What is the maximum / minimum operational temperature?

  • As per the title, what are the maximum and minimum operational temperature ratings of the Pi before it stops reliably working? Could this also depend on the SD card in use?

    `while sleep 1;do tput sc;tput cup 0 $(($(tput cols)-2));cat /sys/class/thermal/thermal_zone0/temp;tput rc;done &` will display the cpu temp in the top right corner of the console. For monitoring.

    @NVRM using `watch /opt/vc/bin/vcgencmd measure_temp` (outputs new measure per each two seconds) sounds like an easier / cleaner way than your approach to constant temperature monitoring. But, I might be wrong.

    Well, those are fairly similar, the `cat` approach works on all linux, while `vcgencmd` is specific to the pi.

  • Jivings

    Jivings Correct answer

    8 years ago

    From the RPi FAQ:

    What is the usable temperature range?

    The Raspberry Pi is built from commercial chips which are qualified to different temperature ranges; the LAN9512 is specified by the manufacturers being qualified from 0°C to 70°C, while the AP is qualified from -40°C to 85°C. You may well find that the board will work outside those temperatures, but we’re not qualifying the board itself to these extremes.

    Does anyone know what the "AP" is, ie, which chip/component?

    This is the Application Processor (Broadcom BCM2835), CPU of the board.

    And it stands to reason that as the device is powered, the heat produced could factor.. IE: Starting it at -40 deg C may fail, but if it's been left running, the components should be warmer than ambient and thus not at -40. The environment should factor. -40, here I come, I'm parking some Pis outside in Canada. :)

    @Doc Funny you should mention that eh. ;) I've parked one outdoors (within tupperwear, air/water tight, but no insulation) at -20 C for a few hours, and did not notice the actual core temp (from the built-in sensor) drop below **+** 20 C.

    I have them (I call it a Piduino) running outside in an insulated control enclosure to control solar panels which follow the sun, and it gets way over 100 F in there, yet have never noticed any throttling. Not to say it isn't happening, but it doesn't seem to affect performance.

    @SDsolar 100F is about 38C, far below the heat certified, so that is consistent with the other poster.

    is there any way to detect the `LAN chip` temp, since its dead temp is much lower than `Soc Chip`, I believe the `/opt/vc/bin/vcgencmd measure_temp` command can only report `Soc Chip` temp, correct?

  • It'll go way down to < -70°C according to the article: Raspberry Pi proven to be stable when submerged in liquid nitrogen.

    Brilliant article that one is! :D Just need a steady supply of liquid nitrogen now :)

    Hmmm.. Overclocking, anyone?

  • My experience with Raspberry Pi 3: The SoC will start to throttle down at approximately 80 degrees Celsius, and will, in my experience, never allow itself to be warmer than 85 degrees Celsius. This is of course the core temperature - the temperature outside the chip will have to be much lower to facilitate efficient heat exchange.

    While you (probably, don't take my word for it) cannot destroy the SoC by leaving it uncooled, the performance will be severely impacted. (Same goes for the power supply, BTW). In our lab, we started noticing frame drops and significant degradation of video processing capability, only to find out that 1) it got too hot without the heatsink 2) the voltage dropped below 4.6V due to 5V supply wires that were too long.

    In any kind of extreme scenario, it is most likely that your processing power will decrease first, and other problems will appear much later, if ever. This can lead huge waste of time when trying to hunt down software bugs ("why is my program suddenly running so slowly?!?"), only to discover that the wires are too thin, or the heat sink is too small, so beware!

    Regarding the low boundary, you should check all the components. I recently booted Raspi3 at -12C cold and the camera did not work (first time in weeks, but other times the temperatures over night were not so low). After 15 minutes of waiting I rebooted it and it started working normally.

    Also, I think that the networking/USB chip on the board itself is not rated below 0 C. If you need such extremes, I suggest waiting for Compute Module 3, which will have range -20 to 80C, simply by not providing the problematic chip at all :)

  • I see the OP's question has been answered authoritatively, but here are my 2 cents worth of experience:

    With the basic clear plastic no-fan enclosure and heat sinks the ARM AP runs at about 50C (122F), and my Pi3 works fine. When I take off the top part of the plastic shell the temperature drops to 47-48.

    So my conclusion is that the enclosure is not causing any measurable harm in this regard.

    The command to return the CPU temperature in stdout is vcgencmd measure_temp


    I see in comments that uhoh mentions that if you want to use the temperature in a Python program, the command os.popen('vgencmd measure_temp').read() will return the textual version of the temperature number.

