SandAlert Lite 2
nd
Edition
Page
20
Select Low(1.5), medium(2) or high(3.5) dependant on flow noise, fine tuning is achieved by typing
a value that is not set by the buttons. These values have no affect unless the threshold is set to
automatic. Increasing the value causes the threshold to move higher in response to the back ground
noise. See the earlier section on Sand impacts to see how the level should be set. After changing
these values have a look at the Real signal page for the well head that has been changed and ensure
that the threeshold is not too high or too low. If it is too high there will be no crossings and if too
low all the signal will be above the threshold.
The Threshold offset works in conjunction with Flow Noise to allow fine tuning when a difficult
application is encountered. The Threshold adds the value set (in mV) to the calculated auto
threshold. The reason is that if you increase the Flow noise figure to raise the threshold in quiet
conditions then when the noise increase the threshold will rise too high. Using Threshold offset
instead will allow an offset to be added that is not dependent on the current signal.
Suggested figures are:
Condition
Flow Noise
Threshold offset
Low Noise
1
200
Normal 2
300
High Noise
3.5
500
(High Noise is for extreme conditions, view sensor output screen after changing any of these
settings prior to finalising settings)
U and D are to change the Y-axis scale (U =up and D =down).
STOP RUN, will stop the unit from monitoring, this button is not normally used. When the unit is
re-booted monitoring is restarted automatically.
