Need help to configure a two-channel acquisition using NI5154

[LCHEN5154]

What we have is a PCI NI-5154 board which installed in a newly bought DELL PC. The board was used for less than half a year. I don't see any fan on the board of NI-5154. The airflow is maintained by the fan of PC.

Should a fan installed on the PCI NI-5154 board? Why my board didn't come with one?

thanks.

Lixin

[dansch]

Hi Lixin,

The PCI-5154 does not come with any fans installed on the board itself. Generally, the operating temperature listed in the specifications document is an ambient temperature and refers to the temperature of the air at the intake of the chassis. Obviously, this is more straightforward with PXI cards since the PXI chassis is more standardized and well regulated in terms of cooling and form. For PCI cards, since they can be used in a variety of PC chassis, it is harder to ensure that they are receiving the proper airflow, and more care must be taken to ensure that they are being cooled properly. However, we do test these cards under poor conditions that are almost guaranteed to be worse than what would be used in practicality, especially if your PC is relatively new and unmodified.

Additionally, the device has thermal shutdown capabilities which should act to disable the board in the event that it exceeds a temperature which has been found to potentially cause damage. After testing, we make sure to include margins of safety as well into the determination of when shutdown should occur. More information about the thermal shutdown capability may be found here. The driver software will determine when this condition is met, and it is not necessarily always related to the particular temperature sensor that gives the value you can query and see in MAX (for instance, different components may get hotter and there will definitely be temperature gradients across the device). The main point of the temperature reading that you can query and see in MAX is to give you a better idea of when you may need to run self-calibration and account for temperature changes relative to when you last calibrated (which I highly recommend that you do, especially if you plan to operate the board at a higher temperature than what it is at now).

[dansch]

In summary, if you are operating in an environment around 32º C, you should be fine, assuming that your PC is cooling normally. The temperature that is returned to you in MAX will almost always be higher than the specified operating temperatures since that is from a physical component on the board and will be much greater than the ambient temperature that the entire board is operating in. Hope this helps!

(Had to post this separately to get under the 10,000 character limit.)

[LCHEN5154]

Thanks Daniel.

So it seems that it doesn't make lot sense for me watching the temperature output by the sensor?

[dansch · Accepted solution]

Hi Lixin,

You can definitely monitor that to make sure the temperature does not fluctuate greatly during the course of your measurements (of course, certain factors may cause this within reason). This assumes, of course, that you get the temperature to a steady, warmed-up state. As I mentioned in my post above, if the temperature changes more than a few degrees from when it was last self-calibrated, you would probably want to then run another self-calibration. Mainly, I just wanted to clear up any confusion that the board may be getting overheated if it is reading 60º C or something greater than the maximum operating temperature, because that is not necessarily the case. The best thing to do is just to establish what the temperature of the board generally runs and then check every so often to make sure that nothing really abnormal is happening such as the temperature being reported 20º higher than what is normally expected. In these situations, it may indicate that your fan filters (if you have them) need to be cleaned or something else is going wrong with your cooling.

Best Regards,