Hach Sigma 950, Instrument Manual

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Programming Features
If a one-minute logging interval is selected in power save mode, a reading will be taken
once per minute, at which time that reading is logged.
If a five-minute logging interval is selected, readings are taken every minute but the data
is not logged until the five minute logging interval ends. At the time the readings are
averaged over the previous five minutes; that average is logged.
Note: The Review All Items selection from the Setup menu indicates the maximum available logging
hours for the channels and recording intervals you selected. The flow meter calculates this
information when the program is run using the
RUN/STOP
key.
Continuous Mode
When a one-minute logging interval is selected, a reading will be taken approximately
every second but data is not logged until the logging interval ends. At that time, the
readings are averaged over the logging interval; that average is logged.
When a five-minute logging interval is selected, readings are still taken every second but
the data is not logged until the five-minute logging interval ends. At that time, the readings
are averaged over the previous five minutes; that average is logged.
Longer logging intervals result in a longer total recording time. Lower resolution also
occurs since more averaging is done at higher logging intervals. Choose the shortest
logging interval possible, while still making data collection convenient. Pick a logging
interval that almost fills memory over the course of one month if data will be collected
monthly.
B.13 Data Logging Memory Allocation Options
The Sigma 950 Flow Meter uses a management scheme called “Dynamic Memory
Allocation.” All readings are logged in battery-backed Random Access Memory (RAM).
RAM memory is allocated to each channel dynamically during operation. If one channel is
logging at 5-minute intervals and a second channel is logging at 1-minute intervals, the
meter automatically configures memory so that both channels fill memory at the same
time. Five times as much memory is assigned to the channel that is logging at 1-minute
intervals than the channel that is logging at 5-minute intervals.
Table 36 Logging Intervals vs. Total Recording Time for Each Memory Configuration
1
Logging Interval
With 128K Bytes of RAM
(Standard)
(approx. 17,280 readings)
With 512K Bytes of RAM
(Optional)
(approx. 115,630 readings)
Total recording time (days) before memory is full
1 12 80
2 24 160
3 36 240
5 60 401
6 72 481
10 120 803
12 144 963
15 180 1204
20 240 1606
30 360 2409
60 720 4818
1
Assuming one logged channel.