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Modbus read builder...?


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Dear All,


 searched in the forum but I don't found what I need...and I can't insert a pic of the "question"..I can upload only 29.9 Kb!
I tried to use the element "modbus read builder" to read a lot of registers together...
in the point "A" I insert an "modbus request" with: protocol=0; function n°=3; slave ID=1; start address=0; number of operands=39; ethernet trns.= nothing.
in the point "B" I insert a BUFFER (that I created in GLOBAL tag) with 8 "array".
In the point "D" I insert a "modbus request descriptor" with: expected response=43 (I have read it after the first test...and is what I expected...if I have understood the modbus RTU protocol); protocol=0;function=3; start address=20; number of operands=19; ethernet=nothing.
For the point "C" (request size) I tried different "tag" (buffer, int,uint..) but nothing seems work!
When I tested the "program" I have had the following response from the buffer in the point "B": 1,3,0,0,0,39,5,208.
in the tags that I tried to use for the answer (it is an answer?) I have always "0" in each point...
What I have to do?
thanks in advance


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Dear All,


yesterday I have downloaded the last sample programs from the site and I understand that I really wrong everything...please accept my apologise if I have wasted your time with my uncorrect question...I am less then a beginner and I have learn more...now I know that I have to insert a tag with indicate the array lenght in the slave session and what I have tried before is for the TCP.
I hope next time my question will be done in a properly way.
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