Industrial Shields Raspberry PLC 19R+, Quick User Manual

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Rev. 8: 29-04-2021
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time is less that 20 seconds. To know more technical specs about this device, you can consult
the
Raspberry PI UPS and RTC Shield User Manual .
NOTE: Do not confuse this UPS with the UPS models of other brands, the behaviour is
different.
14.1.1 How to execute commands before the Power Off process
The UPS has its own configuration file rpishutdown and service rpishutdown-service. The
placement of both files can be consulted in the Raspberry Pi PLC OS configuration manual.
To execute specific commands before finishing the Power Off process, you must follow the
next steps:
•
Create this path inside the /etc folder:
•
Inside this folder, create a file called pre-poweroff:
The file type can be anyone you want (Bash Scripts, Python, C++, etc.) but the most important
thing is that it must be called
pre-poweroff without any extension (you must indicate the file
type with the corresponding Shebang ). The script execution time cannot surpass 6 seconds, as
it is the Raspberry’s Power Off period. Take into account that this code only can be things that
do not depend on the external power supply, like creating a file or things directly related with
the Raspberry. (Following this rule, you cannot do things such as enabling an output so it
depends on the external power supply).
•
Give the execution permissions to the file:
Following these steps, the file must be executed before the Raspberry Power Off.
sudo mkdir -p rpishutdown/hooks/
sudo nano pre-poweroff
sudo chmod ugo+x pre-poweroffs