Because there is a limit to how much live data you can get in DBDOC, a user who consumes a large amount of live data resources can greatly reduce the amount of live data available to everyone else. Everyone should use as much live data as they need in order to make the best use of DBDOC when they are analyzing their system, but we recommend the following best practices to ensure that users do not use too much live data when they do not need it.
Check your communication and usage statistics to see how much live data has been requested from your system, and to check if there might be any one or two users who are using far more live data than everyone else. If so, it can be helpful to review how these users are using DBDOC and see if they are following these best practices.
- Ensure that you are not getting data for a block that is offline or that doesn't exist in your system.
- For example, if you are using an out of date .dbdoc file and you try to get data for a sheet that shows an old block that has since been deleted from your system, that will greatly slow down live data for all of your users and greatly reduce the amount of live data that DBDOC can produce. This is because the request for data will stay on the loop until it times out, after about five seconds, so for those five seconds live data might hang for everyone. If this sort of thing happens repeatedly (for example, if a user is trying to look at an entire sheet of old blocks that no longer exist in your system), it could cause live data to become entirely unavailable.
- Use the camera to get Hyperview live data instead of the clock.
- Using the clock button to get live data uses up roughly 10 times more live data than using the camera so we recommend that all users should use the camera for most work -- you should only turn on the clock if you really need it, and you should be diligent about making sure that you turn it off when you are done with the work that required it. Otherwise, you could be using up as much data as 10 more responsible users.
- Close or minimize the Hyperview window when you are finished using it.
- If Hyperview is left running on a computer after you are finished with it, it can continue asking for data. Closing Hyperview when you are done with it, or even just minimizing it, can help a lot to make sure that Hyperview isn't getting a lot of data that users don't actually need. (Hyperview will not get on-document data while it is minimized, but it will still get data for the watch window.)
- Pause data collection in watch window groups when you are finished with them.
- The watch window is mainly intended to be used as a short-term analysis tool -- for most watch window work, we expect that you will trend data for a few minutes and then analyze what that data is doing and then turn off the trending in the watch window. (To turn off data collection: on the **Group** menu in the watch window you can click **Pause All Blocks** to stop getting data for that watch window group; or as a quicker shortcut you can click the clock icon so that it turns white.) If you leave a lot of watch window groups running, that can consume a lot of live data. You can use the watch window to trend blocks for a longer period of time, but the most important thing is to make sure that you turn it off when you are finished getting the data you need -- otherwise, it will keep getting data when Hyperview is open, even if the watch window itself isn't being shown. If you need to keep track of what a block is doing over a very long period of time, or if you want to constantly monitor something all the time, that is the sort of situation where it is better to use a dedicated historian tool instead of the watch window.
- Be careful when opening multiple Hyperview windows at once.
- If you keep opening new Hyperview windows without closing old ones, each Hyperview window could keep getting data -- once you have a lot of them open, it is easy for Hyperview to be requesting a lot of data at once.
- Turn off Show Live Specs when you are done looking at live specs.
- If you are using Show Live Specs and you turn on Live Specs for a lot of blocks, it can take more data to display the live specs because the live specs don't benefit from OPC90's turbo mode. We recommend that when you are done looking at live specs, it is best to turn off Show Live Specs to make sure that you are not getting additional live specs when you don't need them.