To ensure the highest throughput of point values through the GagePort Mitutoyo OPC Server to an OPC Client, the client should always request the canonical data type of an attribute.
Example
The following table shows data types that should be requested based on the value source with example variant types.
|
Client Requests |
Should request |
Variant Type |
|
GPFP gage hub |
Four-byte REAL |
VT_R4 |
|
MIG2 gage hub |
Four-byte REAL |
VT_R4 |
|
SIMPLE serial device |
Strings |
VT_BSTR |
By requesting a point in canonical form, the OPC Server does not have to coerce (or convert) between the data type stored internally and the data type requested by the OPC client.
The OPC Server provides coercion support for all non-array OPC items. The OPC Server utilizes standard Microsoft coercion support routines. A drawback to relying on coercion is the penalty of extra processing overhead required for each transaction. However, relying on coercion in the OPC Server may simplify the OPC client or provide the user with the ability to select the data type most applicable.
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|
GagePort Mitutoyo OPC Server data types. |
