How to subscribe to OPC data changes in PowerShell
From OPC Labs Knowledge Base
The following PowerShell code subscribes to an OPC item and displays the incoming data changes:
Add-Type -Path OpcLabs.EasyOpcClassic.dll
# Create EasyOPC-DA component
$client = New-Object OpcLabs.EasyOpc.DataAccess.EasyDAClient
# Hook events
Register-ObjectEvent -InputObject $client -EventName ItemChanged -Action { Write-Host $EventArgs }
# Subscribe
$client.SubscribeItem("", "OPCLabs.KitServer.2", "Demo.Single", 1000)
We have tested this with QuickOPC 5.40 and PowerShell 3.0.
Note: For some issues and limitations, see How to read an OPC item value in PowerShell.
Links related to/used when writing this article:
- https://blogs.technet.microsoft.com/heyscriptingguy/2011/06/16/use-asynchronous-event-handling-in-powershell/
- http://www.get-blog.com/?p=189
- http://serverfault.com/questions/270568/need-to-add-a-wait-command-to-a-powershell-script
- http://stackoverflow.com/questions/1478545/handling-events-with-powershell
