How to calculate the average of multiple runs in BK Connect?

One of the most common calculations done in traditional data processing is the average of multiple runs, for both steady-state and non-stationary measurements. The challenge with Run Averaging is defining which runs to average together. This is where our new Record and Process task comes in, providing an easy overview all recordings and results based on run number and measurement number in one table.

A run is an individual measurement and is incremented automatically, whereas a measurement includes all the runs that have the same Test Condition and Device Under Test. The Test Condition and Device Under Test are user-defined metadata fields that can be found in the project tree. To take full advantage of this new workflow concept, you need to use these metadata attributes.

 

There are three paths to how you can start your tests for a day:  

1. Predefined test plan with specific Device(s) under test to be tested in known Test conditions
2. Ad-hoc workflow where you are not sure what you will test or how it will be tested
3. A combination of the above, either because you know where you will start, but you may learn along the way and need to modify the test plan.  

 

The new Record and Process task can handle all these scenarios.   

We can begin by defining the Device(s) under test and the Test conditions. These can be created in the project browser or imported from a file.    

In the Record subtask, you can select the test condition that will be performed next. If you are unsure of the test condition or an unplanned test is decided to be performed, you can deactivate the Test Conditions. In this case, the measurement number is automatically incremented for each new recording.   

 

Once you have selected the Device under test and Test conditions, you can make recordings. BK Connect automatically generates the name of the recording based on the user-defined attributes. This functionality can be enabled through the task menu. In this example, we have used the Setup name, Device under test name, and active test condition to define the name of the recording. As these values are updated, the name of the recording is automatically updated, saving time when it is critical and reducing the likelihood of mistakes. The same option is available for defining and automatically updating the directory path for the recording.  

When in the recording mode, you can select any recording and signal to view the time history for validation. If multiple recordings or channels are selected, then the displays are populated based on internal rules. When making measurements, the table is as compact as possible, so any common metadata for all runs is placed at the top of the table. As soon as the metadata value is no longer unique, it will move and become an additional column to the left of the table.   

Record Sub Task

 

As errors do occur during the measurement, for example if the user forgot to update the Test condition or Device under test before starting a run, correcting the documentation is critical for these common occurrences. BK Connect allows you to move a run to a different measurement to update the metadata for this specific run.

 

In addition, you can also update the Test condition or Device under test for all runs in each measurement, giving you a high degree of flexibility in adjusting your test as they go. These changes are modified in the data in the project and the files on the disk. Any changes that need to be made to reorganize the measurements and runs must be made before the processing has been started. If processing has been completed and editing needs to occur, you must manually delete the processed data from the project browser.

Once you are satisfied with the recording(s), you can navigate to the Process sub task and start the analysis. By default, the processing will begin in the active setup, but this task allows you to define which setup the recordings should come from and which processing setup to use. The average is automatically calculated for each measurement and is stored to the project browser with the naming convention name Avg (runs included in the average), for example, FFT Setup, Baseline, Low Engine Speed, High-1 Avg(1,2), and the action category is Re and Process – RunAvg. Hence, it is easy to find on the Team Server. If the averaged results are not necessary, this calculation can be disabled through the task menu.

Process Sub Task

 

With the thumbs-up icon, you can decide which runs should be included in the average. The average is automatically recalculated when a change is made and replaces the currently stored results in the project browser. To select a different setup (process chain configuration), use the processing selector at the top of the test plan table.  

Any row or rows in the Test Plan table can be selected to populate the display. The signal selector grid next to the table can be organized to group data based on signal name, Physical Quantity, Component ID, Node Id, or Direction. Once a signal is selected, it is overlaid based on physical quantity and function type in the display. Intelligent legends reduce the complexity of more complex features for high usability. 

 

Another aspect of the rules that can be challenging is defining the axis limits. In the fast displays you can manually enter the value on the max and min values on the y-axis. This information is persisted for all displays with the same physical quantity and function type, until the y-axis is reset to auto scale mode, by double clicking on the axis. 

This functionality works in the same way for the displays created in the Monitor.  

After you have completed all the recording and processing for a given test, you can send the data to the Team Server directly from the Record and Process task. The recording, processed and averaged results all have a unique action category making it easier to search and view the data in the Team Server.

Advanced Query for all data from the Record and Process task

'Action category’ IN [‘Rec and Process – Recording’,’Rec and Process – Processed’, ‘Rec and Process – RunAvg’]

To continue the journey with the data, once it has been stored to the Team Server, (local or network), and the appropriate query executed, BK Connect enables multi select in the team search. This way you can view the data before you decide what to import and start making decisions.

In addition, self-contained BKC files are created when recordings and results are exported, including information such as Test, Setup, Test conditions and process chains. When imported into a new project, the entire project browser can be recreated, allowing for proper traceability for where and how the recordings were made or the data processed. The imported data can come from the Team Server or from an external file. This information is not included in the original recording so the data must be exported to a file or Team Server. With the process chain included in the exported results, you now have complete traceability as to how the results were processed. 

Multi Select in the Team Server

 

Traceability is very important. In other processing tasks it is possible to process data, change the process chain and then process the time data again. So, within a single setup you could have results from multiple process chains and no way to deconstruct how the data was reproduced. Once data has been processed in a setup, you cannot reprocess the time data. To reprocess data in the active setup, you first need to delete the results in the processed data folder or create a new setup. This is by design to improve the traceability of the results.

The new Record and Process task improves traceability for both the recordings and results. This workflow gives an overview not only to those acquiring the data, but also to test managers and test requestors. It is easy for all to see what has been completed and what is left to do before your day of testing is complete. Once the workday is done and the data is shared with the Team Server, it is now available for others in your organization to continue the product development process.  

 

Learn more about data processing in BK Connect:

> BK Connect Type 8403: Data Processing Software