Tempo is expressed in BPM and can be set in two different ways :
You can enter any numerical value between 1 and 999. If you enter a non-numerical value, or a value outside this range, BPM jumps back to the last valid value or to the default (60 BPM) if none has been set yet.
This will increase or descrease the value by integer steps and automatically recompute delays and LFOs