Chapter 4 _________________________________________________________________ Operation
VAISALA _______________________________________________________________________ 119
- Log group name usually consists of a letter followed by a number.
Everything that MAWS can measure and calculate, it can also log in
its Flash memory. Approximate log memory capacity can be
calculated with the following equation:
m
f
c =
where
c = log memory capacity
f = 1 769 472 (capacity of an empty Flash memory)
m=
690 + e × (7 × p + 14) + (5 × p + 4) = memory consumed in
24 hours
e = number of logging events in one day (24 h)
p = number of logging parameters.
Example:
MAWS logs 10 parameters per minute.
e = 60 × 24 = 1440
m = 690 + 1440 × (7 × 10 + 14) + (5 × 10 + 4) = 121 704
c = 1 769 472 / 121 704 ≈ 14.5 days ≈ 2 weeks
The approximate maximum logging period for a setup where 10
measured values are logged is shown in Table 22 below.
Table 22 Log Memory Capacity
Logging Interval Maximum Logging Period
1 second 5 hours
10 seconds over 2 days
1 minute 2 weeks
10 minutes over 4 months
1 hour Almost 2 years
Log files are automatically deleted after a given period so that there is
always a certain amount of logged data saved in the Flash memory.
The period is adjustable in a setup and can vary from 0 (= at midnight,
the previous day's file will be deleted to free up memory) to never
delete (=log memory will be filled up completely. To ensure some
data backup, a value of for example 4 days may be feasible. If the
delete interval is set negative with the MAWS Lizard setup software,
the old log files will not be deleted automatically.
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