Maximum Current drawn by PXIe-7976

[muhammadjb]

I am acquiring some data on NI PXIe-7976 FlexRIO uisng an adapter module which will be further processed on FlexRIO. I want to know how much current will FlexRIO draw (which is mounted on PXIe-1082 Chasis)? As per Datasheet of FlexRIO, maximum Power Requirements depend upon the connected Adapter module and VI running on FlexRIO, however, their will be a limit to the maximum power requirement above which it won't work or will be damaged. Where can I find such information? Does the power requirement specified on the FlexRIO datasheet are maximum power requirements? If not, how can I calculate mine? 

[VintageWillis]

Hi,

Do you have a model number of the adaptor you are using?

here is some of the total/max power draw of a few adaptors to give you an idea:

Power

Total power, typical operation

NI 5731 ..........................................................1.7 W

NI 5732 ..........................................................2.1 W

NI 5733 ..........................................................2.6 W

NI 5734 ..........................................................4.5 W

[BauerPower · Accepted solution]

Hi! I assume you're working on power budgeting for your system? The max current specified for the 7976R is the max current that the module can draw from each of the backplane power rails, and those maxes are independent of the adapter module used. The adapter module power is supplied by the 7976R, not the backplane.

Therefore, per the 7976R datasheet, the max power that you could draw from the backplane is 36W on the 12V rail and 9.9W on the 3.3V rail. Actual power draw is highly dependent on the logic executing on the FPGA. Unless your FPGA design is very large and executing at a high clock rate (>=200 MHz), it's very unlikely that you'll ever hit those max numbers. Most complex designs I've seen on the K410T FPGA burn ~20-25W and the adapter module can draw a maximum of 6W, depending on the adapter module. If you have a 7976R, you can measure your power draw using an FPGA I/O node on the FPGA block diagram: http://zone.ni.com/reference/en-XX/help/372614J-01/target5devicehelp/prog_ex_io_status_7s/

As described above, this number will include the adapter module power draw.