You can use either the number of rack units or a descriptive text to describe the vertical locations (Z coordinates) of environmental sensors and actuators.
To determine the Z coordinate format:
Click the PDU folder.
Note: The PDU folder is named "my PX" by default. The name can be customized. See Naming the PDU.
Click Setup in the Settings section. The Pdu Setup dialog appears.
In the Peripheral Device Z Coordinate Format field, click the drop-down arrow and select an option from the list.
Rack Units: The height of the Z coordinate is measured in standard rack units. When this is selected, you can type a numeric value in the rack unit to describe the Z coordinate of any environmental sensors or actuators.
Free-Form: Any alphanumeric string can be used for specifying the Z coordinate.