OPC Factory Server (OFS) Tag Import Limitations

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OPC Factory Server (OFS) Tag Import Limitations

Note:When using a UnityPro project file as a symbol file on Windows 7, it is necessary to execute OFS with the option 'Run As Admin' enabled.

Please be aware of the following limitations when importing tags from an OFS database.

For each imported tag, the Citect SCADA tag name will be the same as the name of the tag defined on the OFS except "." characters will be replaced by "_" characters.
Using OFS tag import to import tags from an OFS database may not succeed on Windows Vista if User Account Control (UAC) is enabled. UAC stops access to the external database. If importing via OFS on Windows Vista, either turn off UAC, or right click on the OFS and Unity Pro Windows shortcuts and select "Run as Administrator".
To generate Alarm and Trend tags, a unique identifier can be set in the Custom and Comment field for Elementary Data Type (EDT) tags. For example, the string "VJA" is used to identify a tag that the user wants to use to generate a corresponding Digital Alarm Tag. Only the Comment field can be used for this feature on Derived Data Types (DDT) and Derived Function Block (DFB) tags.
OFS built-in tags are not imported. They can be added in Citect SCADA manually.
The length of the comment field in the Citect SCADA tag form is limited to 48 chaacters.
Citect SCADA does not support DDT or DFB structure types. The OFS import will enumerate each element of this type of tag and import them as elementary tags.
OFS tag import is only supported when the OFS links to the .STU and .XVM files.
DFB components of type "ANY_ARRAY_xxxx" are not imported when the OFS links to a *.xvm file. When a data dictionary is used, the data dictionary ignores comment and custom fields and therefore taggen cannot generate alarm and trend tags. If there are DFB components of type "ANY_ARRAY_xxxx", the whole DFB is not imported.
The following table shows data types supported by the tag import and TagGen when the OFS links to *.stu or *.xvm file.

	OFS links to *.stu file			OFS links to *.xvm file
	Tag Import	Tag Gen		Tag Import	Tag Gen
Data Types	Tag Import	Comment Field	Custom Field	Tag Import	Comment Field Only
Elementary Data Types (EDT)
BOOL	Yes	Yes	Yes	Yes	Yes
EBOOL	Yes	Yes	Yes	Yes	Yes
BYTE	Yes	Yes	Yes	Yes	Yes
INT	Yes	Yes	Yes	Yes	Yes
DINT	Yes	Yes	Yes	Yes	Yes
WORD	Yes	Yes	Yes	Yes	Yes
DWORD	Yes	Yes	Yes	Yes	Yes
UINT	Yes	Yes	Yes	Yes	Yes
UDINT	Yes	Yes	Yes	Yes	Yes
REAL	Yes	Yes	Yes	Yes	Yes
STRING	Yes	Yes	Yes	Yes	Yes
DATE	Yes	Yes	Yes	Yes	Yes
DT	Yes	Yes	Yes	Yes	Yes
TIME	Yes	Yes	Yes	Yes	Yes
TOD	Yes	Yes	Yes	Yes	Yes

Derived Data Types (DDT)
EDT in DDT	Yes	Yes ²	No	Yes	Yes ³
Array in DDT	Yes	Yes ²	No	Yes	No

Arrays
Array of EDT ⁴	Yes	Yes	No	Yes	No
Array of DDT ⁴	No	No	No	Yes	Yes ¹

Function Block Types (FBT)
Elementary Function Block (EFB)	Yes	Yes ²	No	Yes	Yes ³
Derived Function Block (DFB)	Yes	Yes ²	No	Yes	Yes ³

Synchronization
Live Update	No	No	No	No	No
Automatic Refresh of tags	No	No	No	No	No

Only the BOOL type tags in the DDT can be used to generate Alarm and Trend tags when the OFS links to the *.xvm file.
When OFS links to the stu file, the comment string defined in the tag instance will be taken, the comment string defined in the DDT/DFB definition will be ignored.
When OFS links to the xvm file, the comment string defined in the DDT/DFB definition will be taken and the comment defined in the tag instance will be ignored.
Array with negative index is not supported.

Published June 2018