ControlLogix 5550 buffer size

M

Thread Starter

mubs_tvm

I am trying to read a tag from ControlLogix 5550 which has a size greater than the buffer size of the PLC(511 bytes). Im using the CIP protocol for doing the read. Is there any method by which i can read the tag in one single instruction ? If i need to read the tag using multiple reads, can we do the same via CIP ? As far as i know, we can read a particular element of an array tag using CIP, but i did not find any documentation that says that i can read a range of elements in an array tag using a single read command. I certainly appreciate any pointers in this regard.

Thanks.
 
S

ScienceOfficer

Mubs---

You're on the right track, but you aren't going to get around that 500 byte limit for one tag with one instruction. Tips for accomplishing your goal--- moving a large chunk of data--- are in Chapters 14 and 15 of the Common Procedures manual, which you can view at

http://www.ab.com/manuals/cl/1756-pm001e-en-p.pdf

Hope this helps!

Larry Lawver
Rexel / Central Florida
 
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