# Using Bus Power for the PCIe DAQ

The 900 MS/s version of the Axsun PCIe DAQ (AXP52013-x Rev C or later) can *optionally* draw its power from the host workstation's PSU (power supply unit) via its PCIe edge connector plugged into the workstation motherboard, ***instead of*** an external 12V [AC/DC adapter](https://docs.axsun.com/axsun-knowledge-base/ref-manual/ss-oct-laser-engine/accessories#ac-dc-power-adapter-and-ac-power-cord) plugged into the power input connector J3 via the [Power-Y cable](https://docs.axsun.com/axsun-knowledge-base/ref-manual/ss-oct-laser-engine/accessories#power-y-cable).

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**NOTE:**  It is the user's responsibility to ensure that the host's PSU is adequate to supply up to 25 W to the Axsun PCIe DAQ in addition to the PSU's other connected loads.
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To configure the DAQ for PCIe bus-powered operation, install two 2.54 mm jumpers (aka shunts) on the 4-position vertical header J14, which is located in proximity to the PCIe edge connector.  The installed jumpers **must** be oriented as indicated by the green rectangles in the photo below.

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**WARNING:**  Never attach an external power supply (e.g. 12V AC/DC adapter) to power input connector J3 while jumpers are also installed on J14 on the PCIe DAQ.  If J14 jumpers are installed, we recommend installing an unwired "dummy" connector (Molex 43025-0600) into J3 to avoid inadvertently connecting both power sources concurrently.
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&#x20;Jumpers are not supplied by Excelitas, but can be easily procured from various sources, such as [here](https://www.mouser.com/ProductDetail/TE-Connectivity/530153-2?qs=ZDXmSm13591aaDbZi3by6A%3D%3D).&#x20;

<figure><img src="https://3144558317-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-LP1icDU_wgMhPOYQY7u%2Fuploads%2F78JaSD8irMYG0c1OzmTp%2Fimage0.jpeg?alt=media&#x26;token=e4679612-b693-4aba-b2d0-8ebf005984bb" alt=""><figcaption><p>Default configuration with no jumpers installed on J14; power must be delivered to DAQ via external supply on J3 connector.</p></figcaption></figure>

<figure><img src="https://3144558317-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-LP1icDU_wgMhPOYQY7u%2Fuploads%2FijUE5w0K7J4iVD2iPbZX%2Fimage1.jpeg?alt=media&#x26;token=6a44a8fc-bad2-4cf2-a6a1-1de3512e1945" alt=""><figcaption><p>Two jumpers installed on J14 in the correct orientation (green rectangles); DAQ will be powered by workstation PSU via motherboard.</p></figcaption></figure>
