Supported OPC Client Types
The following types are supported by this communications interface:
Analog
3D_BCD | Positive BCD values ranging from 0 to 999. |
4D_BCD | Positive BCD values ranging from 0 to 9999. |
DINT | Integers ranging from -2,147,483,648 to + 2,147,483,647. |
INT | Integers ranging from -32,768 to +32,767. |
REAL | Floating-point numbers. |
SINT | Integers ranging from -128 to +127 |
UDINT | Unsigned integers ranging from 0 to 4,294,967,295. |
UINT | Unsigned integers ranging from 0 to 65,535. |
USINT | Unsigned integers ranging from 0 to 255. |
Boolean
BOOL | A one digit Boolean point with a value of 0 or 1. |
BYTE | An 8-bit array of Boolean points. |
WORD | A 16-bit array of Boolean points. |
DWORD | A 32-bit array of Boolean points. |
Text
STRING A one | Character alphanumeric. |
STRING_20 A 20 | Character alphanumeric string. |
STRING_8 An 8 | Character alphanumeric string. |
STRING_80 An 80 | Character alphanumeric string. |
The OPC Client supports all CIMPLICITY data types. The target OPC Server must also support the same data types. Since some servers implement strict type checking, it is recommended that you check the OPC Server documentation for data types supported by any OPC Server.
Points may be single elements or array points if the OPC Server supports that configuration.
- Review Data Access 3 specification documentation to determine if Data Access 3 provides for passing arrays of data. Data Access 2.0 specification does not provide for passing arrays of data. It does not define how an OPC Server should pass array data to an OPC Client.
- Some OPC Servers provide a way of defining Visual Basic (VB) style arrays (usually by appending an element count onto the Item ID). How arrays are supported, if they are supported, is specific to the OPC server. Consult your OPC Server vendor for details.
If an OPC Server does support VB style arrays, they can be configured in the CIMPLICITY OPC Client by simply setting the number of elements under Point Properties to match the number of elements defined in the Item ID (the CIMPLICITY point address).
Note that these values must match.
Example
If the array is defined by the syntax MyItem_20, indicating a twenty-element array, then the Elements property of the Point Properties in CIMPLICITY must also be set to 20 or the array will not be successfully retrieved from the OPC Server.
OLE passes the array within a single Variant value. Therefore, it is not possible to read or write a single element. The entire array must be passed when reading from the OPC Server or writing to the OPC Server.