Configure an OPC group object

Add a group object to your OPC data source hierarchy

1. Select the new data source object, right-click it, and then select Add OPCGroup Connection on the shortcut menu.

   A new object is created in the hierarchy tree and is named New_OPCGroup_000 by default. Rename it, if desired. You are allowed to add up to 100 new group objects.

   Note: Each group or topic must be uniquely named for the data source associated with it.

   The New_OPCGroup_000 Parameters configuration view (right pane) is displayed.

2. Configure the new group object according to the following option definitions:

   1. Device Group Name: Name of the topic that DDE or SuiteLink clients of Gateway Communication Driver connect to in order to access items at the OPC group. Default value is the concatenation of the OPC data source object’s name and the group object’s name (this cannot be edited).

   2. Update Rate: Value (in ms) used by Gateway Communication Driver to update the OPC group. Minimum/maximum range is 0 to 2147483646 ms. If the OPC server supports it, zero (0) update rate means the data source sends data changes immediately. If the server does not support zero update rate, it typically returns a message including information about its fastest possible update rate. Default value is 1000 ms.

      The update rate can also be adjusted at run time by setting the $SYS$OPCUpdateInterval system item.

   3. OPC Item ID Prefix: String prefixed to all item names added to the OPC group. Default value is blank. The syntax to use the prefix is <Prefix>.<Item>. For example: If the item prefix is boiler1 and the Item name is temperature, the item requested from data source is boiler1.temperature

   4. Use Group Name as Access Path: Provides control over the OPC Access Path for items added to the OPC group. When checked, the name of the OPC group object is used as the OPC Access Path for all items. When unchecked, the default (blank) OPC Access Path is used. Default value is unchecked.

   5. Read Only: Check this box to make all items connected through the OPC group read only. This qualification is in addition to any read-only condition that the OPC server imposes. Unchecking this box only removes Gateway Communication Driver -imposed read-only qualifications. In other words, items inherently read-only in the data source remain so. Default value is checked.

   6. Demand Read After Poke: Provides an option to read an item immediately after a write transaction on the item. When checked, a read transaction is performed on the item whenever it has a write transaction irrespective of the subscription group interval. When unchecked, the value of the item is updated at the specified subscription interval after a write operation on the item. Default value is unchecked.

   7. Browse OPC Items: Opens the OPC browser, in which you can select items directly from the OPC server.

3. Configure the Device Items by one of the following methods:

   1. Use the OPC Item Browser to browse OPC server items and populate in Device Items tab.

   2. Configure Device Items. Select the Device Items tab and add item names and references. For more information, see Configure device item definitions.

OPC groups are used to model the behavior of OPC servers. You cannot add items directly to an OPC data source, but must add them at the group level.

Browse OPC server items and populate in Device Items tab

4. In the OPCGroup Parameters tab, select Browse OPC Items.

   The OPC Item Browser window appears.

5. In the Branches section, navigate and select the node to browse items. The available items populates in the Available Items section.

6. To add an item to the basket, do one of the following:

   • Select the item, and select the + icon on the top right corner.

   • Select the item, and drag-drop to the Basket section.

   • Select the item and press Enter.

   • Right-click on the item, and select Add to Basket.

7. To delete an item from the basket, do one of the following:

   • Select the item, and select the X icon on the top right corner.

   • Select the item and press Delete.

   • Right-click on the item, and select Remove from Basket.

8. To filter the items, select Filter...

   The Specify Filter Criteria dialog appears. Enter the filter criteria using Item Name, Item Data Type and Item Access Rights.