RS232 data read

[Joe Tauser]

Now it's programming fun time.

See my previous post.  Try stacking them up by adding the incoming number to a buffer.  If the buffer wasn't 0, multiply it by 10 before you do your addition.

Joe T.

[Tara]

Hi everyone,

I'm getting in trouble with RS232 scan protocol

Is there any way to prevent the "index of received  message" from turning -1 when an incorrect message has been received ?

Tara

[Joe Tauser]

Create an entry in your scan table of one big Stream type variable that will be larger than any message you anticipate receiving.  When something comes in that doesn't match your other entries it will land there-

 

 

I find the pre-defined string / variable entries in the Protocol Scan block to be extremely unpredictable.  I do almost everything with a general-purpose string receiver (as shown above) and then sort it out in ladder logic.  It's a little more complicated to do it this way but a lot more robust.

Joe T.

 

 

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[Tara]

Thanks to you, it seems to work. But I have a question: Does the "incorrect message" when it appears can make my index MI3 equal to 9 or will it only affect MI900?

I tested it and it doesn't make MI3=9, but I want to make sure that it won't happen.