Interferance with 7 Camera PTZ system on a Gas Plant

[ouija 0]

Hello,

 

Recently I helped to install a 7 camera PTZ systems with a DVR unit on a new gas processing plant being built.

 

Everything was working fine until a few days ago, when they began bringing the majority of the plant's equipment online and now the 4 cameras closest to the "inside" of the plant all have some type of interference happening, where the picture has snow or static happening in it.

 

The plant has gone offline recently and the interference disappered, but once they bring all the equipment back online it comes back.

 

We are using 120v power with passive video baluns to CAT5 unshielded twisted pair to all cameras, but have also tried re-running a camera using 18/2 shielded cable as well, both of which suffer from the same interference.

 

I have tried using ground loop isolators for the video signal with little to no improvement. Recently, I opted for a better model of isolator with noise filters built in and am waiting for them to arrive to test. However, I need to cover my bases in case this doesn't help.

 

My question is if anyone on here has ever experienced any type of interference similar to this and if anyone has any suggestions to solutions or ideas to eliminating this problem.

 

Could is possibly be a "dirty power" issue and would an inline power filter help? something similar to this perhaps? http://www.automationdirect.com/adc/Overview/Catalog/Power_Products_%28Electrical%29/Power_Line_Filters;jsessionid=5e30175972762ee594465b4821315a3d2625?source=google&keyword=EMI%20line%20filter&type=search&gclid=CKL-n4ngv6gCFSYZQgodURXYqQ

 

I've read that these can help eliminate EMI and RFI so I'm hoping they might help. However, I'm worried that something might be directly interfering with the cameras themselves, or would it possibly still be through the video cable itself? Most of the cameras are running about 700ft cable lengths to them, and let me remind you that this is a gas processing plant so there is all type of compressors, pumps, valves, electrical runs, lines, etc. The cables runs with various other cables in outside trays throughout the plant.

 

If anyone has any questions, suggestions or solutions how to remove and troubleshoot interference issues then I am all ears! Any help is GREATLY appreciated!

Edited May 3, 2011 by Guest

[Soundy 1]

Some screenshots or even video of the interference might help diagnose whether it's EMI, RFI, or ground loops, as all tend to manifest a little differently.

 

Is it possible to do some further troubleshooting by turning various equipment on and off in stages while seeing how various cameras are affected? It might be possible to narrow it down to some particular equipment or a particular area that's generating the interference.

 

Does the interference happen the same on all cameras at the same time? That might help determine if it's coming from a point common to all of them (ie. somewhere that ALL the cables run past).

 

MuxLab has a good document on baluns here, it includes some "best practices" suggestions for running cabling, including distances from power and equipment: http://www.muxlab.com/assets/files/application_guides/VE_CCTV_Balun.pdf

[survtech 0]

Where is/are your camera power supplies? You might try isolating it/them from where they are plugged in or use a filter.

[Nimrod 0]

“We are using 220v power with passive video baluns to CAT5 unshielded twisted pair to all cameras, but have also tried re-running a camera using 18/2 shielded cable as well, both of which suffer from the same interference.”

 

Do you mean you ran 18/2 shielded cable for power with your cat5 for video. Or do you mean you tried Siamese RG59U coax for video with 18/2 for power.

[ouija 0]

Some screenshots or even video of the interference might help diagnose whether it's EMI, RFI, or ground loops, as all tend to manifest a little differently.

 

I will try and take some pictures of the on-screen interference if possible, however cameras are not allowed on site by client request but I will try and get them to make an exception in this case.

 

Is it possible to do some further troubleshooting by turning various equipment on and off in stages while seeing how various cameras are affected? It might be possible to narrow it down to some particular equipment or a particular area that's generating the interference.

 

Nope. Unfortunately we do not have the clearance to either turn off or on any other equipment in the plant other than anything to do with this camera system. We are certain it is some type of equipment in the plant causing the interference but what it might be is still a bit of a mystery.

 

Does the interference happen the same on all cameras at the same time? That might help determine if it's coming from a point common to all of them (ie. somewhere that ALL the cables run past).

 

Yes, it appears to be affecting all 7 of the cameras, however the 4 cameras closest to the plant are the ones that are most affected.

 

Where is/are your camera power supplies? You might try isolating it/them from where they are plugged in or use a filter.

 

Update (from one of our installers): the cameras are being run on 120v a/c, they have a 3 conductor #12. the 12/24 volt is ran on an 18/2 for camera 1 and the others are on the cat5 cable

 

Do you mean you ran 18/2 shielded cable for power with your cat5 for video. Or do you mean you tried Siamese RG59U coax for video with 18/2 for power.

 

We can CAT5 for the video to 6 of the cameras, and one camera is using 18/2 shielded for the video.

 

 

 

 

Any thoughts?

Edited May 3, 2011 by Guest

[Nimrod 0]

First, if the PTZ is connected to anything conductive, disconnect it and screw it to a plastic isolator. Also make sure that there is no ground wire connected to the camera and what it is mounted to.

 

Next, try an experiment isolating the power. The ideal way to do this is at the PTZ location disconnect your remote power lines and power the camera with a large battery.

