VT_Array syntax in Application Server

VT_Array items from the SIDirect Communication Driver can fail to return good VTQ data in Object Viewer without the addition of an index to the Item/Point syntax. While the syntax provided in this section is correct, VT_Arrays require a [-1] offset. Without this offset, the VT_Array will not count the 0 byte in the range.

Following is an example of the syntax for a VT_Array item to receive proper validation under a LMX client such as Object Viewer in Application Server:

S7C_S7_001.SG1.attribute(DB111,WORD10,4)[-1]

In this example, the syntax has the following structure:

<SIDirect_DiDevice_Instance>.<ScanGroup>.attribute(D<B>d,WORDn,v)[-1]

where

• d is the data block number,

• n is the start address of a 2-byte data array, and

• v is the length of data in elements (the size of the array). Each item in an array is called an element.