Reason for garbage values in serial communication..

I need some guidance from you because am facing the problem in RS485 communication, its works fine but additionally some of the garbage value will received. i don't know how to solve the issue. For 485 communication am using ADM2587 transceiver IC.Even though am controlling the drive enable and receive enable pins in software for proper communication but garbage occurred . Kindly give me a suggestion if i want to do anything in hardware.

Hi,Santhosh kumar,

I had faced a problem during an installation work in the railway ticketing machine
when i was working for keltron. The communication port was 485 it made lot of
errors in the data, .problem was with the power plug check the neutral to earth voltage it
should not be allowed to go above 4v if above that it can even damage your
communication ic.check all the plug points you are using , secondly check the shield
wire of your communication cable for loose , open or dry soldering.

Regards Sambath kumar.

HI Sambath Kumar,

Thanks for your information sir, I checked the power lines there is no issue and also in communication cables shield wire is connected to ground. Even through the problem is present. Is there any other options to solve the issue in hardware/software. i think its purely in hardware. Kindly give me a suggestion.

Regards,
Santhosh kumar.

Hi, Santosh kumar,

since your power socket connections are correct ,
1. problem is with your TXD & RXD wiring connections for any dry soldering or interment
loose connection ,check the termination resistors of TXD and RXD cable wiring
at the master and slave end for open or loose contact. dont ground both ends of the shield
wire of your communication cable to ground ie means only one end of your communication cable end should be grounded. ADM2582E is an equilent ic. this is for your ref information.

2.check dry soldering of capacitors coming(2 no in parallel 10nf and 100nf ) on
pin no 1&2, 9&10;, 11&12;, 19 &20; of ic ADM 2587 any how this is a rare case.

your problem will be solved by point no1.

Regards
Sambath kumar

Hi Sambath kumar,

Thank you once again for your replay sir really your guidance is help full to solve the issue. Actually only thing i didn't isolate in the receiver side otherwise all the parameters i verified like termination resistor,cable connection etc. Finally i isolate the master and slave connections then the problem is solved...

Regards,
Santhosh kumar.