# Calculating the Heat Dissipation of a CompactRIO

Updated Jun 15, 2019

• cRIO-9031
• NI-9145
• IC-3173

## Issue Details

• I want to put a CompactRIO (cRIO) in a tight enclosed area and I'm concerned about it overheating. I would like to know how much heat it gives off. How do I calculate this?
• I'm planning on putting a cRIO into a small enclosure. I need to know the maximum amount of heat the cRIO will add into the enclosure. How can I find this?

## Solution

There are three ways to determine how much heat will be dissipated from a cRIO. All three are related to calculating the power used by the cRIO, and then computing the heat conversion from that.

You can calculate the heat dissipation from the maximum power consumption from the cRIO chassis, average consumption of the chassis and modules, and lastly by empirically testing the power consumption of cRIO and modules. Each one has an ascending degree of accuracy for the heat dissipation calculation, but also has a descending safety factor.

Note: Keep in mind that heat output is measured in British Thermal Units (BTUs). You can convert watts to BTUs/hr with the following formula:  (watts*3600)/1054 = BTU/hr

Method 1: Using Maximum Power Consumption from the module
1. Find the manual for your device from ni.com/manuals
2. Search and find the manual of your cRIO Chassis.
3. Find the Maximum Power requirements of the cRIO in the specifications. For example, the cRIO-9031 has a maximum power requirement of 40W.
4. Convert the watts to to BTUs/hr.

Method 2: Using calculated power being used by the cRIO
1. Add up the power output numbers for the controller, backplane and the modules that you are using for measurement. (The actual power number is always less than the maximum power input outlined)
Example system:
• cRIO-9014 (Controller) - 6 watts
• cRIO-9104 (Chassis) - 3 watts
• C-Series Modules
• NI-9205 - 0.625 watts
• NI-9263 - 0.625 watts
• Two NI-9401 - 0.58 watts each
• NI-9474 - 0.66 watts
• NI-9237 - 0.74 watts
Power = (6 + 3 + 0.625 + 0.625 + 2*0.58 + 0.66 + 0.74) watts or 12.81 watts.

2. Convert the watts to to BTUs/hr.

Method 3: Using the measured Power from the cRIO
1. Follow instruction in the following tutorial to measure exact power output of your own cRIO: Measuring the Power Consumption of CompactRIO Systems
2. Convert the watts to to BTUs/hr.