In Sensor IQ the output number is the same as the slot number, or if the rack is fully populated with 1-pole relays, it equates to a relay. In normal orientation (with the UI at the bottom) the odd numbers are on the left side and even numbers are on the right side, with output 1 at the top-left, and output 48 at the bottom-right.
If the rack is inverted (with the UI at the top) the even numbers are on the left, and odd numbers are on the right, with output 1 at the bottom-right, and output 48 at the top-left.
DMX/sACN numbering always starts with output 1 and goes through output 48 regardless of rack orientation, unless you manually change the addressing of individual outputs. The same holds true for circuit numbering.