be fine).

RS Components also has this 7.6m BNC cable:

https://au.rs-online.com/web/p/test-leads/1799397

Or what else would people suggest to extend the oscilloscope probes?

Thanks,
Victor

[KungFuJosh]

Have you considered getting a portable scope like a Micsig?

[victorhooi]

Have you considered getting a portable scope like a Micsig?

Aha - I actually have an older Micsig =) - but the battery had issues, and I found the OS a bit dinky. If you have one - how are the newer models?

However, I've just checked - the ADP2230 can apparently be powered by just USB 3.0 power alone. So if I just have my laptop, and connect that to the ADP2230, it should be portable (just not all integrated like say a Micsig, which is basically an Android tablet). From the ADP2230 spec sheet, it seems like there's some restrictions on using the ADP as power-supply when using it with just USB power - but I just need it as an oscilloscope here.

https://digilent.com/reference/test-and-measurement/analog-discovery-pro-2230/specifications

However, that still doesn't sort out the issue with the length of the DMM leads, or the oscilloscope leads - as in, if I need to read two different points that are far apart along the 20 meter LED strip.

[KungFuJosh]

I don't have a Micsig, but I know a lit of people like them for this sort of thing. My only portable scope is a toy not worthy of discussion. 😉

I guess I don't understand how you're probing. I assumed you would be going with a ground connection and probe tip to what you're testing. Ground is common throughout that strip, so I assumed you wouldn't need the leads to be long if the scope could get close.

[victorhooi]

Yes, you're right =) if I'm only measuring the data signal at one point, then I can just use a probe with a short lead, and also tap into the ground right next to it.

However, the ADP2230 I have does have two channels - so if I wanted to compare the LED data signal at the start of the strip, versus the signal later down the strip, or even towards the end - then that's where I'd need at least one of the leads to be slightly longer.

For the DMM on the other hand - I think I will probably need longer leads from the start - as I need to measure resistance between various points along the 20 metre LED strip, to see if there's any breaks in continuity (although I'm open to ideas here).

[coromonadalix]

yes  get a protable scope  ...

long wires will complicate things, antenna effects, capacitances , impedances, parasistic problems ...   and finally  safety issues

[KungFuJosh]

yes  get a protable scope  ...

long wires will complicate things, antenna effects, capacitances , impedances, parasistic problems ...   and finally  safety issues

Exactly this.

You can use 1 channel at a time on a portable scope, save screenshots with measurement data, and compare after. Live comparisons aren't necessary, and will complicate things logistically.

[victorhooi]

Hi,

Got it - yeah, I can just use a single channel on the scope, and move along the strip, bit by bit.

For the DMM - if I need to check continuity, or try to see if there are shorts between adjacent pins (e.g. data to ground).

Should I just get the 12 meter banana extensions?

https://www.muellerelectric.com/products/ai-5920t1202

Or if there another way you achieve this?

Thanks,
Victor