OLE for Process Control (OPC) Device Driver allows AggreGate Server to communicate with OPC Servers, i.e. act as OPC Client. Data provided by OPC Servers (and hardware devices "behind" them) is converted into unified form to allow access from different AggreGate facilities. See Devices article for more information about the "normalized" representation of devices in Tibbo AggreGate.
Unlike most OPC Clients which require the OPC Server and OPC Client to reside on the same computer, AggreGate Server communicates with OPC Servers using Distributed COM (DCOM) technology. It allows AggreGate Server to access OPC Servers via IP networks or the Internet.
Another advantage of using DCOM is that AggreGate Server provides access to OPC Servers from operating systems other than Microsoft Windows, including Linux/Unix and Mac OS.
AggreGate Server's OPC Driver supports the OPC Data Access specification. Support for other OPC Standards and Specifications, including OPC Alarm and Events, will be implemented in future versions of AggreGate.
In order to allow AggreGate Server to access your OPC Server, it's necessary to configure DCOM service on the machine running it for remote access. See Configuring DCOM for Remote Access for information on this subject.
OPC Server Discovery
OPC device driver supports OPC server discovery. Discovery is the process of scanning a number of IP network hosts, finding available OPC servers, and creating device accounts for them.
The comprehensive description of OPC server discovery is available in AggreGate SCADA/HMI documentation.
OPC Item Quality
The quality of OPC items is reported as status of corresponding device setting variables. To check the status of a certain setting, open OPC device configuration in the Properties Editor and hold mouse over the setting status icon. Item quality will be shown in the tooltip:
To see the quality of all items at once, open Settings Synchronization Status tab of device status dialog. Item quality is shown in Synchronization Status column:
Driver Information
Driver Plugin ID: |
com.tibbo.linkserver.plugin.device.opc |
Global Settings
None defined.
User Level Settings
None defined.
Device Properties
OPC Server Connection Properties
Connection settings define how AggreGate Server communicates with a certain OPC Server. These settings may be accessed using Edit Device Properties action of Device Context. Here is a list of available connection properties:
Setting |
Description |
Host |
IP address or host name of OPC Server. |
Domain |
Name of OPC Server's Windows Domain (optional). |
User |
Name of Windows User Account used to access the OPC Server using DCOM. |
Password |
Password of Windows User Account. |
Application Class ID (CLSID) |
Class Identifier of the OPC Server. (E.g. F8582CF2-88FB-11D0-B850-00C0F0104305) |
Programmatic Identifier (PROGID) |
Programmatic Identifier of OPC Server. (E.g. Matrikon.OPC.Simulation.1) |
|
It it sufficient to specify either CLSID or PROGID of the OPC Server, not both of them. |
Device Assets
Hierarchical structure of assets provided by the OPC device driver exactly matches tree-like structure of OPC item groups.
Device Settings
OPC device driver creates one Device setting variable for every OPC server item.
Type Conversion
The following table shows how OPC types are converted to AggreGate types:
OPC Type |
AggreGate Type |
VT_BOOL |
Boolean |
VT_BSTR |
String |
VT_NULL |
String |
VT_EMPTY |
String |
VT_INT |
Integer |
VT_I1 |
Integer |
VT_I2 |
Integer |
VT_I4 |
Integer |
VT_UI1 |
Integer |
VT_UI2 |
Integer |
VT_UI4 |
Integer |
VT_DECIMAL |
Integer |
VT_DATE |
Date |
VT_I8 |
Float |
VT_R4 |
Float |
VT_R8 |
Float |
VT_CY |
Float |
Device Operations
No operations provided by the driver.
Device Events
No events provided by the driver.
Connection Handling
This driver makes the device Online if:
| • | TCP connection to an OPC server was successfully established |
| • | DCOM authorization did not fail |
Synchronization Details
OPC Servers are synchronized with AggreGate Server like any other Devices. Synchronization between AggreGate Server and OPC Server includes the following steps:
| • | Reading information about settings provided by OPC Server and creation of Settings Cache. Settings are divided into several groups, according to OPC Server's internal division. |
| • | Reading OPC Server setting values and storing these values in settings cache. |
OPC Server Status
View Device Status action of OPC Server's Device Context provides additional information about OPC Server status:
| • | Bandwidth |
| • | Build Number |
| • | Current Time |
| • | Group Count |
| • | Last Update Time |
| • | Major Version |
| • | Minor Version |
| • | Server State (Available states are: Communication Failure, Failure, Configuration Error, Running, Suspened, Test and Unknown) |
| • | Server State Code |
| • | Start Time |
| • | Vendor Information |