This part of IEC 60747 provides a guideline of indication of specifications of a low-power sensor being a device or a module allowing autonomous power supply operation, which contributes to the low-power design of a smart sensing unit. Here, the smart sensing unit comprises a smart sensor, a terminal module, and a power supply, which can send output data of the smart sensor to the outside. This part also provides a guideline of indication of specifications of the power supply to drive the smart sensor(s) in the smart sensing unit. Based on these, the three components of the smart sensing unit can be easily selected and combined from the point-of-view of newly designed, low-power, smart sensing units.