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th1nker

One OPC server logging to two databases?

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Hi guys, I was wondering if it is possible to have a single OPC server that logs data to two separate databases? I currently have Kepware communicating with a couple dozen PLCs and logging the data to MYSQL. I'm trying to find a way to log data to two separate databases so that one can be used to simulate and test changes. Originally, we had two instances of Kepware, each running from a unique computer, trying to communicate to each PLC, but the OMRON machines using the FINS Ethernet driver didn't like that and kept getting the "not responding" error on one of the instances of Kepware. With this in mind, I'm trying to find out what the best way to log data from each PLC to two separate databases. Any ideas? Thanks in advance for the help.

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Hello, I wish I had an answer for you regarding Kepware. If you are unable find a solution, PeakHMI can log to an unlimited number of databases.

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Thanks for the response! Unfortunately, I'm a coop student at a corporation and they already have standards up. It would be next to impossible for someone in my position to recommend PeakHMI to my superiors.

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The OPC server should be able to support more than one client. Does your application use the server client arrangement? I have had OPC servers sending data to an HMI and a historian on two different boxes many times. I don't know off hand how many clients the kepware can handle at once. Plus the about of data and the polling time will influence the number of clients also.

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Hello, Right, an OPC server should be able to support many clients and in the instances you sighted the HMI and Historian are OPC clients. In the OP case, he is trying to log data to a MySQL database. It is not an OPC client. The logging is a function of the program outside of OPC.

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The problem lies in Kepware's data logger for me. It only allows me to list a single table in SQL to log to. In order to log to another one, or even another database, we had to get an OPC DA driver which basically uses one OPC server to communicate to the PLCs and write to SQL, and another OPC DA server to monitor the tags from the first one, and log data to a second SQL server. We're still trying to get it working. We've tried numerous solutions, and each one has caused some kind of problems. For instance, when we had multiple instances of Kepware running with clone channels and devices, it caused communication issues on the main Kepware server pretty much as soon as we started runtime. OPC DA looks like the only way we can log to more than one mySQL server using Kepware without messing up any connections. I'll report back if/when we get OPC DA to properly work, just in case anybody has a similar issue in the future.

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Have you contacted Kepware's support team about your issues? You had mentioned data logging within the server. Are you using the data logging plug in? What drivers did you purchase?

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