Author Topic: DAQ power supply recommendation  (Read 1662 times)

pcooper

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DAQ power supply recommendation
« on: May 03, 2019, 03:55:03 PM »
Sharing a recommendation to solve a signal noise issue created by most cheap power adapters.

Problem:
If you're using the 42AWG coax cable from the master parts list and your line is much more than 3 feet long, you'll probably need a power adapter to run the scope reliably. Most AC/DC adapters use a cheap switch-mode converter with minimal filtering to produce the DC voltage. Any noise from the power supply will be coupled into your miniscope communication signal.

I noticed the issue on my oscilloscope while trying to troubleshoot random connection failures and sudden red screens. The 1-2MHz scope signal looked relatively clean, but there was a saw tooth pattern around 100kHz when the power supply was plugged in.

Solution:
This power supply is designed to eliminate noise. Comes with an adapter that fits the DAQ, as well as international power adapters. The 9V model is practically noise-free and has no observable impact on the scope's communication signal when plugged in.

https://www.amazon.com/iPower-Supply-International-Travel-Adapters/dp/B010UYGA86/ref=asc_df_B01GNNXP0Y/

While the intermittent nature of the errors makes it hard to determine if this has made a significant difference, it certainly eliminates a variable. So far it seems to have improved stability. We have purchased one per DAQ for our lab. I recommend considering the same if you're using long cables and experiencing connection issues. Make sure to get the 9V model.