Datalogging for functional test using PathWave Test Executive for Manufacturing
Data is the foundation for logical decision-making. Along a typical print circuit board assembly (PCBA) line, production servers collect data from test stations and assembly machines. This information allows us to track the performance of the production line and triggers the necessary corrective actions if the need arises. Industries like Healthcare, Aerospace and Automotive archive production data for traceability. When a product malfunctions in the field, investigators retrieve these records to analyze the root cause of the failure.
Collecting test data at the in-circuit test (ICT) and functional test (FCT) stages are important. The recorded information shows the condition of the product and environment at the time of its assembly. In case of a catastrophic product failure in the field, this may form critical evidence when it comes to judicial proceedings where both monetary and reputation liabilities worth millions of dollars are at stake in terms of claims or massive product recalls.
For ICT, datalogging is already part of the features available in the software. All we need to do is to enable the datalogging and the software to generate the log files accordingly. This is possible because of the organized structure of the ICT test program. Basically, ICT test deals with passive measurements and collects data like measured values, test tolerances, user ID and date-time information. The format of the content is simple as there are only a few data points to record.
On the other hand, datalogging for functional test is unpredictable because it is the developer who decides what to log. The variety of information logged is also wider compared to ICT. Unlike ICT, which primarily records measured values and tolerances, FCT data logs can include information like calibration tables, chip identifications, firmware versions, and environment temperatures.
PathWave Test Executive for Manufacturing (PTEM) uses a flexible approach to allow you to customize your data log. Instead of a standard “log everything” feature, PTEM lets you choose the necessary information to include in the data log. This reduces the overall file size of the data log as it does not have unnecessary data.
In PTEM, you can selectively log almost every variable available in the software in your testplan. You have the flexibility to customize the content to log, as not all of them are useful information for the data log. The datalogging configuration editor lists both the system and user variables for selection as shown in Figure 1. You simply drag and drop whichever variable that you need to include in your data log into the list on the left.
The top-down order of the selected variables list decides the columnized order of the log file, where the topmost variable translates to column A and subsequent variables will populate the consecutive columns to the right, as shown in Figure 2. When you need to move the columns around, you simply drag the variables in the list to your required order position.
The testplan records all limit-checks test steps in the data log file. You do not have to add the Data Log Report Generation test step for each of the limit-checks. PTEM tracks the progress of the tests and collects the information in real time. Upon completion of all required tests, the Data Log Report Generation test step compiles and saves all information to the data log file.
The folder path and filename of the data log file are customizable as well. Using pre-defined tags enclosed within < > brackets, you can construct the preferred folder and filename for the data log file. You can segregate the data logs from different test plans so that they do not mix in the same folder. PTEM uses comma as separators for different field in the data log file. You can also select a different separator to use so that it produces a data log file that matches the needs of other applications that use its data.
Creating data logs for your test is now simple and fast. All you need is to add the Data Log Report Generation test step into your testplan and then select what goes into the data log. That is all there is to it.
Until the next post, stay healthy and safe!
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