Cabling

[premkumar9]

Hi,
I have to drive LED signal lights. I consider three methods .
1) Connecting the Signal Lights with separate cable for each light. Here full load current will flow through the connecting cable. So higher cable size to reduce drop.
2) To keep the drivers (FETs) near the Signal light and take the Gate drive through cable. Here smaller cable size is enough. But I doubt about noise pick ups.
3) Use a Microcontroller and drivers near the Signal Lights and send the required signals through TXD, RXD pins from the main unit. Here I can save cable.

Can anybody pls comment on this and give suggestion?

 

[kchriste]

The answer depends on many factors:
How far is the wire run?
Where is the power source located?
How many separate lights need independent control?
How much current per light?

 

[Mikebits]

How much power could possibly being going through this cable to make you worry? How much I²R losses are we talking about here? I do not see why you could not use a bundled wire cable to carry your signals.

 

[premkumar9]

I do not see why you could not use a bundled wire cable to carry your signals.

Definitely I can. But trying to save the cost.

 

[Mikebits]

In that case, how about an I2C interface?

 

[premkumar9]

In that case, how about an I2C interface?

That is the most cost effective method in my opinion. But it has to be error free. I had tried it in lab. But liked to here the opinion of people with practical experience before implementing.

 

[Nigel Goodwin]

Why I2C, are you using I2C chips in the design?. I2C is a very short range (intended for use on a single PCB) system for interconnecting IC's - developed for use in TV sets. Why not just send RS232?.

 

[premkumar9]

Why I2C, are you using I2C chips in the design?. I2C is a very short range (intended for use on a single PCB) system for interconnecting IC's - developed for use in TV sets. Why not just send RS232?.

Sorry, I only meant MC to MC communication through TXD, RXD through RS485 cable and driver.