Chassis/Enclosure Temperature

[Nathan_B.]

I have an sbRIO-9632 and I have a few questions regarding the allowable temperature range for the device.

I would like to know is where the "Chassis Temperature" is measured?  The sbRIO states that the maximum ambient temperature of an enclosure is 55 °C.  I would assume that the fact that the "Chassis Temperature" sensor is on the board that it would not be an accurate measurement of the ambient temperature.  So, what temperature can I consider a maximum temperature threshold when monitoring the chassis temperature?

Unfortunately, I'm giong to have this in a relatively small encloser (because of an extremely dusty environment) and I need to determine the consequences of this.  I would like to avoid requiring an active cooling system (running air through the encloser) because of the dust.

Also, from what I've noticed so far, the RT processor seems to get the hottest, is there any reason why I would need to consider adding a heat sink to it?  The manual only talks about heat sinks for the 24V outputs which this board does not have.

Thanks.

[Dave.C]

Hi Nathan_B,

The board is tested in a temperature controlled chamber where the temperature ranges between the limits indicated in the specifications for the device.  That said, the 9632 will perform in environments ranging between -20 °C and 55 °C.  

There is some additional documentation on this topic found here.  Although it doesn't specifically address the 9632, it does show that a heat spreader was helpful for keeping specific components cooler.

That said, I don't think it would hurt to add one, but whether it's necessary is going to depend on the characteristics of your enclosure along with the power you plan to output from the device.  Worst case would involve the maximum power output all going to heat the environment.  

Have you done any testing? 

[Nathan_B.]

I've not done any real heat testing as the enclosure has not been designed completely yet and I'm still testing on the starter kit.  I do know that there will not be all that much space (unlikely be able to put a full heat spreader on it) and that it will be oriented vertically.  I plan on getting the enclosure made of thin aluminum.

I would like to know if the "Chassis Temperature" is a value that I can use to monitor the thermal safety of the board though.

[Dave.C]

Hi Nathan_B,

The sensor monitored by "Chassis Temperature" is on the board of the sbRIO so it can be used to monitor the safety of the board.