In this example, when the sludge interface level rises to 1.95 m, relay 1 will come
on until the level drops to 1.85 m when it will turn off.
The display for point 1 will show the sludge interface level in the tank.
The mA output will be representative of sludge interface level where 4mA = empty
level (0%) and 20mA = 2.3m (100%).