Issue:
We write data to PLC by gateway script but SCADA sometime can't write data to PLC at same time. Few minutes later, the system back to normal. For the details, please refer to log as below. We also check network status, the network is good. So far, I have no idea for this issue. What’s your take on this? Thanks.
Basic Information:
Version: 8.1.23
OPC-UA Tag: about 9,000 tags
OPC-UA Device: about 100 Device
Occurrence frequency: Randomly
That means the write operation didn't get an acknowledgement from the OPC connection that the write happened. Is the offending tag always the same device? Or scattered among many/several devices? Are the devices using native IA drivers through the built-in OPC Server? Or are the connections via OPC/UA? If a native IA driver, which one?
The issue occur at different device. Our scada connect with AB PLC via OPC/UA(Allen-Bradley MicroLogix, Allen-Bradley Logix Driver). We don't use IA driver. I change the function "writeBolcking()" from to "writeAsync()" but I'm not sure the issue could be resolved or not.
This looks like a contradiction, unless you are using RSLinx Enterprise OPC UA?
You might want IA support to look over your shoulder and/or investigate directly (via support).
Allen-Bradley Logix Driver Setting is as same as other machine, is there something wrong? The issue occurs randomly. The event hasn't happened yet after I added log in gateway script.
That is the IA driver.
Capture the return value from system.tag.writeBlocking()
. That is a list of quality codes for the write for each tagpath/value you provided. Search that returned list for non-good qualities and log the tagpath/value/quality for those.
That will provide the next step in your investigation.
Thank you for the information. I added the log in the gateway script but the issue doesn't occur recently. If same issue occur again, I'll check quality codes first.