Legacy ControlLogix tags are coming in with BAD quality

Good morning,

I have established communication with a ControlLogix PLC running 20.19 firmware using Ignition’s Legacy AB driver. The Gateways shows the PLC as connected.

I can see the tag values in RSLinx.

I can browse the tags in Designer and drag them into the Tag Browser, but all the values are BAD.


The diagnostic page for one of the tags shows valid tag definition and tag group.

Any ideas why the values are not coming through?

Thank you,

With 20.19 you need to use the Allen-Bradley Logix Driver (v21+)

1 Like

@Tim is correct, and we’re going to be updating the descriptions of the drivers to make this more clear.

Last week we loaded various firmware versions onto a controller here and confirmed that the legacy driver works through v20.18 but in v20.19 they disabled direct memory access (AND they did not implement instance-based access either, so it’s a truly worst-case version to be on performance-wise).

1 Like

Thank you very much for the quick solution :smiley: