HIQUEL GmbH
Page 5
Author:
Peter Reiter
File:
HIQUEL_AppNote_TCL_1_E_R0100.doc
Translator: Markus Rindler
Date:
05.07.2004 12:56
Measuring range
The TCL has 2 switchable measuring ranges
(sensitivity). First measuring range is between 250
Ohm and 100kOhm (LOW), second is between
50kOhm and 1MOhm (HIGH). Through switch-
hysteresis, due to component tolerances and
specific peculiarities the measuring ranges are
only in a certain range reasonably usable.
Therefore we differ two different measuring
ranges. The adjustable measuring range and the
usable measuring range.
adjustable measuring range
usable measuring range
LOW
250Ohm … 100kOhm
1kOhm … 80kOhm
HIGH
50kOhm … 1MOhm
70kOhm … 800kOhm
The overlap of the measuring ranges is desired. It should also ease the adjustment of the
level control.
Set sensitivity
Place a special attention to the balance, as the impedance of the medium you want to
measure changes because of temperature, solved salts, pH-value, immersion depth of the
sensors, sensors itself and the receptacle.
The following calibration instructions allow a save and secure configuration of the level
controls. Other adjustments are conceivable and can be carried out by skilled engineers.
If the level control has a time delay (f.i. TCL3), you have to set it to a minimum during
calibration. Adjust it to the desired value after the settings.
Level control with one fill factor
Fill
Connect the level control completely and bring the sensor in position. Fill the receptacle in
such a way that the sensor is a little immersed (maximum fill factor).
Adjust front switch to: one level, filling, high sensitivity. Rotate potentiometer clockwise to the
stop. Relay (R) must not be active. Now turn the potentiometer slowly counter clockwise to
the left. If the left stop of the potentiometer is reached, turn it again clockwise until the right
stop is reached. Adjust front switch to “low sensitivity” and turn the potentiometer again
counter clockwise to the left. If the relay now switches automatically, the impedance of the
liquid has fallen below. Now you have to turn back the potentiometer half turn. If you reach
the right stop position before, switch back to „high sensitivity“ and execute the half turn to the
right there. The level control is now ready.
10
0
1.
00
0
10
.0
00
1
0
0.
00
0
80
.0
00
70
.0
00
1
.0
0
0.
00
0
8
0
0.
00
0
100
250
1.000
10.000
50.000
100.000
1.000.000
LOW
HIGH
ad
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usable measuring range