I am running a PI OPCDA interface ver. 18.104.22.168 + new PI Buffer Subsystem ver. 4.3. The OPCDA server comes from WonderWare's product called "GSGateway". I only used the "Advise Tags" mode to configure around 24k tags with 4 instances on the same interface node. Also, I configured 200 PI advise tags per group as suggested by OSIsoft tech support. The data flow looks good. But I got so many tag events having errors like "Scan Timeout". I tried to adjust the Update Rate (which is default as Scan Class#1 rate) from 3 secs to 15 secs. It looks like the count of such "Scan Timeout" data has been reduced quite a bit. But it still shows a large amount of such errors. I wanted to do some FINE-TUNE to solve / minimize this issue. So, I have very important question to ask OSIsoft OPCDA interface specialists: Is there any guidelines to help me out solve this issue? Your quick response is highly appreciated.