Principle of Operation
The ASLD 2200 uses a Suspended Solids sensor to detect the density of the sludge; the
instrument moves the sensor to a point that is just above the interface. The motor is then used to
keep the sensor in that position when the interface moves.
The user is provided with information about the sensor reading by the panel of LED’s on the
circuit board.
The output of the sensor is divided as shown in the graph below:
The ‘motor’ LED’s will come on once the related sensor LED has been on for 5 seconds and
the motor will activate.
The ‘limits’ LED’s will be used when the system reaches either 0 or 100%
The 3 digit LED display will indicate the position of the sludge blanket as a percentage of the
depth of the tank. For example if the tank is 4 metres deep and the display is showing 25%, the
sludge blanket is 1 metre from the bottom of the tank.
Controls and Settings
Page 4
hi
gh
up
top
se
ns
or
m
ot
or
lim
its
low
dow
n
bot
tom
Suspended Solids
Sensor
Output
Both
LED’s OFF
Sensor high LED
ON
Sensor Low
LED ON