 

For the last experiment hopefully you have an easy way to try a quick run of RG59U to the camera to see if that clears up the problem even if you just have to lay it on the ground. RG59 has a much greater noise immunity than cat5.

[Soundy 1]

Ummm... wait, the cameras are all powered directly with 220VAC? Does that mean they have internal power supplies? Most cameras require 12VDC or 24VAC.

 

I don't think 18/2 is legal for running 220VAC on, either.

 

As far as screenshots, can't you just export some stills from the DVR? Some exported video clips would probably be even more useful.

[survtech 0]

18/2 could be used for 220VAC if the insulation is rated for at least 600V, however, it is probably not wise to do so without involving a certified electrician. If the cameras are powered directly from 220VAC, that can cause a slew of problems, including ground loops, etc. due to lack of any type of isolation.

[ouija 0]

Sorry guys,

 

I was mistaken; The cameras are being run on 120v a/c, they have a 3 conductor #12.

 

Could using an inline power filter help this situation any? I am going to attempt using some ground loop isolators with built in filters to see if they make a difference, along with active video baluns instead of these passive ones.

 

Thanks again, and my apologies for the misinformation. These cameras have been wired in by a group of certified electricians that have clearance on site, and I am unfortunately relaying information back to them on what the possible issues might be, so I cannot obtain pictures or stills directly.

 

Yes you can take stills with the DVR but again I am unfortunately not on-site to do so, and do not feel comfortable instructing one of these electricians to do so as they have little experience actually using the DVR unit itself; However they are going send me some photos of the viewing monitor as soon as possible.

[survtech 0]

Are they all on the same circuit or do they each connect to separate circuits?

[ouija 0]

Are they all on the same circuit or do they each connect to separate circuits?

 

The are all connected to the same circuit and we have tried using a ground loop isolator in case that was the issue and it didn't seem to help; I am going to try using a different unit with a built in noise filter to see if that helps.

 

My brother (a master electrician) seems to think it is an issue with the video runs themselves, possibly because of the unshielded CAT5 getting interference from something.

 

However, I thought using shielded is not recommended for long distances as the shielding can actually cause interference as well (most of the cable runs to each camera are 700ft or more) and so if this is the case would my only option be looking into using fiber optic instead? (providing that using these ground loop isolators on the video runs and power filters on the a/c connections don't help)

 

He was also telling me that the cables should be ran with a 600mm or two foot space between any power cable or wires or have a barrier bonded to a ground between them. We will need to double check our cable runs, but I don't believe the video cable is running along any powered wires.

 

Thanks

[BCMPROSOLUTIONS 0]

Run a dedicated isolated ground for your 120vac line that all your equipment plugs into (orange wall plug and a copper rod into the earth)

 

Cheers

[Soundy 1]

I'm still not clear on the power here... the cameras are wired directly into the 120VAC without a transformer or power adapter or central power supply?

 

The MuxLab document I linked to above has some recommendations on running UTP with regards to proximity to power and EMI sources; check it and compare to how things are set up.

 

Running unshielded should not be the problem - the whole point of using baluns (short for BALanced/UNbalanced) is to create a balanced line that inherently rejects noise. Again, there are diagrams in the MuxLab document that explain this.

 

At 700', you MAY need to use an active balun at one end of each run... wouldn't hurt to try one, anyway, and see if it helps things.

[ouija 0]

I'm still not clear on the power here... the cameras are wired directly into the 120VAC without a transformer or power adapter or central power supply?

 

Sorry for all the confusion. I am not directly involved with the wiring of the system being that I do not have clearance to do so on site, so I am simply relaying all the information passed to me by the electricians on site.

 

My understanding is that all 7 cameras are directly connected to 120VAC which all feeds back to the same circuit / panel. There are no a/c adapters or anything being used as far as I am aware.

 

We are using the Ranger - Outdoor 300' Night Vision High Speed PTZ Camera, and the manual can be found here:

http://www.mediafire.com/?t9052o1sa6u2pj2

 

The spec sheet for the CAT5 cable being used can be found here:

http://www.mediafire.com/?4e2yp4412oxf6ff

 

The manual for the DVR unit can be found here:

http://www.mediafire.com/?wd9hcc5iyp6obc9

 

Some (rather poor) pictures of the interference seen on the viewing monitor can be found below:

http://i.imgur.com/JWtPA.jpg

 

http://i.imgur.com/6hH29.jpg

 

Any thoughts?

 

Update: One of our electricians just informed me that they are using shielded CAT5 now and there is still this interference issue. Providing that the grounding is adequate the shielding itself wouldn't aid this interference somehow would it? I would think it should help... but need to ask

[Nimrod 0]

“We are using the Ranger - Outdoor 300' Night Vision High Speed PTZ Camera, and the manual can be found here:

http://www.mediafire.com/?t9052o1sa6u2pj2“

 

The download has errors and i cannot open the PDF.

[Guest]

I'm still not clear on the power here... the cameras are wired directly into the 120VAC without a transformer or power adapter or central power supply?

 

Sorry for all the confusion. I am not directly involved with the wiring of the system being that I do not have clearance to do so on site, so I am simply relaying all the information passed to me by the electricians on site.