    ------------------------------------------------------

    Here is the way I use Popen to get the temperature into an integer variable:

    from subprocess import Popen, PIPE
    .
    .
    .
    cmd = 'vgencmd measure_temp'
    p = Popen(cmd,stdout=PIPE, stderr=PIPE, shell=True)
    stdout, stderr = p.communicate()
    
    CPUtemp = int(stdout)
    .
    .
    etc
    

    The above is taken from this code:

    Ping a website and have an output turn on if online/offline?

    This post shows how to use fping in a few different ways even though the results come in as stderr

    Also includes a cradle-to-grave example which makes use of the data and plots it live as it comes in. It shows Python and gnuplot. We don't see enough of these whole-system examples here.

    just make sure there is good air movement in environments with very high temps to begin with :)

    Excellent point. My room temperature is 75F which is just under 24C, and the door is open to outside so there is good air flow.

    Why would you have Pi3 with "light load"? Then you may use Pi 1 and have no problems whatsoever.

    I changed my mind about the enclosures with the fans. To control the noise I run the fan at 3.3 Volts. They work great. I now have them on all my Rpi3B systems. FYI, most fan enclosures come with only 2 heat sinks. I went ahead and bought extras so I can put one on the chip underneath. The enclosures have a cutout ready to accept them.

    This is very helpful! (will up vote in 12 hours when my quota for the day expires). It seems that `os.popen('vcgencmd measure_temp').read()` makes the temperature (text) available within Python as well. as does `commands.getstatusoutput('vcgencmd measure_temp')[1]`

    TNX for the Python commands. That approach to using `os.popen` and `.read` like that could come in very handy. Not to mention `commands.getstatusoutput ... [1]` I tend to use Python with external commands a lot but hadn't run across either of those. Well done. btw, the more questions you answer the more points you will get and the restrictions will get lifted pretty quickly. This particular SE is a tough crowd, but they definitely recognize valuable contributions to the database.

    I maxed out on up votes today; while I spent several hours looking for some things I kept running across (what I felt to be) helpful posts with zero votes. I haven't figured out what makes some SE sites more generous and others not as much.

    The trick is to ask a good question with lots of info on what the problem is, how you tried to solve it, then posing a question that can fit in the title. That is #1. #2 is to search through past questions (like this one) and add a decent answers with specifics like links to outside websites (and always type in an excerpt from each one to protect against link-rot). Always remember that the goal here is to build a database that people Google into and find their answers quickly. Question titles and specific detailed answers is the way to earn points on any SE site. . And have fun!

    One more thing. Figure out who the best people are on the various SEs are and look for their posts. You can find them by going through past questions and looking at the questions with many high votes. Once you find one (Here I suggest `goldilocks`) you can search for their name. Others here are true wizards. Like `joan` She has an amazing website. She wrote the `pigpio` library. http://abyz.me.uk/rpi/pigpio/ When I started I would earn 2 points at a time by going through old questions and adding a relevant tag or two. It takes time but works. Plus you will learn a lot.

    By the way, as I work and need info, I very often Google a question then find a Q&A in one of the SEs that are from 2013 or so has the precise thing I need. And I `ALWAYS upvote both the question as well as the answer` It is most helpful when the answer gives me everything I need, even if it references a web site where the answer came from. `I like going from Google to having my answer in under a minute` It happens a lot. SE has been around a long time. So in comments I always annotate the correct answer by saying something like "Thank you from March 2018" to remind people how it's used.

    if you're using raspbian why not just read /sys/class/thermal/thermal_zone0/temp? Divide by 1000 to get degrees C. Seems to have more precision compared to vgencmd as well.

  • The following is a little outside of the question, but a general use case that might give some ideas.

    This can be adapted to any kinds of inputs, gpio sensors, internet datas.

    How to graph the CPU temperature overtime?

    Install gnuplot

    Gnuplot can graph datas in the terminal, does not require any X server and use very little ressources.

    It works smooth even on the slowest raspberry pi's model 1/zero.

    sudo apt install gnuplot
    

    Script example to build a gnuplot file:

    temperature script to store the data overtime.

    #!/bin/sh
    echo $(date +%s ; cat /sys/class/thermal/thermal_zone0/temp) | tee >> temperature.plot
    

    Give execution rights to this script:

    chmod +x temperature
    

    Detach and run in 1s loop till next reboot:

    nohup watch ./temperature &
    

    Later, graph the datas:

    gnuplot -e "set terminal dumb $(tput cols) $(tput lines);plot 'temperature.plot' using 0:2 with lines"
    

    enter image description here

    This is a barebone example, temperature in Celsius * 1000, and seconds since the start, to be extended in your own scripts suite.

    To kill the watch loop, killall watch

    Happy hacking ;)

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Content dated before 6/26/2020 9:53 AM