OPC Client Data Source

An OPC client provides direct access to data served by OPC Data Access (DA) servers without relying on GE Historian as a bridge between an OPC server and Workflow.

Note: Supported OPC DA specifications are: v2.0x and 3.0.
Tip: You can add up to 3000 groups to each OPC server and 5000 items per group.

OPC items added to Workflow can be used as data items for workflows, events, and equipment properties. Workflow can read from and write to these data items. OPC servers configurations can be imported and exported to other systems.

Important:
  • Workflow supports local OPC servers only; it does not support remote OPC servers.
  • The OPC client supports synchronous reads and writes only; it does not support asynchronous reads or writes.

Edit Description

You can change the description of this resource.
Attribute Value Description
Description User-defined up to 255 characters Provides more information about a resource that a user may find helpful.

The following table describes the OPC Server attributes on the Data Source Editor:

AttributeValueDescription
OPC Server NameUser-defined alphanumeric string (A–Z, a–z, 0–9) up to 255 charactersDisplays the name of the OPC server.
DescriptionUser-defined alphanumeric string (A–Z, a–z, 0–9) up to 255 charactersProvides more information that a user may find helpful.
Server Prog IDUser-definedSpecifies the ProgID of the OPC server you want to connect to. You can select from the list or enter the ProgID. Refer to your OPC server documentation to determine the ProgID.
Health Monitor FrequencyUser-defined numeric valueSpecifies how often the OPC server communicates its health status to the OPC Client.
Note:
  • If you are using OPC DA v2.0x, the client communicates with the server at this interval to monitor the health status.
  • If you are using OPC DA v3.0, the server communicates with the client at this interval to monitor the health status.
OPC Server StatusN/ADisplays the status of the OPC server. Status information includes:
  • Connection Status: connected or not connected
  • State: running or not running
  • Status Info: running normally or not
  • Vendor Info: The name and web site of the OPC Server vendor company
  • Product Version: the version number of the OPC Server
  • Start Local Time: the date and local time the server was started
  • Current Local Time: the date and local time the server status was refreshed
  • Last Update Local Time: the date and local time the server was last updated
Note: The OPC server status information is not automatically refreshed; you must refresh the status manually.
RefreshN/AClick to refresh the server status information.

Add OPC Items to Workflow

Before you can add OPC items to Workflow, you must add one or more groups to the OPC server. You can choose to detect changes in an OPC item value by enabling the associated groups, or by reading the OPC data item. If a group is not enabled, no event notifications about data changes are sent to subscribers of the associated items.

You can also choose to configure a group to read OPC items from the OPC server's cache, or to get values directly from the device the server is reading from.

After you add your OPC groupss, you can browse the OPC server and add up to 5000 items to each group. The items are automatically added to Workflow when you add them to a group. If you want to add only a subset of the available items, you can expand the top level item list in the Server Items area and then select the check box beside each item or set of items you want to add. You can also remove items from the Selected Items list

The following table describes the OPC Server Group attributes on the Data Source Editor.

AttributeValueDescription
OPC Group NameUser-defined alphanumeric string (A–Z, a–z, 0–9) up to 255 charactersDisplays the name of the OPC Group.
DescriptionUser-defined alphanumeric string (A–Z, a–z, 0–9) up to 255 charactersProvides more information that a user may find helpful.
Update RateUser-definedSpecifies the rate, in milliseconds, at which the server is requested to update items in this group. Event notifications are sent to subscribers of items associated with the selected group when data changes. The default rate is 1000 ms.
EnabledUser-definedSelect this check box to allow event notifications to be sent to subscribers of items associated with the group. Event notifications are sent when data changes and at the rate specified in the Update Rate field. Groups are enabled by default.
Read ModeSystem-definedSelect the method to use for reading OPC item values.
  • Cached - OPC item values are read from the OPC server's cache.
  • Device - the OPC server bypasses its cache and reads the OPC item values directly from the device the server is communicating with.
Browse ServerN/AClick to browse the selected server for items.
Server ItemsN/ADisplays the items contained by the selected server. Select the highest level check box to select all of the items and add them to the Selected Items list. This check box is not available if the server contains more than 5000 items.
Selected ItemsN/ADisplays the items you selected to add to Workflow.
RemoveN/AClick to remove the selected item from Workflow. Removing an item from Workflow does not remove it from the server.