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Legacy M-Series 2-wide carrier - rudimentary question

The power supplies in a redundant controller deployment - are they totally independent of one another or do they load share / back up each other? So when I pull a power supply, it should only affect the controller next to it . . . in my case it would be the "Standby" controller's power supply. It only affects the "standby" correct?

My concern is around if they did have some redundancy, one might have a "weak" one on the primary which would potentially fail when the "backup" was pulled . . .

John Rezabek
  • fairchdm
    I can't answer your question to the detail, but I've replaced several redundant power supplies online without issue.
  • Andre Dicaire
    First, M-series is not a legacy product. It is fully supported and actively sold, with new IO cards and Controller hardware introduced in v12 and v13. Just sayin'.

    The System Power supplies provide 12 V power for the IO cards and 5 volt power for the associated controller. If the IO power requirements exceed the capacity of a single System Power supply, you could lose power to the IO by pulling one of two supplies. Proper design of the IO subsystem should identify this and it can be remedied by adding a third power supply or by injecting 12 VDC power in the IO subsystem appropriately, as discussed in BOL.

    Assuming your IO power requirements do not exceed one System Power supply, you can pull one without affecting the IO.

    Redundant controllers each have one power supply installed on the same 2 wide supply, and each power supply in this arrangement powers its associated controller that shares the back plane. Pulling a controller powers down that controller.

    A Simplex controller can have redundant System power supplies by installing a second 2-wide backplane to the left of the controller carries, and installing a second Power supply in the right hand slot. This arrangement allows both power supplies to provide 5 volt power to the controller in the left hand carrier. Again, if the IO power requirements do not exceed the single System Power supply max current, you can pull either supply and the simplex controller will continue to run, along with the IO.

    If you have a redundant controller pair, you can add a third 2-wide carrier and install a third Power supply to increase IO power, making sure you are not exceeding the IO carrier max power capacity. If you install this third supply in the right hand slot, it will provide redundant 5 volt power to the left hand controller. The right hand controller will remain with simplex 5 volt power from its system power supply.

    If you're not sure what your IO power requirements are, you'll need to do the calculations found in the BOL worksheet, based on your IO card types.

    Andre Dicaire

  • John Rezabek

    In reply to Andre Dicaire:

    So - should one be confident that a (single) green-lighted power supply that's been energized since 1999 will support the number and type of cards that are OK per BOL, when it's companion is pulled?
  • Andre Dicaire

    In reply to John Rezabek:

    Hmmm.  Should work.  But if you are concerned.  Force active controller to right.  Then remove stand by controller and install a new supply in pls e of controller.  That puts three supplies in play.

    Then replace the left carrier old supply.  And then restore redendunant standby controller.

    Now you have new supply for when you replace the right hand carrier's supply.

    Note that this only slightly extends your simplex time your are in simplex operation.

    Andre Dicaire

  • John Rezabek

    In reply to Andre Dicaire:

    So - I should have re-read your instructions caarefully before attempting this . . .

    First, having removed the ±12VDC power from the old power supply, when we landed it on the new power supply, it would not "green light". A DVM revealed that while all our "bulk" 12 VDC redundant power supplies (VE5004) read 12.0 VDC at the power supply, the DeltaV power supplies were only seeing about 11 VDC at the terminals (this evidently was not low enough to cause any of the old 12V-12V power supplies to "red light). We adjusted all of the bulk power supplies to deliver about 12.8 VDC and we were able to get a green light on the new one.

    We removed the "redundant" controller and installed a new DeltaV power supply in its place. We were then able to replace both remaining DeltaV power supplies without incident. The active controller being in the 2-wide carrier closest to the (conventional) IO. Key thought being we did not reinstall the redundant controller and force a switchover.

    Next controller. Active controller is to the left (furthest from the IO). Standby pulled and "backup" power supply installed in its place. One power supply pulled & replaced, all is well. As soon as we pull the second - next to the controller - it red lights as does all the IO. After quickly reseating the card, power was back but the controller came back as "no configuration". While the plant was "mostly" down there was a little excitement.

    So I assume the lesson is - redundant power supplies in an M-series 2-wide + 2-wide carrier are not totally load sharing? On re-reading Andre's note, I see some details that would confirm this is the case. Did the first one "work" only because the active controller was on the right?

    Going off to consume a refreshment now . . . Cheers,
    John

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