Switch manager takes care of your test connections
Switch matrixes allows you to connect instruments to different test points on the board for measurements. A typical functional test setup uses basic instruments like digital multimeters (DMM), frequency counters and test-loads as well. Switching these instruments for a single board (DUT) can easily generate over ten connections or more. Similarly, if we increase the number of DUT, the number of connections multiplies. Panelized board design is gaining adoption as it maximizes the throughput in production. With the increase in number of boards (DUT) in each panel, the requirement to switch the instruments around becomes significant.
How are you managing your switch matrix connections? Do you use a spreadsheet table that lists the connection paths and then manually enter each one of them into your testplan?
It is tedious to create and maintain the accuracy of the switch paths in the testplan manually. A simple mistake in the connection path entry may cost you hours of debugging effort or worse, a damaged hardware or DUT.
Using PathWave Test Executive for Manufacturing(PTEM), you create and manage connection paths graphically. You establish the connections by dragging the signals from the instrument/DUT to the switch matrix channels. Switch manager presents a graphical view of your test setup so that one look at it, you will be able to see all the connections between instruments, switch matrix, and the DUT.
Creating a block diagram
Using Switch manager, you can create a block diagram of the entire test setup. This helps with troubleshooting efforts when you need to check the connections of various signals to see what goes where. Each instrument library in PTEM has its own graphical representation. For the DUT, you just need to define the number of connection points and their name prefixes.
Switch manager shows you the selected instruments and DUT graphically. All you need to do is to drag the ones you need into the connection area and then connect their ports together by dragging them to each other. In the example, I linked the “Hi” port of then M9182 to “Inst1” of the pin matrix.
Once you complete the connections, what you get is a block diagram of your test setup. This is the base of your switch path creation. You can also use this as a reference when troubleshooting the testplan.
Creating switch paths
Switch manager creates connections needed for your tests. A connection contains multiple via points which connects the ports of the pin matrix to its internal signal buses (ABus1 to ABus4). Through the ABuses, the pin matrix establishes the connection between instrument and DUT.
Typically, you want to group the via points based on the tests they are supporting. You can create multiple via points in a single connection and the switch test step can switch all of them at the same time. This reduces the overall test cycle time as compared to switching each one sequentially. Alternatively, you can also create separate connections and execute them separately in different test steps.
Switching test steps
The switch test step allows you to include multiple connections from the switch manager. Select the “Execute per channel list” option to enable multiple connections switch simultaneously. You should be able to do this for most connections except those that are more sensitive to the sequence of connections.
You can create child steps under the switch steps, which the testplan executes when the switch fails. With this, you can create messages or logs to help with troubleshooting and reporting.
At this point, the testplan had its switching test steps completed, and you can always edit the steps to change the connections if required.
So, comparing to manually editing the testplan to create each switching commands, the graphical Switch manager is an easier method to create and manage the switching of connections. Test development is now faster and more effective with you spending your precious time working on real test setup instead of manual data entry work.
Until the next post, stay healthy and safe!
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