Lost contact with ROV

Blue Robotics Vehicles BlueROV2 Heavy
1

Hi

I have an BlueROV2 Heavy with Raspberry Pi 4 and Navigator ++, from 2019-2024

I have not used the ROV for about 11 months.

A couple a days ago I upgrade the BlueOS to Stable v1.4.2…

Everything was ok and I setup the vehicle….

After a while I lost communication with the ROV.

Power and Link LED on Fathom-X Tether interface (FXTI) is ON when I connect the USB cable to Computer.

I have checked that the tether is OK.

No lights on ethernet port of Rasphberry Pi 4.

If I use a ethernet cable direct from computer to Rasphberry Pi 4 the lights on ethernet port of Rasphberry Pi 4 i lights yellow, but still NO contact with ROV.

I get contact with ROV (BlueOS) thru wi-fi.

I think I have allowed the software to communicate thrue Firewall.

Here is my Ipconfig and ping results with use of Fathom-X Tether interface (FXTI)

{EEBA5712-EBF6-4D19-8EFA-270026B2483F}
{EEBA5712-EBF6-4D19-8EFA-270026B2483F}1346×1353 37.4 KB

What to do, what is wrong ??

Best regards

Erland Hansen

2

Hi @erhan -

Sorry for the issue! If you don’t see ethernet lights with the Fathom-X connected to the pi, you could have an issue with that short ethernet cable, or the Fathom-X in the ROV itself - despite the green link light. When you connect directly, it is strange that you still can’t reach the interface! Is the Blue light flashing on the Navigator, indicating that the system started up ok? Do you hear a beep from the thrusters a minute or two after connecting power, indicating the same?

Have you switched computers, had a leak, or changed your hardware or software in any other way?

If you’re able to reach the BlueOS interface via WiFi, you could use the tether diagnostic extension to understand what’s happening with the connection - please share screenshots of that interface once you’ve installed it!

3

Hi Tony

Thanks a lot for reply :slightly_smiling_face:

I found the fault, I think the cable for the Power to the onboard Ethernet Switch is broken.

I connect the Ethernet cable directly from Fathom-X Tether interface to the Raspberry Pi 4.

(Bypassing the Ethernet Switch onboard ROV)

Tomorrow I will fix a new cable to Power the Ethernet Switch.

By the way…I replaced the Raspberry Pi 4 8GB with an Raspberry Pi 4 2GB, to test if a bad Raspberry Pi 4 was the reason….

Which of these do you recommend ?

Best Regards

Erland

4

Hi @erhan -

Glad you found the problem!

The amount of RAM shouldn’t make too much of a difference to BlueOS, but if you’re using a lot of extensions and other software add-ons, the more the better!

5

Hi again Tony.

Thanks for advice about Raspberry Pi, I have installed the 8GB unit back in the ROV.

“Unfortunately” the power cable to Ethernet Switch was ok.

So the Ethernet Switch have to be replaced.

Thanks anywhy for the help.

Best Regards

Erland

6

Hi @erhan -

Can you describe the behavior of the lights on the bad Ethernet Switch? It may be affected by a known issue, please report the issue via the help center, report a problem with a product. It may be possible to fix, or you may be due a replacement.

7

Hi Tony

No lights at all on the Ethernet Switch with all Ethernet cables connected.

The Blue light flashing on the Navigator, and I hear a beep from the thrusters a minute after connecting power.

I do a Tether Diagnostics thru Wi-fi in the BlueOS and no traffic at all in both curves.

(Yesterday, I do the same Tether Diagnostics without the Ethernet Switch, and there was a lot of traffic and 150Mbps.)

Earlier today, I report the problem with the product via the help center, awaiting answer.

Erland

8

Hi Tony

I bought a new Ethernet Switch (with a -$35 refund from sales) and replaced the bad one.

Power and port LED’s are one when in use.

But still the same communication problem.

