levr
LIM-05 user manual
Dated 25/5/2017
http://www.levr.pl/
Page
13
of
20
If the LIM-05 instrument is unable to automatically “locate” the end of the wire for
any reason, conduct the calibration described in section 0 of this manual.
METHOD 2
The specific procedure is described in section 8.1.
Note: A new reference run should be created and recorded after changing the physical
length of the sensor wire. (See section 6.4 i 0).
6.2 “Napi
ę
cie progowe Up=” (Voltage threshold Up=) entry
Input signals whose voltage amplitude is within the ±Up range are not analysed. This
limitation can be used to eliminate some of the low-amplitude interference appearing
in the alarm system of the district heating pipeline. The ±Up voltage range can be set
separately for each measurement channel.
6.3 “Liczba kanałów=” (Number of channels =) entry
The instrument can monitor up to four sensor loops. The entered number (1–4)
specifies the number of monitored sections of the district heating pipeline with the
alarm system. (See section 0). If the number of connected loops is smaller, they have
to be connected to subsequent measurement ports of the instrument starting from the
outermost left port (channel 1).
6.4 “Przebieg odniesienia” (Reference run) entry
Activating this function will force a specific measurement cycle in the selected
measurement channel. The instrument will calculate the average value of measured
results i, which will be recorded as the reference run. (See section 0).
6.5 “Czas martwy=” (Dead time=) entry
The automatic measurement cycle of the fault locator consists of measurements carried
out for every section of the district heating pipeline. The measurements are carried out
sequentially. Between the measurement cycles, there is a gap referred to as the dead
time. The dead time can be adjusted in the range of 1–255 min. (See section 0).
6.6 “VOP=” entry
This entry enables setting the VOP coefficient for all measurement channels in use. It
may be a fraction in the range of 0.3–1.0 or a value expressed as percentage from 30 to
100%. (See section 0).
The factory setting is: VOP = 0.92. In practice, the coefficient is set as 0.84–0.93 for
measurements of district heating pipelines.
6.7 “Parametry impulsu>” (Pulse parameters>) entry
The amplitude in [V] and duration in [ns] of the measurement pulse can be set for
every measurement channel. Both of these values are selected depending on the length
of the monitored district heating pipeline (length of the monitored sensor wire).
“1-czas trwania =” (1 – duration =) – duration of the measurement pulse is changed
with keys marked with “
▲
” (increase) and “
▼
”(decrease) symbols. The changes are
implemented in a stepwise fashion, at 12.5-ns intervals within a range of 12.5–75 ns.
“2-amplituda impulsu =” (2 – pulse amplitude) – the amplitude of the measurement
pulse can be changed within a range of 2.3–7.8 V (4.8–14.6 V for amplitude of the
voltage of the measurement pulse generator) using keys marked with “
▲
” (increase)
and “
▼
”(decrease) symbols.
