IDEC WindSRV - Manual (Page 119)

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an array of data values, the text string written should have this delimiter format.
When poking to an array tag in either format, the entire array does not need to be written, but the starting location is
fixed. If attempting to poke data in an array format to a tag that was not declared as an array, only the first value in
the array will be written. If attempting to poke more data than the tag's array size, only as much data as the tag's
array size will be written. If attempting to poke data while leaving some data values blank, the server will use the last
known value for that array element when writing back to the device. If the value in that register has been changed but
has not been updated in the server, it will be overwritten with the old value. For this reason, it is best to be cautious
when writing data to arrays.
In an OPC Client
In OPC Clients that support arrays, the OPC Item data value is actually a variant array data type. The OPC Client parses
the array element data: some clients will create sub tags for display purposes. For example, if the OPC client created a
tag in its database named 'Process,' and the associated OPC item was a single dimensional array of 5 elements, it might
create 5 tags named 'Process_1', 'Process2' and etc. Other clients (such as the OPC Quick Client) may display the data
as CSV (Comma Separated Values).
How To... Create and Use an Alias
Example of a Complex Tag Reference
The following image shows how a Complex Tag Reference appears in the server.
In this example, if a DDE link to an application were needed for the tag ToolDepth, the DDE link would need to be
entered as follows:
= <DDE service name>|_ddedata!Channel1.Device1.Machine1.Cell2.ToolDepth
Although the DDE link's simple Application|Topic|ItemName format still exists, the content becomes more complex
when optional tag groups and the channel name are required as part of the topic. The Alias Map allows a shorter
version of the reference to be used in DDE client applications.
Creating Aliases for Complex Address Paths
For instructions on how to simplify a Complex Tag's address paths by creating aliases, follow the instructions below.
1. In the server, click Edit | Alias Map.