Micrologix Tag Addresses

Can someone please explain to me the addressing of the Micrologix tags? I have the OPC Browser and the SQL Browser along with the tag list for a project. I am wondering how Ignition views the tags. I already figured out that I have to manually add the subtags, but, I need an understanding of them.

Even if someone could point me to a link that I can get educated on tag addressing and how it works?

[attachment=0]OPC compare.jpg[/attachment]

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this is probably a good place to start

literature.rockwellautomation.co … _-en-p.pdf

basically the first part I: is the datatype
the 2nd part is the slot in the rack. In micrologix all have on board so those would be 0 then added cards would be 1,2, etc
the 3rd part is the bit or channel.

so 2 examples

your turn main on tag would be the 2nd digital input on the micrologix controller

your alarm silence would be the 6th digital input on the add on digital input module.

When looking at the specs for the design, the POC Main Valve is I:0/19 but when looking at the OPC Browser, it only goes to I:0/15. I was doing some reading about this, but didn’t understand it. Google is so confusing. If the I/O has 16 slots, how do they go higher?

oh ok, I see what you are saying. If you have the logic and look at the data file, which is essentially what you are seeing in the opc browser, inputs 16-19 get thrown into the next set of 16 bits, which would fall under I:0.1. I am assuming that the controller automatically routes any request for I.0/16 to I.0.1/0. If you look at the attachment, The address for I.0.1/16 is listed as I:0/16.

Thank you… that explains what I was looking for. :slight_smile: