GUILCOR AR004926, Инструкция по эксплуатации, Страница: 49 / 75

49
How to set a variable alarm limit _____________________
In some applications, you need the alarm limit to depend on another
measured value.
Example: we require that the alarm must be activated when internal
temperature T
int
becomes by 3
°C higher than exterior
temperature T
ext
. In this case add another calculated
quantity that will be the difference of both measured
temperatures T
int
- T
ext
. The alarm limit for this quantity
shall be 3
°C. The alarm then occurs if (T
int
- T
ext
) > 3
°C.
Selftest error ____________________________________
The selftest is used for monitoring the state of the batteries. If the
Multilogger reports this error, the batteries are empty. You can check
the battery status in the System information menu or in the
software
Vision on the Device home page. If the battery voltage
drops under 3.45 V, the Multilogger reports a self-test error. A drop
of the power supply voltage is also indicated by the given symbol
on the device status line. The batteries have to be recharged
or replaced.
Measurement accuracy problems ____________________
In a majority of cases, incorrectly measured temperature and relative
humidity values are caused by an incorrect position of the probes or
measuring method. Some comments related to this topic are shown
in the next Chapter,
Operation and maintenance recommendations .
When measuring room temperature and/or relative humidity using a
short probe without a cable and with permanently active Ethernet
interface, measurement accuracy can slightly worsen due to the
waste heat generated in the device. It especially problem of stationary
installations on the wall with insufficient air flow.
When measuring temperature using thermocouples, you have to
make sure that neither the measuring ends, nor conductors are
connected to any conductive parts that may cause unwanted
couplings. This may, in exceptional cases even cause damage the
device.