1: switch off temperature
The switch-off temperature of the safety function is 105 degrees. That is below the specified temp in the data sheet and thus protects the HW.
2: operation Temp
I am wondering what then the right limits are. For example we give a CPU warning at 89 degree. But is that a good temperature?
That’s OK. The customer’s control cabinet will probably be around 40 degrees.
I dont know what the temperature in the cabinet is at that moment. But we have many customers that have the CPU on that temperture.
The temperature provided in the IO assignment is only a guideline. If the suspicion that the customer has a temperature problem in the control cabinet is confirmed, the control cabinet environment should be measured. B&R provides the X20 modules: X20CMR010, X20CMR011, X20CMR111,
X20CMR100 for the analysis. These modules were designed for this application.
https://www.br-automation.com/de-at/produkte/io-systeme/x20-system/sonstige-funktionen/x20cmr010/
To show that these temperatures are typical for CPUs and to allay any fears, I have another example. I have just read the temperatures of my notebook:
So if its 20 degree at my desk and my cpu is now 70 degree… At 60 degree my cpu will rise by 40 degree so my cpu will be 110 degree?
yes, at an ambient temperature of 60 degrees, the CPU temperature will also be just below the shutdown limit.
Note 1:
The CPU is lying flat on the table? That is actually not a permissible mounting direction. The air cannot circulate.
The control cabinet temperature is also important if the control system has not yet switched off because the service life can then no longer be guaranteed. This also applies to the housing plastic.
In summary:
If you want to do absolutely the right thing, you have to monitor the control cabinet temperature and check the installation position of the X20 components.
Do you need a quick, cheap solution? Look at the CPU temperature in a control cabinet at 50 degrees and use this temperature as a limit for the warning.