About 5 seconds after selecting a Menu item and if there is no step A or B,
then the unit will automatically start to execute the menu item. In this case, the
red LED goes on continuously. In the first four Menu Points learning should be
initiated by step A. Blinking of the green LED indicates measurement during
learning. On getting a valid echo the yellow LED will light up and the relevant
numeric value of the measured distance appears on the output (for instance
with measured distance of 0.4 m the output will be 0.4 mA or 0.4 V!) With
repeated step A a new distance can be learnt and the old one will be
overwritten. Step B will finalise learning and result in return to the Menu item
selection. Another Step B will make the device quit Programming Mode
Parameters a and k can be programmed using Steps A and B in Menu item
4 and 5