def getActorLimits(self):
        """ Returns a list of 2-tuples, e.g. [(-3.14, 3.14), (-0.001, 0.001)],
        one tuple per parameter, giving min and max for that parameter.
        """
        generators = [g for g in self.env.case.online_generators
                      if g.bus.type != REFERENCE]
        limits = []
        for g in generators:
            limits.append((g.p_min, g.p_max))

        logger.info("Actor limits: %s" % limits)

        return limits