Pelco FS85011AMST/R fiber strangeness

[dustmop 0]

Ok, I have an issue that I have to ask for help on.

 

I have several parking lot cameras (analog, Pelco Spectra IV) about 3,500 feet away from the building, all on multimode fiber. About 5 days ago, I developed an issue with just one of the cameras.

 

It still has a nice, crisp, beautiful image. It still does it's pattern to slowly scan the area. But it will not accept user control. Again, this camera was totally functional 5 days ago. A full check of camera functionality is performed every 8 hours here, so I can say that with absolute certainty. No one has the ability to change programming of the matrix (Pelco CM9760) but me.

 

I have tried the following with no success (order may not be correct, or some steps may have been duplicated).

 

• Replaced head-end fiber receiver (FS85011AMSTR)
  
• Power-cycled the camera from the breaker
  
• Re-seated camera dome/drive
  
• Replaced camera dome/drive (address and baud were correct)
  
• Replaced camera-end fiber transmitter (FS85011AMST)
  
• Replaced control board in the housing
  
• Changed camera address at camera and in CM9760
  
• Replaced CDU-T
  
• Lots of power cycling/camera re-seating
  
• Rebooted CC1 and spare to clear any possible gremlins there
  
• Swearing at it profusely

 

Every piece of equipment involved on each end of the fiber to the other has been replaced with known working parts (I make it a point to keep working spares of everything on the test bench). Only thing I have not done is run an OTDR on and/or re-terminate the fiber. But since I'm getting a perfect image, could the fiber/ends actually be damaged? These poles do shake like MAD in the wind (cheap, flimsy things).

 

Anyone ever have a similar issue?

[hardwired 0]

If the fiber suffered damage or macrobending, there may be higher losses at the control wavelength than the video transmission wavelength (that unit is listed at 1310/1550nm operation, not sure which is the control and which is the video), so, theoretically, you could lose control but not the video.

 

Also possible that the operation is right on the edge of operation, and the transmitter/receiver pair for the control is slightly weaker than the pair for video.

 

Is the fiber directly terminated at the devices, or are there jumpers? Try changing jumpers, if applicable.

 

Either way, an OTDR check would tell you for sure.

 

BTW, I usually try "Swearing at it profusely" earlier in the process.....

[SDM Group 0]

Just a thought, did this camera change from 75ohm to hi-z in programming or vice versa.

[joelee148 0]

Hi Dustmop,

Here are several steps to identify where the issue is:

1. Connect the faulty camera with control kit, if you still get good image and could well control the camera, then the issue must be on the fiber cable or fiber converter.

2. exchange fiber Tx and Rx to another site where the camera control is working well. If it still works good after exchanged, then issue on fiber cable.

3. you can get good image but have issue on control, because control data is on 1550nm and video on 1310nm, should try to use OTDR on different fiber cables, compare the loss.

 

If confirmed the loss of fiber cable is out of nominal value, feedback to the seller, they can change a better one to you.

 

According to my experiences, you need to change a set of fiber converter to fit the fiber.

 

Hope it helps.