Focal 907 problems

[jdahl]

Hi guys,
This is my first time post on this forum, but it seems like you know your stuff.
My problem is that the video image is flickering/blinking.
It is very periodic, 16 "blinks" break for 30-40 seconds then 16 more and it keeps going.

I use Focal 907 and 10km with fiber. The Rs485, and 232 work, no problems there, so its seems like its only the video image.

any you can help me with?

johannes

[Jeremy]

Have you tried the normal culprits. Dirty connectors, Poor Co-ax connector plugs, Changed fiber ect

Do you really have 10km of fiber or is that a typo?

[Savante]

1)does this happen when the vehicle is on deck and there is little to no movement of the system?

2)Have you checked your losses through the system? Get a laser on it at the transmission end, and then track the losses through each JB.

3)What video distribution system are you using?

4)Are you connected using a single monitor to the fibre-video converter top side? (Take everything else out except for a single monitor first).

5)10 klicks of fibre is unusually large.

6) Do you have any other image artefacts coming up – does areas of brightness appear over amplified ? What camera are you using?

[jdahl]

Thanks for the reply, just read through my post, my apologies for the poor English. I’m on the test-site and time was not on my side writing that.

Zero_viz; yes we have 10km of umbilical, it’s a pipeline inspection tool.
But has a lot in common with the ROVs.

The flickering is extremely periodic when its there, so I think dirty, poor and loose of signal has to be ruled out, but yes I have checked it.

Savante;
I have measured the total loss through the hole system, it’s about 3-4 dB, so the signal is there, and the RS-482 x2 and RS-232 x2 are working perfectly.
We have two video cameras on the tool, and the problem seems to be there, because the test camera topside is not affected.
I have already tried to take the signal for the fibre-video converter direct to the monitor, still there, so it’s not the distribution system.

When the flickering appears it’s very periodic, 16 flashes, 30 second break, 16 flashes. This goes on for hours, and may stop for several hours the next day.…….

Johannes

[Savante]

You could try the following…

1. OK, unplug everything from the bottomside except the video. See if that knocks out the signal. If it does, try step 2 ?

2. two channels on an oscilloscope – overlay the voltage inputs in time from your video and try sensors in turn. Look for a correlation between the two signals – you could use this to identify the source of the problem. Also have a good look at identifying what is happening to your video signal – is it being dragged down?

3. Is this a well intervention tool or a prototype that you could post a link to? Alternatively, PM me anything non-commercially sensitive?

4. Does it happen every day? Do you (or pipeline owner) have an on-pipe communications system – thinking of something like an inductive communications system?

It sounds like it could be a transmit, wait for reply, transmit next data type signal. This is a long shot. Does it happen on deck ?

5. Is this VOIP video transmission at all ?

6. Power supply to the video camera – check it with the oscilloscope !!

7. Power supply to the bottom-side video to fibre converter !!

8. Is your test site (you never mentioned if you were in water or land) in close proximity to any Radar installations within the UK? Flash flash northwood anyone?? :lol (another longshot !!)

9. Can you screen grab an example? or post a wee video clip to the web?

10. I think you could trying to connect the centre pin from your video-fibre converter to the side of the BNC connector and see if your noise dissappears – if it’s working well you should see a good black-video image – clean. This would establish if you have something noisy in your video-fibre converter or your focal. Maybe a component is on it’s way out – optical isolator – backreflections, etc.

[Author]

Posts