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For purposes of this example, we'll just use a generic OPC sample client to show you how to connect to the OPC Time Monitor. First we start our OPC client and using it's instructions, tell it to show us a list of available OPC servers. The OPC Time Monitor appears as "OPCLabs.TimeMonitor.2". This is the ProgID of the OPC Time Monitor. We select it and then move to adding items using our OPC client.
When we first enter the OPC Item browse tree for the OPC Time monitor, because we have enabled auto-discovery and browse-through, we see the branch > Discover Machines >. This branch is used to browse through the OPC Time monitor and automatically discover additional OPC servers for ad-hoc item monitoring. Below this you will see the various Time Folders that have been configured - in this case "Channel_1", "Channel_2", and so on. At the top level notice the $Reset tag. This is a global reset tag for the entire OPC Time Monitor. If the user writes a 1 to this tag, all aggregates for all Time Folders and Time Topics will be reset and previous aggregates copied to the "Previous" version tags
Next we will browse into one a Time Folder. In this case we are using a Folder that was not visible in the prior screen. The Time Folder in this case is "Tag Group 1" and the Time Topic is "Channel1.Device1.Global.T4_". Notice that under the Time Topic there are 3 folders - one each for $Stable, $InCondition, and $OutofCondition. We will explore the contents of these next. At the top level, notice the tags at the right. These are what we call condition summary tags. These tags provide the current process value for the selected Time Topic and boolean tags that indicate the current condition of the Time Topic. Also a $Reset tag is provided that will reset the aggregates for only this Time Topic.
Next we will browse into the $InCondition folder to explore the aggregates for this Time Topic. At the top level notice the tags at the right. These tags provide some summary information about the the $InCondition state. (click for details). The items at the right will return data in VT_DATE format. Your OPC client may not support VT_DATE format. If you use one of the items on the right and get Unknown for the value or Bad for the Quality, then your client likely does not support VT_DATE format. At the left there are folders that match the names of each summary item at the right. If you open these folders, each of the time measurements is provided in a variety of other data types, which we will explore later.
Next, Lets look at the "Aggregates" folder. In this folder you will find the aggregate values calculated by the OPC Time Monitor. At the right are the values that are available. The time Values are available in VT_DATE format by default. The CycleCount item is a Long datatype. If you then open the Aggregates folder, you will find that each aggregate value is also exposed in a variety of other time formats.
Below is an example of the condition summary item "PreviousServerTime" with some of the different time formats shown. For more details on the different time formats available visit the condition aggregates page.
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