800xA Logs DCI module PAR
I will log the tag.atom 24PAR1.V1 (24PAR1 is a PAR's module for DCI).
I can't select it because the format is VT_BSTR.
I can't select the atom VAL because the format is ARRAY.
Have you a solution or an idea?
The History Services cannot log part of an array. ( Array support in OPC is quite patchy, the 800xA servers dont really support arrays very well, if at all )
You would need to extract the required item from the array in your controller and subscribe a tag from 800xA to that value.
For this reason, the DCI Connect consider them as VT_BSTR.
If I extract the data, I store result on a module PAR and I have the same problem.
On 800xA, can you convert or force the format (perhaps with a other aspect) before to log it on History Services ?
Thanks for your answers
To acces a single element of a an array (for example, you got the array FG) you have to manually add it to the control connection as a new atom. If you want to acces FG, being FG an array, you've got to add FG (just like that) and then read/write directly that atom, instead of trying to read/write the FG and select one of its elemments.
In the control connection you would see (after adding the missing atoms you needed) something like this: