some problem regarding est-3 network card rs485

[Eagle00708]

Describe the problem, what is happening, I have not had a specific issue but I have had problems with high power two-way radios

[junjun]

the issue is..when there is sudden surge on power supply like diesel power generator its damaging the network card..why not the power supply?

[Eagle00708]

Does the 485 card go completly bad or does the network just go down and come back up. Must be an old generator because we have several building with backup diesel generators and if they are wiping out panel parts then the generator has some major issues. The reason for the first question is because it may be more of an EMF issue depending on how the network cabel is ran.

[Leo]

it sounds like an EMF thing, is the network cable shielded?
almost always it's because we used shielded cable that we had a problem, I know they say use shielded cable to stop EMF but it sames to be the opposite.
If you are using shielded cable ground only one end.
- try a surge protector designed for a rs485 line, it works great the stop lighting problems.( both ends )

[junjun]

yes the card was fried up..the network cable is shielded and is free from earth fault..i think this is the weakest part of the est-3 panel..

[Leo]

one end of a shielded cable needs to be grounded.
If a shielded cable is not installed right it will be a bigger problem then if non-shielded cable was used.
I would look into the shield and play with that.

[Eagle00708]

A cable shield problem would cause communication issues however a completly burned up fried 485 card means there is something wronge in the field. At this stage in the game it would be best to run a temp cable on the ground and do several simulated tests this will help eliminate EMF/Field wire as the Problem

[junjun]

well im talking about a mall having a 43 est-3 panel..pulling a temporary cable i guess is not a good option..has anyone tried here fixing an isolator module on the network?

[Leo]

how many times has this happen?
It maybe a lightning problem, shielding makes lightning problems worse.
I would think about lightning suppression, the few times I have used they it has made a bad problem just disappear.
get the right type (data rs422/485) its a low voltage type.
If this is that big of a problem I would just put them, at least at the worse panels.
and if it is not lightning it still may fix the problem.

[junjun]

it happens when there is power interruption on the area...i will check the spec's of that lightning suppression..thanks