 

My understanding is that all 7 cameras are directly connected to 120VAC which all feeds back to the same circuit / panel. There are no a/c adapters or anything being used as far as I am aware.

 

We are using the Ranger - Outdoor 300' Night Vision High Speed PTZ Camera, and the manual can be found here:

http://www.mediafire.com/?t9052o1sa6u2pj2

 

The spec sheet for the CAT5 cable being used can be found here:

http://www.mediafire.com/?4e2yp4412oxf6ff

 

The manual for the DVR unit can be found here:

http://www.mediafire.com/?wd9hcc5iyp6obc9

 

Some (rather poor) pictures of the interference seen on the viewing monitor can be found below:

 

Any thoughts?

 

Update: One of our electricians just informed me that they are using shielded CAT5 now and there is still this interference issue. Providing that the grounding is adequate the shielding itself wouldn't aid this interference somehow would it? I would think it should help... but need to ask

 

Have checked the video output directly out of the camera with a test monitor?

 

This will indicate if the problem is with power or the transmission system.

 

Ilkie

[ouija 0]

The download has errors and i cannot open the PDF.

Strange, just tested and works for me. Here's a mirror:

http://www.megaupload.com/?d=MU2CTNHC

[ouija 0]

Have checked the video output directly out of the camera with a test monitor?

 

This will indicate if the problem is with power or the transmission system.

 

Ilkie

That is a brilliant suggestion! However, this plant is in a remote location and they unfortunately do not have any test monitors on site. I suppose I could try and get one sent out to them....

Very good suggestion however, thank you.... embarrassed I didn't think of it...

[Nimrod 0]

I did get the manual now, and it says the power to the camera should be 220 volts.

 

You said all the cameras were run back to the same power panel, what about the DVR, does it go back to the same panel.

 

And i still think the camera case should be electrically isolated from what ever it is mounted on.

[Soundy 1]

That first photo looks like motor noise of some kind - not what you'd get from running too close to power lines, but what you'd get from running too near an electric motor or something of the sort. I've also seen similar interference from RFI caused by a car's ignition system, but since the noise follows the operation of some equipment, I doubt that's the case here.

 

Actually, my uncle used to have a CB radio in his Jeep that would cause similar interference on a certain TV channel when transmitting on a certain CB channel... does any of this equipment use RF-based controls or telemetry?

 

As a troubleshooting step, I'd see if it's possible to have them create a log (if there isn't already) of the operation of various different equipment, and then correlate that to the noise on the recorded video, and see if anything really jumps out - for example, if you look a the video and find a jump in noise level at 6:15pm, you could then check the logs and see what systems were turned on at 6:15.

 

STP for the wiring wouldn't make a substantial difference, I don't think... again, a balanced line has inherent immunity to noise on its own. Nevertheless, it IS important that it be grounded properly... that means grounded at one end only, and make sure it goes to a good earth ground.

 

The test monitor is a good idea... another good way to test is to take a camera near the DVR and plug it in directly, to rule out noise getting into the DVR itself.

[ouija 0]

I did get the manual now, and it says the power to the camera should be 220 volts..

Sorry! I mislead you yet again... grrr... this is a PDF I received from the sales rep for the previous years model; The version we have actually supports 120vac (I'll post a copy of it once I can)

That first photo looks like motor noise of some kind - not what you'd get from running too close to power lines, but what you'd get from running too near an electric motor or something of the sort.

There could definitely be some type of motor operating somewhere - how could we avoid this interference?

 

I will ensure it is grounded properly and will keep trying to figure out where the issue might be...

[Soundy 1]

First thing you'd have to do is find the source of the interference... then if possible, the best option would be to move the cable runs further away from it (like I say, it's also possible that the interference is getting directly into the DVR - try narrowing that possibility down as well).

 

If that can't be done, you may be able to shield the wire more by putting in through conduit in that area.

[Nimrod 0]

“If that can't be done, you may be able to shield the wire more by putting in through conduit in that area.”

 

Just to be clear, Soundy meant metal conduit, This would act as a shield to electrical interference.

[Soundy 1]

Right, that's what I meant. Thanks for clarifying

[Bunited2 0]

Wow lots of good info from you guys, surprised he would still have any issues.

 

I would get an inverter ($ 29.00) plug into a cigarette lighter (to get 120 vac locally) of a vehicle and power a (problem) camera at the location to completely isolate if a power problem.

I actually agree with electrically isolating the casing, physical grounding of the camera itself. High voltage systems are (not in all cases but some) do not use earth ground

for grounding, thus the power to equipment and structures will/could be a different potential.

Also, there is a difference of inserting V ground isolation transformer at the video source and at the home location. An isolation transformer should not help with signal over a twisted pair, but a twisted pair should not experience interference anyway.

Judging by the pictures (w/o seeing them moving is difficult to see) but it almost looks more like a ghosting problem...?

My guess would be (since most cameras are affected) a power problem. Along with powering separately like I said, I seriously think the plant power is not inducing emi interference, but dirty power interference/noise.

 

Bunited2