Hi,

“Simple Samples” are small projects that demonstrate simple features. The target is giving a quick overview about the theme and be used as start point for related discussions. Follow there are a short description and the configuration main steps.

Trends are an important tool for process signals evaluation. E.g. Trends are related to time, but there is situation where the trends should display the relationship between two variables. This Simple Sample brings two ways to insert data / plot values that are not collected in the cyclic real time bases. One is based on a trigger bit, that means that the data is collected in real time but not cyclically. The other one by input data in the log archive with an external (auxiliar variable) time reference. This feature enable, for example, to plot (even indirectly) graphics that represents the relationship between two variable at a non-time basis relevance or that not be collected by normal HMI scan process.

TIP: This application example is an extension of the use of function trends. An example of how to configure Function Trend objects is showed in the post  "WinCC Unified – Simple Sample - Function Trend (Trend X, Y)" (https://support.industry.siemens.com/tf//br/en/posts/wincc-unified-simple-sample-function-trend-trend-x-y/226266/?page=0&pageSize=10).

Configuration main steps:

• Open a pre-configured project with a functional trend object.
• Create a Log: Project tree, Logs, Data logs tab, Add new.
• Create an auxiliar TAG (DateTime) as data base (here named as "DateTime").
• Create an auxiliar TAG (Boolean) as trigger (here named as "Trigger").
• HMI tag's definition: select the logged tag (here named as "HMI_Tag_1" and "HMI_Tag_2"), select "Logging tags" tab (between tag table and inspector window), change the follow properties:
• Logging mode = On demand
• Trigger mode = any option else "none" (that means Rising edge, Falling edge, Rising and falling edge, here "Rising and falling edge")
• Trigger tag = trigger signal (here "Trigger" tag)

• To insert data on the log:
• Drag & Drop the HMI_Tag_1 and HMI_Tag_2 from the tag table to the screen to give a new value to it.
• Drag & Drop the DateTime tag from the tag table to the screen to give a new value to it.

Variant 1 - trigger triggered data insertion:

• Insert a button and configure it to invert the bit of the Trigger tag

Variant 2 - data insertion based on an auxiliar variable to represent the time stamp.

• Place a button on the screen, use the system function WriteManualValue twice. Parameters:

First call:

• Logging tag name = data log name (in our example, HMI_Tag1:LoggingTag_1)
• Value = HMI_Tag_1 tag
• Timestamp = DateTime tag

Second call:

• Logging tag name = data log name (in our example, HMI_Tag2:LoggingTag_2)
• Value = HMI_Tag_2 tag
• Timestamp = DateTime tag

Note: in the simple sample project, as demo propose. HMI_Tag_1 and HMI_Tag_2 are also incremented every 5 seconds so to descript a circle in X x Y analyses. A second button was added to give to DateTime tag an actual value.

Simple sample program (zipped / archived).