I found a VB6 example among your examples which illustrated the use of ItemDescriptor->ItemId to get this information. Thanks.

In the Download section of your website, when you click PHP, there is an example that shows how to use PHP with the ItemChanged event. The example shows how to read the Vtq of the changed item. Looking through your documentation the Vtq class provides properties such as Value, Timestamp and Quality but I don't see how to determine the item (OPC tag) that actually tripped the event.

In the case of the PHP example provided, only item (OPC tag) is subscribed to so the item is implied but if the example is expended to include multiple subscribed tags, one would need to know which item (OPC tag) caused the event trip.

The ItemChanged event (at least in the example) provides a $varSender parameter (which might be the item that tripped the event) but I have not been able to successfully display its contents or identify its class type so that I can use the documentation to determine what properties it has.

Or is this not possible and one needs to register a separate event for each subscribed item?