Damian Posted July 23, 2020 Report Share Posted July 23, 2020 A bit of a weird situation with the unit in title. It is installed and working as you would expect (new application, just programmed this week), but I noticed some odd noises coming from it. I disconnected all the connectors and cables except for the 24VDC supply and it still makes the noise. When I cycle power to it, it is quiet up until it completely finished booting and then runs the application. As soon as the application starts running, the unit starts making the crackle sound again. There are not any relay IO, so it can't be a chattering contact. It is hard to tell if it is the speaker or something else. Attached are a couple videos where hopefully you can hear the audio OK. Any ideas on what it might be? UniStream Snap Crackle Pop.mp4 UniStream Crackle.mp4 Link to comment Share on other sites More sharing options...
MVP 2023 kratmel Posted July 23, 2020 MVP 2023 Report Share Posted July 23, 2020 Hi, This sound like internal DC/DC. Maybe some broken or not fixed (not glued) ferrite act as sound speaker driven by internal or external power supply current modulated by PLC program cycle. For recognize it is internal or external modulated current please use another power supply. Link to comment Share on other sites More sharing options...
MVP 2023 Ausman Posted July 23, 2020 MVP 2023 Report Share Posted July 23, 2020 As it is working, I am with Kratmel. I've had power supplies make very odd noises, but I then don't trust the unit and replace it. However.... 9 hours ago, Damian said: (new application, just programmed this week) Ensure that the installers didn't let any swarf etc into the unit. I've had many plcs stuffed by "experts" relocating equipment and drilling/cutting holes willy nilly without any covers over all the control gear at all, with subsequent failure. "Aus, it doesn't work anymore!" "That's because you are a pack of dills". I used to work with a PLC brand that came with paper protection all over the vents, explaining about removal after ALL works were finished. Great idea. Time to remove a cover to see what is really going on, me thinks. 😨 cheers, Aus Link to comment Share on other sites More sharing options...
MVP 2023 Joe Tauser Posted July 23, 2020 MVP 2023 Report Share Posted July 23, 2020 25 minutes ago, Ausman said: That's because you are a pack of dills 😆 I so want to visit Australia, if for no other reason just to tell everyone I'm a seppo and then sit back and listen to the colorful abuse. Joe T. Link to comment Share on other sites More sharing options...
Damian Posted June 11, 2021 Author Report Share Posted June 11, 2021 I never circled back on this. Mea Culpa. Total operator error on the programmers part. No problem with the hardware at all. Link to comment Share on other sites More sharing options...
MVP 2023 Flex727 Posted June 11, 2021 MVP 2023 Report Share Posted June 11, 2021 1 hour ago, Damian said: Total operator error on the programmers part. Being one of those programmers with plenty of operator errors under my belt, I just have to know what this one was. Link to comment Share on other sites More sharing options...
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