Probing for Tags

[nisargpandyadattus]

Hi, Is there any facility available like probing in which we can query for tags from the PLC directly to get to know which are the tags configured?

[pjkundert]

Nope. Like every other part of the protocol, we'd need to sniff the activity using Wireshark, and then reverse-engineer the protocol elements used. Not documented, in any of the thousands of pages of documentation that I've read.

[kyle-github]

It turns out that AB does document this. In their own "special" way. I got this from a user of my library and I thought I would pass along the joy for the season:

Logix5000 Data Access Programming Manual

Have fun. I love that the tag instance numbers come back in 32-bit quantities, but you can only use 16-bit instance IDs when requesting the next batch.

[kyle-github]

Attribute 7 gives the size of one element and attribute 8 gives the array dimensions (all 3 at once each as a u32).

[pjkundert]

Thanks for that! I'll have a look. Pull requests accepted!!