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Error in RS 485 Communication for 1000 meter range

GOPAL jadhav
Prodigy 50 points
Other Parts Discussed in Thread: SN65HVD05

We are used Straight cable for RS 485 communication (not twisted pair ) for 1000 meter 

what should be the proper designing method of RS 485 communication for longer distance (more than 1000 meter)

Basically We are implementing RS 485 communication protocol for Marine application but problem is very huge noise  environment in that Ship due to that our system get some time hang ,reset,communication fail,driver get damage.

But now we are design new hardware for that which is Isolation of Power Supply & Data with the reference of TI then also we are facing same problem which mention above

Please give best solution 

Reply must

  • 0
    Prodigy 50 points

    1>I want standard Module Isolation Power Supply & data which is having in built isolated transformer ?

    Is there any such module is there please send me part number

    2>for longer distance is there any need of booster or repeater ?

    If it is need so which kind of module there

    3> data get lost because of bending of communication wire ?

    4>We are already install straight cable(not twisted pair ) so write now  it not possible for changing the wire 

    so please give best solution for that

  • 0 in reply to GOPAL jadhav
    TI__Expert 5400 points

    Hello,

    A bit more information about your application would be helpful to determine the best solution.

    • What is the data rate?
    • How many nodes on the bus?
    • Are you using standard 120ohm termination?
    • Can you specify which TI reference you have been using so far?

    As you mention, using shielded twisted pair cable would offer obvious improvement.  A few other options come to mind that could improve your success rate.

    1) Add common mode filtering by replacing each 120ohm termination resistor with 2 60ohm resistors with a capacitor from the midpoint to ground.

    2) Using RS-485 transceivers with larger VOD, such as SN65HVD05 or SN65HVD3082.

    3) As you mention, implementing an isolated RS-485 repeater, for which the following app notes may be useful: