Production test

[Joerg]

Hi,

we are using a nRF51822 built into an industrial sensor device. As part of the final production test we want to check the RF connection between the BLE chip and a test system. To keep the production test system as simple as possible we decided just to check if the BLE chip sends advertising telegrams after power up and not to establish a bidirectional BLE connection.

Is in your opinion such a test-strategy sufficient for production-testing of the BLE hardware (nRF-chip, balun, antenna)?

regards Joerg

[run_ar]

That might be ok, however I would recommend reading our application note on how to set up production testing using dtm, this is available here.

[Gustavo - Argenox]

Joerg,

The answer to this question is always a tradeoff. Your test will tell you whether the functionality of the system works. But there can be issues that are more subtle where a component isn't placed properly and affect the transmit power and sensitivity.

The problem is that real testing of the device requires a conducted test in which the tester is connected to the system. Few devices have this connector due to extra expense. This works well for smartphones that are expensive, less for small sensors that cost less than $10.

A tradeoff between these is to use a Golden unit device and place your devices under test at a certain location and distance that is consistent. Then, measure the RSSI of the packets sent by your product to ensure it is in a certain range. You will then be able to notice any gross deviation. The Nordic App note recommends a shielded box and the standard attenuators for this which will help make the test better.

Aside from this, visual inspection or AOI and even random sample tests can help find if there is anything wrong.