greml1n Posted August 24, 2016 Report Share Posted August 24, 2016 Should I be grounding the power supply 0V. The wiring guidelines for the modules suggest that it should be earthed. I have seen many arguments for and against Link to comment Share on other sites More sharing options...
HigHTech Posted August 24, 2016 Report Share Posted August 24, 2016 Should I be grounding the power supply 0V. The wiring guidelines for the modules suggest that it should be earthed. I have seen many arguments for and against I never do it (since 2001 and a lot of Unitronics PLC installed that way in that time) and still not having a problem. But that´s just my personal experience. This is your first project? Link to comment Share on other sites More sharing options...
greml1n Posted August 24, 2016 Author Report Share Posted August 24, 2016 No, not my first project. I have not been grounding the 0V either but noticed the other day when testing my program with a 4-20 calibrator that my inputs were sweeping up and down, about 1/2 mA total. My calibrator output is rock solid since I checked it with a separate meter. When I grounded the 0V on the power supply the sweeping stopped and the input was rock solid. I guess its dependent on the bonding in the building the PLC is installed in and I should handle it on a case by case basis? Link to comment Share on other sites More sharing options...
HigHTech Posted August 24, 2016 Report Share Posted August 24, 2016 No, not my first project. I have not been grounding the 0V either but noticed the other day when testing my program with a 4-20 calibrator that my inputs were sweeping up and down, about 1/2 mA total. My calibrator output is rock solid since I checked it with a separate meter. When I grounded the 0V on the power supply the sweeping stopped and the input was rock solid. I guess its dependent on the bonding in the building the PLC is installed in and I should handle it on a case by case basis You need to have a good earth on the system. That´s all I check, if the earth is not a good one, then problems with analog signals are normal. Link to comment Share on other sites More sharing options...
CarloTruax Posted September 16, 2016 Report Share Posted September 16, 2016 Hi..i am a new user here. As per my knowledge for the proper functioning the 0V should be connected to ground. Otherwise you will face different type of problems, mainly it effects the functionality only. pcba board Link to comment Share on other sites More sharing options...
MVP 2023 Joe Tauser Posted September 19, 2016 MVP 2023 Report Share Posted September 19, 2016 I usually connect 0V to ground because it makes troubleshooting easier - clip the negative of your meter to a DIN rail and you can poke around with the positive lead. +1 on what HigHTech says - make sure you have a really good earth ground or you'll have problems with your analog signals if you ground the DC power supply. Joe T. 1 Link to comment Share on other sites More sharing options...
MVP 2023 Ausman Posted June 8, 2020 MVP 2023 Report Share Posted June 8, 2020 Bumping an old thread for comments from all on something new. Recently I had to replace an old IDEC DIN rail supply and due to both urgency and enclosure depth limitations I had limited purchasing options. Ended up the best was a Mean Well but it did not have an earth. It was an HDR-30-24 and it looks like the entire range of this series is the same configuration, being double insulated. I haven't actually purchased a DIN rail supply like this for a few years, so maybe earths got dropped a while back. Being double insulated makes me intrigued about best practice regarding commoning of the negative, and also earthing practices etc, as it is in some ways now a fully isolated, floating supply. Love to hear all the viewpoints on this "new" variation. I can't find any information on the MW site regarding best practice, but feel sure that running it not connected to earth is going to upset a host of reading types that rely on miniscule amounts of electricity. In this particular case it doesn't matter, but I see the potential for it to be an issue. cheers, Aus Link to comment Share on other sites More sharing options...
MVP 2023 kratmel Posted June 9, 2020 MVP 2023 Report Share Posted June 9, 2020 Hi Ausman, in this case i found many different solution on real machines. As for me no earth contact on power supply is MW idea for cost saving. Now i see both variant of MW PS - old MDR with EARTH and new without. Old wariant is approx 10-15% bigger price. But I think the grounding (or not present gronding) of the primary side doesn't matter if the power supply has a grounded minus of the secondary part. Maybe you can find useful this link. https://www.klocknermoeller.com/klockner.moeller/Wiring_Manual_English.pdf start from p.1-17. In this document is presented OV connection to the ground with waveforms: https://literature.rockwellautomation.com/idc/groups/literature/documents/rm/gmc-rm001_-en-p.pdf p.110. Link to comment Share on other sites More sharing options...
MVP 2023 Joe Tauser Posted June 9, 2020 MVP 2023 Report Share Posted June 9, 2020 That AB document is one hell of a treasure trove of information. There's stuff in there I knew, stuff I didn't know, and stuff I was wrong about. I'm especially impressed that they included the waveforms. Thanks for posting the link! Joe T. Link to comment Share on other sites More sharing options...
MVP 2023 Ausman Posted June 9, 2020 MVP 2023 Report Share Posted June 9, 2020 Thanks Kratmel, as Joe says there's a lot of great info in that AB pdf. cheers, Aus Link to comment Share on other sites More sharing options...
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