EN
Manual XC250
9
Alarm function
In IR DP mode the alarm function is activated automatically. Alarm
triggering and intensity are defined by the upper and lower alarm
threshold.
These two limit values can be calculated from the measured dew
point temperature (TdP) and the threshold values individually
determined in configuration mode: upper threshold (Hi) and lower
threshold (Lo).
The sum of dew point temperature and upper threshold value (Hi)
constitutes the upper alarm limit value (TdP + Hi).
The difference of dew point temperature (TdP) and lower
threshold value (Lo) constitutes the lower alarm limit
value (TdP - Lo).
If the surface temperature falls below the upper alarm
limit (TdP + Hi) an acoustic and visual alarm (flashing laser and
flashing ALARM display) is triggered which intensifies in
proportion to the increased approximation to lower alarm limit.
The more the surface temperature drops, the faster increases the
repetition frequency of the acoustic and visual signals. Maximum
repetition frequency is triggered when reaching the lower alarm
limit (TdP - Lo).
Example:
The current dew point temperature (TdP) is +10 °C.
You define the upper threshold (Hi) as 5 °C and lower
threshold (Lo) as 5 °C. Then the alarm starts at +15 °C (TdP + Hi)
and reaches maximum intensity at 5 °C (TdP - Lo).
Temperature display configuration
The temperature can be displayed in either Celsius (°C) or
Fahrenheit (°F).
The temperature can be displayed as air temperature or surface
temperature.
1. Press the Up key (9) to switch between °C and °F in the
respective operating modes.
– The temperature will be displayed in the selected unit in the
upper measured value display (16).
– The unit (17) will be indicated on the display (1).
Operating
mode
Temperature unit
Description
TH
°C
Air temperature in °C
°F
Air temperature in °F
IR
°C
Surface temperature in °C
°F
Surface temperature in °F
IR DP
°C
Surface temperature in °C
°F
Surface temperature in °F
%WT
CM
m/s
ppm °F °C
17