Siemens S7 Address Question

Using the Ignition Siemens S7-400 driver (version 7.7.5). I can successfully read address types such as Input Words using an opc item path such as “[device]IW0”.

However, I am having issues reading data block addresses.
For example, the PLC has data in address DB40.DBD8

I have tried several formats in the OPC item path with no luck.

[device]DB40,DBD8
[device]DB40,D8
[device]DB40.DBD8
[device]DB40.D8

What am I missing?

[device]DB40,D8 should work, assuming you’ve got the right data block number and offset.