RSLogix 5000 serial data reading problem.

Hello everyone, this is my first time asking for help here, so please bear with any problem my english or lack of experience can cause.
i have a little problem with the serial reading on RSLogix 5000.
My project basically is a microcontroller connected by serial to my PLC L32E, i first send from the micro 3 strings of 17 chars, after those i send an array of the first three in one longer string, with the first 3 ones there is no problem, but after sending the last one, it adds characters of $$ to the end of the line, sometimes in the middle of the string appears $$$ or even $00, which cause the buffer to stay with a query of 2, and that misplace the next lines incoming, that extra characters appears at random, and since i am using ARD it is causing a lot of problems.

i read the manual of the rslogix about configuring the serial connection, the instruction help of the commands and still cant figure out what is the problem.

Welcome to the forum.

The first thing that comes to mind when troubleshooting serial ASCII connection is to segregate and trace down the origin of the problem. Have you tried to connect the micro-controller to your computer's serial port running something like PUTTY or Hyper-terminal to see if the data is showing up good?

Some thoughts,

If you are able to send over the 3 strings correctly, why bother to send over the 3 combined? I think you can combine them in the logix.

Also, when you mention $00, are you seeing that in the value box of the ASCII.DATA field? If so, that simply means a null character ('$00' - as in hex value of 00) and it's most likely how your micro-controller's way of separating the 3 strings.

You will want to go to Tag Monitor and examine the string character by character.

hi harry, first, thanks for your help.

i tested the code first with a software similar to Hyperterminal, and there it sends it correctly, is when i send it to the PLC that the problem starts, in the ASCII.DATA i checked that all the characters were there, and indeed they were there, but because of the other characters that i didnt expect, it mess up the lenghts.

i use EQU with the .POS of the ACB to trigger the ARD, but after the ARD ends, sometimes it leaves 2 chars in the buffer, so the following strings add those remaining 2 and it misplace all the characters.

about combining them, i know that it is fair easier because by some reason the first three separate strings come clean without sending the long string after them,but the problem is that it is a requisite for the project to send, read and save that long string :S