ReadTag (RT Unified) - WinCC Unified

WinCC Unified Open Pipe (RT Unified)

ft:publication_title
WinCC Unified Open Pipe (RT Unified)
Product
WinCC Unified
Version
V20
Publication date
06/2025
Language
en-US
ReadTag

Description

The "ReadTag" command reads multiple tags. The tag value, the quality, the quality code and the time stamp are signaled.

The order of tags in the response corresponds to the order in the "ReadTag" request.

Request

{"Message":"ReadTag","Params":{"Tags":["<Tag>","<Tag>"]},"ClientCookie":"<Cookie>"}

For example:

{"Message":"ReadTag","Params":{"Tags":["Tag_0","Tag_1"]},"ClientCookie":"myRequest1"}

Response

OnSuccess

{"Message":"NotifyReadTag","Params":{"Tags":[{"Name":"<Tag>","Quality":"<Value>","QualityCode":"<Value>","TimeStamp":"<Value>","Value":"<TagValue>","ErrorCode":<Value>,"ErrorDescription":"<ErrorText>"},{"Name":"<Tag>","Quality":"<Value>","QualityCode":"<Value>","TimeStamp":"<Value>","Value":"<TagValue>","ErrorCode":<Value>,"ErrorDescription":"<ErrorText>"}]},"ClientCookie":"<Cookie>"}

For example:

{"Message":"NotifyReadTag","Params":{"Tags":[{"Name":"Tag_0","Quality":"Good","QualityCode":"192","TimeStamp":"2019-01-30T11:25:35Z","Value":"16","ErrorCode":0,"ErrorDescription":""},{"Name":"Tag_1","Quality":"Uncertain","QualityCode":"76","TimeStamp":"2019-01-30T11:25:35Z","Value":"1","ErrorCode":-2147483620,"ErrorDescription":"Tag does not exist"}]},"ClientCookie":"myRequest1"}

OnError

{"Message":"ErrorReadTag","ErrorCode":<Value>,"ErrorDescription":"<Error text>", "ClientCookie":"<Cookie>"}

For example:

{"Message":"ErrorReadTag","ErrorCode":-2147483621,"ErrorDescription":"Failed to Read", "ClientCookie":"myRequest1"}