STX16803 current surge?

Discussion in 'STX and STXL Series Cameras' started by blackdragon72, Jun 25, 2020.

  1. blackdragon72

    blackdragon72 Standard User

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    According to user manual, pin 2,3,4 are ground, pin 1,5,6 are 12V. I measured AC adapter output, pin 1, 5 are 12V, pin 6 has no output. pin 2 and 4 seems tied off internally (no resistance between 2 and 4), pin3 seems open.

    Should pin 3 and pin 6 be left open when I build my own cable?
     
  2. Doug

    Doug Staff Member

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    No. Connect all three. That is safest.
     
  3. blackdragon72

    blackdragon72 Standard User

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    I connected only 2 pins (pin2 and 4) and left pin 3 open.

    The problem is solved if I connect all 3 ground pins. Not sure how connecting all 3 pins to ground helps but it does fix the issue (pin 2-4 seems short together internally in CCD).
     
  4. Doug

    Doug Staff Member

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    If you only connect only one pin for +12V, you are exceeding its rated current capacity. It might work well enough now, but it may also be damaged long-term.
     
  5. blackdragon72

    blackdragon72 Standard User

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    I connect 2 12V, same as AC adapter outputs.
     
  6. blackdragon72

    blackdragon72 Standard User

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    BTW, what is the rated current capacity for each pin?
     
  7. Doug

    Doug Staff Member

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    Okay if you have at least 2 connected on each side, it should be okay, but 3 is better.
     
  8. blackdragon72

    blackdragon72 Standard User

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    Got it.

    But I still dont understand why connecting only 2 ground pins would blow the fuse, while connecting all 3 works fine. The AC adapter has only 4 pins anyway (prior to 4 ->6 pin cable)
     
  9. Doug

    Doug Staff Member

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    It won't blow the fuse, unless you short the connector to the shell.
     
  10. blackdragon72

    blackdragon72 Standard User

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    Related question.

    I measure STX power adapter.
    4-pin DIN shield is tied to ground, however 6-pin DIN shield is not.

    Does it really make any difference? ie, can I use 4-pin DIN power adapter directly to another equipment, if it happens to have same connector/pin assignment? Or it may not be safe since shield and ground are tied together.
     
  11. blackdragon72

    blackdragon72 Standard User

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    The reason is that I want to check whether I can plug in STX power adapter to Paramount MyT aux power in. And I am going to build/buy another cable (or use SBIG 4-pin to 6-pin cable) to connect 4-pin aux port to camera.
    Paramount Mount is simply becomes an extension cable. Question:
    - Is it Ok to connect STX 4-pin output directly to the mount? Does shield tieoff to 0v matter?
    - Does shield tie to 0v matter on camera side if I use DIY cable?
     
    Last edited: Sep 9, 2020
  12. Colin Haig

    Colin Haig Staff Member

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    You cannot do this - it is unsafe and a fire hazard.
    The Paramount MyT wiring and connectors are insufficient and will not handle the current.
    The STX package can draw nearly 10Amps, 120Watts, and that will overheat the connectors on the MyT.
    The DIN plug can handle a maximum of 2 amps per pin, so 4A is about the maximum for the MyT, using 2 pins for +12V, and 2 for 0V.
    Further, the 18-gauge wiring in the Paramounts will result in a voltage drop.
    Although those connectors are a nice idea, Software Bisque did not design them to handle this level of camera.
     
  13. blackdragon72

    blackdragon72 Standard User

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    SB manual says it can carry about 7.5A (or 8A since they have an adapter to 5A+3A DC plugs). It does not support full 10-A but 8-A is still good for my system.

    Isnt SBIG STX power adapter using the same 4-pin DIN? How does it support 10A?
     
  14. Doug

    Doug Staff Member

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    The 4-pin cable connector is not a DIN. It is rated for higher current.

    We do not recommend using the built-in Paramount wiring. If you get too much voltage drop the cooler on the STX will shut down automatically.
     
  15. blackdragon72

    blackdragon72 Standard User

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    Maybe I used the wrong term.

    This is what Paramount manual says:

    The “stock” through the mount cabling for this connector uses 18-gauge AWG wires to carry relatively heavy DC loads and the 4-pin Kycon KPPX-4P series connectors (Mouser part number 806-KPPX-4P) are rated to carry a maximum of 20 volts at 7.5 amps.

    I think the connector is same as STX 4-pin connector, at least it looks so.
     
  16. Doug

    Doug Staff Member

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    Okay, I haven't looked closely at one of the newer Paramounts. You can certainly give it a try. If the camera's cooler shuts down unexpectedly when running at full power, it would be due to voltage drop in the cabling.
     
  17. Colin Haig

    Colin Haig Staff Member

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    If you decide to build your own cable and go direct to the MyT 4 Pin Kycon connector and not with a DIN, the maximum the Kycon will take is 7.5A not 8A.
    Here's the data sheet for the connector Bisque uses (It's a KPPX-4 set):
    https://www.kycon.com/2013Catalogpage/DC Power/KPPX.pdf
    If you use one of the premade cables which goes from that to a DIN, the DIN plugs are limited as previously mentioned.

    From the Software Bisque GEM manual, some other guidance:
    The Paramount Robotic Telescope System User Guide
    Paramount MYT, MX, MX+ and ME II German equatorial mount models
    Revision 2.13
    July 2019

    Page 34:
    "The Paramount through the mount cable conduits are intended to house cables that carry low voltage and relatively low current direct current (DC) power, only.
    • Software Bisque recommends installing through the mount cables that carry a maximum of +12V DC, 5.0A (60W max)."

    I really don't recommend running STX power through the internals of the MyT.
     
  18. blackdragon72

    blackdragon72 Standard User

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    Thanks Doug, Colin.

    I need to confirm with SB.

    On the other hand, suppose current limit is fine, does it really matter if metal shield is tied off to 0v? I think STX 4-pin does tie off but 6-bin does not.
     
  19. blackdragon72

    blackdragon72 Standard User

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    Colin,

    I think it says that if you use through the mount cable method (which run the cable completely in the mount), it is 5A. If you use Kycon connector, it is 7.5A,
     
  20. Colin Haig

    Colin Haig Staff Member

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    I suggest you talk to Software Bisque to get some clarity. Our experience has been that STX cameras require external cabling on any of the Paramounts for best performance.
     

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