Ken Roach
Lifetime Supporting Member + Moderator
I consider myself an expert programmer with ControlLogix, but yesterday I started my first application with Red Lion Crimson 3 using String tags in ControlLogix.
As with many things in Crimson 3, it's clear once you know what to look for, but the learning curve can be steep. It took me a few hours to get my head around how this works.
I learned that only the 'Native Tags via L5K' driver supports String datatypes in ControlLogix, and I experimented my way into understanding how Crimson 3 handles padding, text justification, and writing the Length element.
The most important thing to understand is that a Crimson 3 String Tag is associated only with the ControlLogix StringTag.DATA sub-element array, which is a SINT[82] byte array. Don't attempt to point the String Tag at the whole String datatype, because it handles the length based on your definition in Crimson 3, not by the value of the .LEN sub-element.
I wrote up the results and am attaching them for my own future reference, and so they can be helpful to users searching this Forum.
As with many things in Crimson 3, it's clear once you know what to look for, but the learning curve can be steep. It took me a few hours to get my head around how this works.
I learned that only the 'Native Tags via L5K' driver supports String datatypes in ControlLogix, and I experimented my way into understanding how Crimson 3 handles padding, text justification, and writing the Length element.
The most important thing to understand is that a Crimson 3 String Tag is associated only with the ControlLogix StringTag.DATA sub-element array, which is a SINT[82] byte array. Don't attempt to point the String Tag at the whole String datatype, because it handles the length based on your definition in Crimson 3, not by the value of the .LEN sub-element.
I wrote up the results and am attaching them for my own future reference, and so they can be helpful to users searching this Forum.
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