GESTRA NRG 21-11 Instructions De Montage page 8

English
Chart 1
Fluid: water, electrical conductivity
≥ 20 µS/cm at 25 °C.
Chart 2
Fluid: water, electrical conductivity
≥ 0.5 µS/cm at 25 °C,
relative dielectric constant Σ
Chart 3
Fluid: light fuel oil (EL), relative dielectric
constant constant Σ
If a fluid other than water or light fuel oil
(EL) is to be monitored, the position of the
code switches has to be determined by
measuring the voltage. Proceed as follows:
Fill vessel to required max. level, and
connect a voltmeter between terminals
"1" (+) and ⊥ (–), (fig. 8). Set all switches
to position " " (fig. 7). Now set each
OFF
individual switch in turn to "
switch 1, then switch 2, switch 3, switch 4,
switches 4 + 5 and switches 4 + 5 + 6.
When setting one switch and, as a result,
the value measured by the voltmeter
exceeds 7 V, undo the last switch position
setting.
After having set the code switch, replace
lid and fasten terminal box
screw on probe body.
E
Performance Tests
I
The supply voltage of the level probe
can be measured between terminals "3"
and "⊥" in the terminal box
The voltage should be 12 V d.c. If not,
the probe has to be checked at our
works or by a works official.
I
The level-proportional voltage U
be measured between terminals "1" (+)
and "⊥" (–). Raise level in vessel to the
maximum value of the utilized
measuring range (e. g. 1000 mm), and
measure voltage. Compare the value
measured with the value of the
corresponding chart (in chart 1 U
1000 mm is 4.6 V). The following values
have to be obtained in any case:
Level probe completely exposed:
≥ 0 V
U
M
Level probe completely submerged:
≤ 7 V
U
M
8
= 80.
R
= 2.3.
R
": first
ON
with
D
(fig. 4).
D
can
M
for
M
If with the probe rod submerged
U = 0 V or U > 7 V is measured, the
M M
probe has to be checked at our works
or by a works official.
Key to Fig. 1 + 2
Terminal box
D
PG 11 max. 60°
F
Body A. F. 55 mm, screwed 1½" to
1
DIN 228
Thermal insulation
2
Ring joint 98 x 55, DIN 7603
3
Plastic covered steel rope
4
H = Control range
5
L = Max. length of installation
6
Linear extension of plastic tubing
7
Weight
8
Tapped M6
9