{"id":16958,"date":"2023-12-18T20:22:35","date_gmt":"2023-12-18T20:22:35","guid":{"rendered":"https:\/\/www.dmcinfo.com\/blog\/16958\/using-algorithms-for-efficient-multiplexing\/"},"modified":"2025-12-23T09:46:53","modified_gmt":"2025-12-23T14:46:53","slug":"using-algorithms-for-efficient-multiplexing","status":"publish","type":"post","link":"https:\/\/www.dmcinfo.com\/blog\/16958\/using-algorithms-for-efficient-multiplexing\/","title":{"rendered":"Using Algorithms for Efficient Multiplexing"},"content":{"rendered":"\n

In Test and Measurement Automation<\/a> projects, we often have to make numerous, quick measurements for test points on a device being tested, which we make with multiplexers. For a recent project, we needed to measure multiple AC voltages on a Mobile Energy Storage System<\/a>.<\/p>\n\n\n\n

We chose multiplexers that are rated for high voltages, can carry a decent amount current, and are rated by their manufacturer to have their relays switched on and off plenty of times. These are mechanical systems, however, and, if you build enough test systems with multiplexers that constantly switch relays on and off, one of them will eventually fail. Any part of a factory line system failing means downtime, which can lead to losses.<\/p>\n\n\n\n

The best approach to test systems that last and deliver value is to expect that they may fail at some point. At DMC, we design tools to delay and diagnose the inevitable as opposed to ignoring it.<\/p>\n\n\n\n

To this end, we deployed our project with a diagnostic sequence and additional hardware that the client could use periodically to detect wiring and relay faults so we can fix them. There are several ways in which this idea can be applied.<\/p>\n\n\n\n

Take the example of testing a standard 120V AC outlet: we need to check that we see ~120V between live and neutral as well as live and ground but ~0V between neutral and ground.
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\nIn our case, we mapped DMM and each of the test points to multiplexer coordinate \u201cpaths\u201d and those paths to human-readable names through our custom \u201cMUX Manager\u201d library. This enabled us to control relays with Python lines like these:<\/p>\n\n\n\n

Python<\/span><\/span>