CB Watch 3 User Manual
v6.3 - May 2019
Page 42 of 100
HMI: Measurements/Alarms
Figure 57
–
Excessive moisture alarm
Short and long-term horizons
The rate of change of the pressure can be calculated using two sets of values:
•
values in the “short
-
term” stack measured every 10 minutes
•
values in the “long
-
term” stack
measured every day
These values are used to calculate a linear extrapolation/forecast of the pressure in the
future at the end of either the
“short
-
term” or “long
-
term”
time horizon.
Figure 58
–
Linear gas pressure extrapolation
•
Short-term extrapolated pressure at 20°C: future value computed using linear
regression and a history of 2.5x the short-term horizon
•
Long-term extrapolated pressure at 20°C: future value computed using linear
regression and a history of 2.5x the long-term horizon
Note: when there are not enough data points recorded to date to calculate the short or
long-term trend,
then the corresponding “stack
not enough
” alarm
flag is set to indicate
that the value in the register may not be accurate. The value is not displayed in the HMI
and is replaced by a “
-
“ instead.
The time horizons need to be defined first:
