restarting the PID from an interrupt

[brianjmurrell]

Am I understanding correctly that if I needed to interrupt the PID and wanted to resume it from where it left off, I would need to save the:

        self._proportional = 0
        self._integral = 0
        self._derivative = 0

values and then set them when starting it back up again? Would I also need to do something with:

        self._last_time = _current_time()
        self._last_output = None
        self._last_input = None

It might be nice to have save() and load() methods to automate this.

[m-lundberg]

Hello, sorry for the slow response.

As long as you keep the same PID-object, self._proportional etc. will be kept so you don't need to save them. However, if you go a long time without updating the PID you will have a very large time delta the next time you call it which would lead to some weird values in the beginning. You could set

pid._last_time = PID._current_time()

before starting again and it should work OK.

[m-lundberg]

The way I see it, save() and load() methods would be unnecessary so I'm closing this. Feel free to reopen if you disagree!