Automate Your Functional Test
The automation trend is pushing more functional tests(FCT) systems into automated inline platforms. We are seeing increasing requests of automated inline functional test solutions. Functional test solutions consist of specific test requirements. Every solution uses a combination of instruments and test loads.
It is not difficult to create an automated inline handler for a specific functional test setup. However, these kind of handler systems are unique and non-generic. This is good for small installations with a few systems supported locally. Multiple systems installed across different geographical regions creates challenges for technical support expertise and spare parts availability. To design a generic test platform that will cater to the needs of the wider market is not easy. It needs to allow the integration of different instruments and test interfaces while keeping the rest of the system as generic as possible.
We have the FlexiCore Automated Inline Parallel In-circuit Test(ICT) system that house a standard instrument rack at the back of the system to provide the flexibility for installing different types of instruments according to user’s functional test needs. And because of the simplicity of the system, it is easy to adapt to different customization like swapping the In-circuit card cage for a front instrument rack or changing the test interface plate to allow high current connectors used in functional load testing. Since the launch of the FlexiCore, we have delivered a vast diversity of solutions that ranges from parallel ICT+FCT testing to high-speed flash programming for radar and other automotive boards.
FlexiCore systems used for ICT testing runs on the native In-Circuit Parallel Test (ICPT) software. Those used for FCT testing and flash programming depends on different test executive’s software preferred by the users. Therefore, today, I’m sharing insights on how we can handle the barcode scanning process on the FlexiCore using your very own testplan.
Dual zone reader setup
Every test cycle usually begins with the capture of the serial number barcode of the device under test(DUT). A typical setup you may see is that the barcode reader is position a staging zone before the tester. In this setup, there is an additional process for the tester to attempt to capture the barcode before letting the DUT flow in. The staging zone can be a separate conveyor setup before the tester, or it can also be part of the tester itself. This creates an area where the DUT is stationary and allows for the barcode capturing process, before releasing it into the test area. This method works well and reliable, but it incurs cycle time as the DUT needs to wait for a few seconds before it gets into the test area itself.
Single zone reader setup
The other common setup is to position the reader at the DUT stopper area and allow the DUT to flow directly into the tester. The stopper holds the DUT in place and scanning can take place. After the barcode is capture, the tester then lowers the DUT onto the test fixture and commence testing. Like the dual zone method, holding the DUT and waiting for the scan to take place incurs cycle time.
Single zone On-the-fly reader setup
FlexiCore scans the barcode on the fly to reduce the time needed for the capture. This easily saves 1 to 2 seconds off the overall cycle time and translates directly to higher throughput.
To do this, place the barcode reader at the entrance of the tester. Before each transfer of DUT into the tester, software triggers and arms the reader. When the DUT transfer starts, the DUT enters the tester and passes under the reader. Reader captures the barcode and sends it to the test software. The DUT reaches the stopper position and tester engages the DUT for testing.
Do you see a problem in this setup? Yes, there are some.
In this setup, the DUT is on the move when the reader attempts to capture the barcode. Most readers will not be fast enough to make the capture. Only some expensive higher-end readers will be able to do that. This drives up operation cost. The next issue is that even if the barcode captures successfully, most testplan will need to validate that barcode against their production manufacturing server before allowing the DUT to be engaged onto the test fixture. But there may not be sufficient time to do this as it only takes a few seconds between the DUT entering the system to being engaged onto the test fixture. Trying to capture the barcode and complete the validation within a few seconds may not be possible.
The solution to this is a two-speed conveyor transfer algorithm in the FlexiCore.
To allow for successful capture and the validation of barcodes, the FlexiCore transports the DUT in two stages. When the DUT transfer begins, the conveyor moves at a much slower speed as compared to the normal transfer speed. This allows time for the reader to capture the barcode and the testplan to make the validation. Once the testplan validated the barcode, it sends a Barcode OK command to the FlexiCore and the conveyor reverts to the normal transfer speed to complete the operation. By doing so, the FlexiCore made use of the time taken in capture and validation of the barcode to continue the transfer of the DUT and thus saving precious cycle time.
In the next post, I’ll go deeper into the details of the scanning process and the related commands. So, stay tuned !
Until then, stay healthy and stay safe!
Ping me up with your questions or comments !
kwan-wee_lee@keysight.com\