Are there any members who are experts on Electrickery

Discussion in 'DIY and Makers Spot' started by Falloutboy, Oct 11, 2019.

  1. Falloutboy

    Falloutboy Member

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    And I say Electrickery because a lot of it which is gobbldygook to me.

    • I am presently building a combination Network Attached Storage Raid 6 / Home brew 40Gb Switch using multiple Mellenox cards, a Broadcom 9361-8i and SAS Expanders on a Supermicro X10DRX motherboard which will hopefully fit in my Xigmatek Elysium case to run 16 of the SAS 3 drives and the other 12 in an iCute Super 18 case via an expander with all the proper SFF cabling between them.

    The problem started of as wanting to remote start the 2nd ATX power supply in the 2nd case which would have no motherboard and I got an answer for that but someone else made a comment that I had not seen until the question was closed and I need to determine what if anything I need to do. Note I don't ever intend to have only one PSU connected but it would be nice to have the system protected for such an event.

    There comment was as follows
    "This would not be my first suggestion. It would be better with some isolation like two schottky diodes. While the PS_ON signals are inputs, their actual implementations can vary between PSU models and manufacturers. Connecting PS_ON wires together means there are two inputs loads for the motherboard to drive. But each PSU will pull its own PS_ON signal high to its own standby 5V supply. The voltages have tolerance, so current may flow from higher voltage supply to lower voltage supply via the PS_ON pins. When one PSU has mains unplugged, it might clamp PS_ON to GND, turning the other PSU on"

    Would the comment be a problem? should I add schottky diodes? or would it be even better if it were opto coupled which would mean no physical connection?

    Here is a diagram Remote ATX power.png
     
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  2. Philip Brink

    Philip Brink New Member

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    An atx power supply only needs to have a connection between two pins on the 24 pin motherboard connector to turn the psu on. The psu will supply the signal.

    An easy option to chain two psus is a relay. Use the power from a spare molex connector to switch on a relay between the two pins on the second psu. When you turn off the main psu, power cuts out and the connection cuts out, turning off the second one. They are also isolated from each other because of the relay.

    If you want, put a bypass around the relay that is connected to a toggle switch so it can be turned on without psu1 power.
     
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  3. MiniKnight

    MiniKnight Well-Known Member

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  4. BeTeP

    BeTeP Active Member

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    People tend to over-complicate things. If all what you want is for your secondary system to power on and off at the same time as your primary one - just get a $20 master controlled power strip. You will need to connect the PS_ON pin of the secondary system to the ground and leave it connected for it to work as requested.
     
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  5. Falloutboy

    Falloutboy Member

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    This sounds good, I do have two queries though.
    Firstly if the first machine goes into a sleep state will the 2nd machine stay on, if it will then this is undesirable.
    If you power the 1st machine down will the 2nd follow suit?
     
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  6. Falloutboy

    Falloutboy Member

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  7. Philip Brink

    Philip Brink New Member

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    Im pretty sure power is turned off to the molex plugs, but a simple check volt meter would make it certain. Im away from my system for the weekend.

    If the voltage drops, then the relay should switch off, assuming it turns on when power is applied. I cant remember for certain, but i think there are options for each.
     
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  8. kapone

    kapone Active Member

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    I'm confused...

    Daisy chaining startup/shutdown of secondary power supplies is not rocket science. All you need is ~$5ish and buy any of the "add2PSU" type of boards.

    s-l1600-29.jpg

    You plug the secondary PSU into the ATX connecter, run two wires between the machines (+12v and GND, no need for 5v) and connect that to the molex connector on the board.

    Done.

    If the "master" computer is shutdown, the secondary power supply is shutdown. If the master computer goes to sleep, the secondary power supply is shutdown. And the reverse when things are started or woken up.

    How do you think I'm powering the expander boards and HDDs in this chassis that I'm using? There's 3 power supplies in there, daisy chained to the main power supply.

    IMG_0347.jpg
     
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  9. maes

    maes Member

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    You would definitely want 5V instead of 12V for the exact board picture you posted, however. That's a 5V relay. ;)

    Out of curiosity, what's that chassis you're using with the 3 power supplies? Looks massive.
     
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  10. Markess

    Markess Active Member

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    If the non-IPMI version of the boards that @MiniKnight mentioned would work for you, I know forum member @sfbayzfs had some of the CSE-PTJBOD-CB1 (similar to the one on Amazon, but with more fan control options) for sale for a lot less than Amazon, although I don't know if he still has any.

    I believe he's willing to ship internationally (but I don't want to put words in his mouth). Of course, I have no idea how much to ship to NZ, but at least they are pretty small and light.

    Link to an article on the main site about them: https://www.servethehome.com/supermicro-cse-ptjbod-cb1-jbod-power-board-diy-jbod-chassis-made-easy/
     
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  11. kapone

    kapone Active Member

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    The board picture I posted is just an example. There's several derivatives of it that use +12v or +5v depending on the relay. The one's I use, use +12v.

    The chassis you're seeing, is the Chenbro NR40700/Cleversafe Slicestor 1440 48 bay chassis.
     
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  12. sfbayzfs

    sfbayzfs Active Member

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    Yes, many of them found new homes, but I still have several of the CSE-PTJBOD-CB1 left for sale, and I can ship internationally, please DM me with an address if interested!

    The USPS Priority Mail small flat rate boxes can hold two easily, and up to 4 if I repack them creatively, and it looks like it costs US$37.70 to send one of those to NZ.

    In case these are more appealing, I was about to put a couple of the CSE-PTJBOD-CB3 (the new fancy version with IPMI, 10 fan headers, etc.) which I think I have decided not to retrofit some 847 JBODs with up for sale, I was thinking $120 each shipped in the US including an aftermarket 0.5M ethernet extender cable w/ mounting screws for the remote jack end. (Hopefully I will have time to post a big update to my FS/FT/WTB list this weekend)
     
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