A typical power requirement is 5V/10mA or 24V/3mA – but this is at 100% duty cycle. Power usage can be reduced (e.g. for extending battery life) by the use of a sleep cycle – thus reducing the effective duty cycle.
A sleep cycle can be implemented by, for example, using an algorithm which measures displacement once every 10 seconds (equivalent to a 0,1% duty cycle) and reverting to 100% duty cycle should the displacement have changed. In turn, the sensors can then revert to sleep mode if the displacement does not change again for a period of say, 10 seconds.