Applies To:
  • CitectSCADA 5.00

There have been some problems reported with ctTagToPoint. Can you outline what they are. 

There are problems with the CtAPI function ctTagToPoint. The parsing routine on the Citect side is wrong in the following ways. It will only pick up the first token information after the Tag name - tokens are array subscripts [<n>] and the optional Read/Write specifier .Read or .Write. Also, internally on the CtAPI side the length is appended to the Tag syntax in the fashion TAG,<dwLength> to become another token. So the length will only be recognised if there are no other tokens, that is, if only the Tag name is passed to CtTagToPoint. The problems are summarised below.

TAG - Tag Only - OK

TAG.Read - .Read and .Write read OK but dwLength will be ignored

TAG[<n>] - [<n>] read OK but dwLength will be ignored

TAG[<n>].Read - Array subscript read OK but .Read (or .Write) will be ignored. dwLenth will also be ignored.

In summary, the TAG is always parsed OK but other attributes may not be depending on what combinations are used.

CIT has confirmed this to be a problem in Citect for Windows versions 5.00. This problem has been fixed in version 5.00 Service Pack D. The problem is on the Citect side of CtAPI so any programs using CtAPI do not need to be recompiled.