Manual

IN-E-HL-NT-V2_12
Rotronic AG
Bassersdorf, Switzerland
Document code
Unit
HygroLog HL-NT data logger:
instruction manual
Instruction Manual
Document Type
Page
12 of 48
Document title
© 2009-2012; Rotronic AG IN-E-HL-NT-V2_12
● Measured values and computed parameter, or any parameter combination
● User custom text (used for the log file header)
● User name, HW4-ID, HW4 Serial Number
● Automatic creation of a new file after 200,000 data points or at the end of each day, week or
month
Note: unlimited logging (loop mode logging) is not possible. Logging stops automatically when the
flash memory card is full. Prior to logging, the user may use HW4 to check the amount of free
memory, and verify that there is enough room available.
If the flash memory card is removed when logging is active, the HygroLog HL-NT will stop logging
until a new card is inserted. Unless the stop date and time have been reached, logging will start
again under the next available file name when a new card is inserted.
Warning: removing the memory card while logging is active may result in a corrupted log file and
in loss of data.
Logging can be started immediately for any individual input from the keypad of the HygroLog HL-
NT. A deferred start can only be programmed with the HW4 software. The green LED of the
HygroLog HL-NT can be set to flash when the instrument is recording data. To conserve battery
power, you may want to do this only when an external power source is being used.
Logging can be immediately stopped for any individual input directly from the keypad. With HW4,
logging can be stopped either immediately or at a future date and time for any individual input or
for all inputs.
When logging is ended, the HygroLog HL-NT returns to the measuring mode.
2.8.3 Trend indicators
See also: Main operating modes and measurement interval
When the trend indicator function is enabled, a symbol appears on the left side of the LC display,
on the line corresponding to each measured or calculated value. An up arrow denotes a rising
value and a down arrow denotes a decreasing value. Both arrows denote a stable value.
The trend of a parameter is evaluated by comparing successive averages made of 6 values each.
With the shortest possible measurement interval of 5 seconds, each average covers a time period
of 30 seconds and the first indication of a trend is available after one minute. Subsequently, the
trend is evaluated and updated every 30 seconds. With a longer measurement interval, each
average is computed over a longer period of time (always using 6 values) and the trend is also
updated over longer intervals of time.
For any measured or calculated parameter, the trend indicator shows a stable condition when the
absolute value of the difference between two successive averages is < 0.02.
2.8.4 Alarm function
Using the HW4 software, both a high and a low alarm value can be associated with the humidity,
temperature and calculated parameter of each probe input, A hysteresis value can also be
entered for each parameter. This value is used for both the low and the high alarm conditions.