Issue addressing Siemens Instance DB in Ignition

Ignition
1

Hi all,

I'm trying to access a tag in Ignition which comes from an Instance DB in a Siemens S7-1500 PLC, and for some reason it is not working.

If I access a global db it works fine.

For example: DB200 is my instance DB, and DB8 is my global DB.
If I put the opc item path as: "ns=1;s=[S71500_PLC]DB200,W0" it doesn't work (Quality bad), but if I change it to "ns=1;s=[S71500_PLC]DB8,W0" it reads the value correctly.

What is the issue here? Thanks.

2

Only global DB can be accessed if I remember correctly.

3

Maybe try this one

4

You can access instance DB also, at least I can on my PLC 1500:

Screenshot_117
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Screenshot_118
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Screenshot_119
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but you must disable "Optimized block access" ...

2 Likes
5

I solved it 30 min ago. The issue in our case is that when the project got migrated, the "Optimized block access" got ticked. Once I unticked it, it now works.

Thanks everyone for the help.

6

Yes. During testing we had it configured like this. But I then migrated it, and not sure how the optimized bit got ticked.

Thanks