DIN rail conventions/standard - Page 1
Forum section: electronics / projects

author: PlainName
author_rank: Super Contributor
timestamp: October 07, 2020, 09:00:51 pm
content: Having suddenly taken an interest in making a project for DIN rail mounting, is there something I should be looking at regarding standards or conventions? Not the hardware side (plenty of those about) but things like whether mains always goes in at the top or bottom, intputs here and outputs there, etc.

author: rvalente
author_rank: Frequent Contributor
timestamp: October 09, 2020, 06:35:25 pm
content: You mean, boxes/enclosures to fix on DIN rail or a full electrical cabinet?AFAIK there are no standards but a few hule of thumbs and conventions.

author: PlainName
author_rank: Super Contributor
timestamp: October 09, 2020, 06:40:18 pm
content: Mostly things that fit on a rail, though any rule of thumb or convention would likely overlap.

author: Alti
author_rank: Frequent Contributor
timestamp: October 09, 2020, 07:42:22 pm
content: Quote from: dunkemhigh on October 07, 2020, 09:00:51 pmAFAIK there are no standards regarding location of inputs/outputs.The custom is that all connections are numbered (short designators), even if paralleled or not connected or are just placeholders. Remember that for a technician you cannot write on an electrical schematic "connect wire X to either P7 or P8". It has to be exactly specified, even when P7 and P8 are bridged internally. Technician does not have to know or understand what this thingy is for. Another custom is that if you only use numbers for designators then odd are inputs and even are outputs but that is more with MCBs and RCBOs.Try to avoid "o" and "O" and "i" and "I" within designators.As for Neutral / Phase on left/right there are no rules here but it would be nice to think about how this thing is assembled inside of the cabinet so that the wires do not cross if do not have to.

author: PlainName
author_rank: Super Contributor
timestamp: October 09, 2020, 08:45:39 pm
content: QuoteThanks - that's the kind of thing, yes

author: wizard69
author_rank: Super Contributor
timestamp: October 09, 2020, 11:58:57 pm
content: Quote from: dunkemhigh on October 07, 2020, 09:00:51 pmThis is one simple question that would result in answers that would take pages and pages of text to answer.Older standards such JIC (Joint Industrial Conference) existed before standards like DIN rails, but some concepts still make sense today.More modern standards include NFPA 70, especially Article 409, NFPA 79 and possible others from the NFPA.UL has its own regulations, the old being UL 508 being replaced by UL 60947-4-1. Depending upon what you are doing UL has a standard for just about everything so you need to become familiar with everything that applies to what you are doing.Then there is NEMA 250 for enclosures. Nema also has a whole bunch of standards to consider.Then there is the IEC and standards like: IEC 61131 for PLC's.Frankly a lot of reading and the list above is just a start.QuoteAgain very interesting questions and frankly like other considerations it likely depends upon local practice and regulation. For example you questions about power routing appears to be very regional. IN the USA power goes in the top and comes out the bottom of a device. On the flip side I have worked on many machines built in Europe that apparently has no standards in this regard.Actually practices between the USA and say Germany vary a lot. In the USA the practice for documentation is a ladder diagram or in some cases a schematic of the electronics type. On the other hand documentation practices in Germany are stranger than the common ladder diagram in the USA. Even the method of numbering wires and labeling devices is far different. So you need to have a good idea what your local practices are.As for the components that actually snap on the DIN rail the manufacture has some responsibility here for specifying clearances and such. If you are about to market this item as a product realize that most users require a UL acceptance or a CE mark. Otherwise some users will not touch it. If this is low volume solution do consider the various offerings of DIN rail chassis and enclosures which can help with sizing of your electronics.

author: PlainName
author_rank: Super Contributor
timestamp: October 10, 2020, 12:30:06 am
content: QuoteI suspected it might, yes.QuoteAh, well I had a 50-50 chance of getting that one right according to convention, and obviously picked the wrong one! I have no idea what the local (or global) convention for this is.QuoteNo, nothing like that - it's a pure homer. Around 25 years ago I installed a lighting controller for our garage, which converted RS232 to a multidrop protocol that the submodules could talk and supplied 12V power to them. Intelligence was provided by a laptop, which is the only thing that's ever gone wrong with it - we are now on the third laptop, but unfortunately this thing needs actual -12V input to see a mark and I have no more laptops that provide even a serial port, never mind one that gives a decent output. So I figured it was time to replace the entire thing with modern technology and do away with the laptop.The controller part is currently housed in a steel cabinet, and a DIN rail would be a better solution in that than the current separate transformers and large PCB bolted to the back and sides. Since this is essentially a one-off, never to be seen by anyone (hopefully even me once it's sorted), I could do whatever I want, but it would be better to do it 'properly' and I'll hopefully learn something useful along the way.