AB PLC AOI Local Tag Accessibility

[Nan]

Good evening all,

I have a question regarding AB AOI and wonder if anyone can help me.

I am in a production environment so I can not change the AOI and apply. But is there a way that I can access the local tag without changing anything on the OI? The local tag data type is string [16].

Thank you!

 

[ASF]

No.

If the Local Tag external access is set to Read or Read/Write, then a HMI or SCADA system can access it. But the PLC logic cannot access AOI local parameters

 

[JeremyM]

You can have the controller send a CIP data table read message to itself. As ASF said, the local tag needs to be Read or Read/Write to be accessible, as well as the AOI instance. This gets PLC logic access.

If you are looking to change their values by hand in Studio, you can monitor local tags and change the context to the AOI instance.

 

[Aardwizz]

Maybe, kinda, sorta.

What you can do is, outside of the AOI, COP the AOI tag to a DINT array tag with the same byte length as your AOI. Look at the AOI data type to get that value.

There will be some place in the DINT array where the string you are interested in will start. If you are using Radix to find the text of the string in the DINT array, keep in mind that the .LEN field is first, so if the AOI has string "HELLO WORLD", and you see "HE" in DINT[48] and "LL" in DINT[49], then your string starts at DINT[47].

COP DINT[47] to another tag that's the same data type as the one in the AOI (e.g., "String_16" or whatever its called), and that new tag will have your target string.