I bypassed the Ethernet Switch and still problem…

Here are my screenshots without Ethernet Switch……

image
image945×591 57.9 KB

I get contact thru the WIFI and here are the Tether Diagnostics

(When no webcontact at 192.168.2.2)

The Green and Yellow LED’s at the RJ45 contact at the Fathom-X onboard are blinking.

Both LED’s at the Fathom-X Tether Interface (FXTI) are on when the USB cable is connected to Computer.

image
image945×591 114 KB

See this screenshot, USB not connected, maybe at the Pi4 ?

image
image945×509 72.2 KB

Here are my ethernet settings (Win 11)

image
image945×684 82.5 KB

Here are my Firewall settings Norton 360 for Gamers, App permissions

image
image945×636 97.8 KB

And here the “Safe Web”

image
image945×591 45.7 KB

What to do ?

I have also tried 2 another Computers, no contact.

Best Regards

Erland

9

Hi @erhan
That definitely seems like a problem with your Fathom-X module or tether! I’d suspect the tether more likely… because one half of the connection seems to be there, and the other isn’t at all (Blue/Purple lines in upper right). This is a mode of connection that I don’t think we’ve seen before - very interesting! The green line graph below it also looks abnormal - typically it drops off to 0 on the y axis as Offset increases (not sure what these terms mean, it’s all a bit of black magic to me!)

Can you check the resistance of the tether pair you’re using, and swap to another one to test (making the switch in both topside FXTI box and the ROV enclosure, at the Fathom-X.) If the polarity is reversed, that isn’t a problem!

image
image1572×1252 98.3 KB

10

Hi Tony

Thanks again for reply.

I have measured all 4 pair in the Tether, here are the result:

Pair: Hvite-Blue, loop= 56.7 ohm, (hvite= 28 ohm, Blue= 28.6 ohm)

Pair: Hvite-Green, loop= 57.7 ohm, (hvite= 28.9 ohm, Green= 28.9 ohm)

Pair: Hvite-Yellow, loop= 59 ohm, (hvite= 29.4 ohm, Green= 29.4 ohm)

Pair: Hvite-Brown, loop= 55 ohm, (hvite= 29.2 ohm, Brown= 25.9 ohm)

I tested with pair Hvite-Brown, no differnce, NO connection.

Here are a new Tether Diagnostics, thru ROV’s WIFI (pair Hvite-Brown):

Same result with pair Hvite-Blue (default)

{604ED0B9-3723-4D56-A694-9E00B02193CA}
{604ED0B9-3723-4D56-A694-9E00B02193CA}2560×1600 394 KB

I guess I have to buy a new Fathom-X Tether Interface Board BR-100023, or maybe two pieces ?

Maybe better with one Fathom-X Tether Interface Board BR-100023,

and one Fathom-X Tether Topside Interface (FXTI) BR-100679 ?

Any suggestions ?

Do you know about any issues with the Fathom-X Tether Topside Interface (FXTI) ?

Best regards

Erland

11

Hi @erhan -

Do none of the pairs work? How long is your tether?

Did you change the tether pair connected in two locations?

The Fathom-X is inside the FXTI, so you only need the Fathom-X Tether interface board BR-100023… replacing both is your best bet…

I’m not aware of any issues with these modules, but they are particularly sensitive to moisture exposure and corrosion in the long term…

12

Hi Tony

None of the pairs work.

My Tether is 200m (656ft) long, with Fathom Spool - Large (300m).

I have made a custom built connections from SeaCon (Micro Wet-con)

(These tether and everrything have functioning very well since 2020)

Here is a new Tether Diagnostics, I disconnect and reconnect the Binder connector from the Fathom-X Tether Topside Interface.

{B28C738C-9663-4E01-93B2-DBA3200E0B21}
{B28C738C-9663-4E01-93B2-DBA3200E0B21}2560×1600 403 KB

See this screenshot, usb0 not connected, what that means ?

image

When I disconnect the binderplugg from Fathom-X Tether Topside Interface the LED “Link Active” is still ON, is this correct ?

Regards

Erland

13

Hi @erhan -

I would suspect your modification of the connector to use a SubCon?

USB0 is related to modems that can be connected via USB, it can be ignored.

You could try shortening the tether, and re-terminating it?

You could also try another tether or length of twisted wire between the two Fathom-X modules, to verify they connect well and are functioning as expected.

If the link light remains on when the tether is completely disconnected, something is definitely wrong with at least that Fathom-X! It should go off within a few seconds, and if it ever goes off, no link can be expected.

14

Hi Tony

The ROV is heavy (15kgs) and with a 200m tether on the Fathom Spool I had to make that modification to split the ROV and Fathom Spool, so I could handle the stuff to the sea alone.

I bougth that Seacon connectors from www.outlandtech.com to a custom ROV project…

I soldered/insulated the leaders in the tether and made the joint waterproof with 2131B 3M Scotchcast Potting Compound. Douth if there is wrong on it, but I will check it out.

(That said, worked brilliant from 2020 to 2024 with several dive)

I test with a spare cable 1-pair nonshielded, same result.

I have ordered 2 pieces of Fathom-X Tether interface board BR-100023 and

one 128 GB micro SD card preloaded with BlueOS, if something strange is happens to that card I have installed at the moment.

That ohm values I measured, are these ok ?

I hope I will solve the problem when I change the The Fathom-X’s.

Thanks

Regards

Erland

15

Hi @erhan -

In my experience, any connection that relies on potting compound will not live forever! It is impressive that yours has lasted 4 years… I’m eagerly awaiting the Blue Robotics WetLink connector launch - it uses 0 potting to seal to 1000m!

Is the spare cable you tested using a twisted pair? This is required….

If your tether is standard Blue Robotics Fathom tether, the resistance spec is 0.127 0.127 Ω/m/m, so the values you’re measuring seem close to the 25.4 Ω predicted. Beyond resistance, the impedance is what is tricky to measure and is important to the Fathom-X for connection!

I don’t think your issue is related to the SD card or BlueOS, for the record!

16

Hi Again Tony

Thanks

You have RIGHT regarding that any connection that relies on potting compound will not live forever :slight_smile:

Suddenly when I hold on with check of the tether, the blue conductor in pair white-blue was broken….

The frakture is at the end of the potting compound….I hope some other pair is ok, but may some short -circuit in the potting compound causing the damage of Ethernet Switch/Fathom-X’s ?

I don’t use a twisted cable, I will try one tomorrow.

Yes, I think my tether is standard Blue Robotics Fathom tether.

What are people doing, direct connect of tether to the ROV without any connector or ?

I can maybe order some WetLink Penetrator (7.5mm or 8.0mm) for the Fathom tether….

Erland

17

Hi @erhan -

While we wait for the Blue Robotics solution, many folks are using Blue Trails to connectorize their ROV! This still relies on potting, but not much of it, and a metal connector helps… The default is indeed to use a 7.5mm HC WetLink Penetrator!

18

Hi Tony

Thanks a lot for your help :slightly_smiling_face:

I will replace that seacon connector and use a 7.5mm HC WetLink Penetrator for the tether !

I hope that and new Fathom-X’s, will solve my problems.

Have a good evening…:sun_with_face:

Best regards

Erland

19

Hi Again Tony

The communication problem has finally been resolved :smiley:

But it is a little strange….. :roll_eyes:

I cut the cable, and reconnected the white-blue pair in the ROV.

I replaced the Fathom-X at the ROV, still no contact.

I replaced the Fathom-X at the FXTI, still no contact.

Then I replaced the micro SD card in the Pi4 with a new one preloaded with BlueOS.

Then voila, communication re-established ! Strange ?

Then I replaced both Fathom-X’s, still ok.

Then I installed the new Ethernet Switch and everything are functioning.

So now I have two new Fathom-X in reserve.

But very happy that the problem has been solved :smiley:

Now I want to permanently connect the tether to the ROV with a 7.5mm HC WetLink Penetrator.

And upgrade some firmware in some devices….and take a test dive.

Best Regards

Erland