Hach 900 MAX - Manual (Page 121)

Appendix B
Page 119
8990apdx_pfeatures.fm Programming Features
Data Log
From the Main Menu, select SETUP > ADVANCED OPTIONS > DATALOG.
The sampler can record up to 116,000 readings from any or all input channels
and store them in solid state, battery-backed memory for later viewing or
retrieval.
This option allows the selection of channels to log, how often to log, and how
to treat the memory when it becomes full (Slate or Wrap).
The sampler has two data logging modes:
• Power Save Mode
• Continuous Mode
Logging Intervals
Logging Intervals are designed to optimize the available memory so that
readings can be logged for a longer period of time. A logging interval is the
time period over which readings are taken and then averaged.
Power Save Mode
Power Save Mode is automatically initiated upon power-up if a battery is
installed on the sampler. When operating in Power Save Mode, the sampler
microprocessor spends most of its time asleep conserving battery power.
Once per minute, the sampler wakes up, logs the readings from all enabled
input channels, performs any other necessary functions and then goes back
to sleep.
Selecting a five-minute logging interval means that the readings are still taken
every minute but the data is not logged until the five-minute logging interval is
complete. At that time the readings are averaged over the previous five
minutes and that average is logged
Continuous Mode
Continuous Mode is automatically initiated upon power up if ac power is
supplied. The microprocessor stays awake at all times taking readings every
second. At the end of the specified logging interval, the readings are averaged
over the previous interval and stored in memory. If a one-minute logging
interval is selected, a reading will be taken approximately every second but no
data is logged until the logging interval ends. At that time, the readings are
averaged over the logging interval and only the average is logged.
If a five-minute logging interval is selected, readings are still taken every
second but the data are not logged until the five-minute logging interval ends.
At that time, the readings are averaged over the previous five minutes and the
average is logged.
Extended Power Mode
Extended Power Mode provides additional battery life by keeping a sampler
powered down during the entire logging interval. For example, if a logging
interval of five minutes is selected, the sampler stays asleep until the five
minutes has expired. It then wakes up, takes a reading, logs it in memory and
goes back to sleep for another five minutes. The sampler does not wake up
every minute as it does in normal