IDL 101
FUNCTIONAL DESCRIPTION
40
HB_IDL101_E_V222.doc
Gantner Instruments Test & Measurement GmbH
Notice
: The
Datalogger IDL 101 supports resistance measuring in 2 and 4-wire technique. With resistance measuring
in 2-wire technique the supply lines cause an additional fall of potential, thus distorting the measuring result and
influencing the measuring accuracy. Therefore it is necessary to pay attention specially with resistance measuring in 2-
wire-technique to use as low-impedance leads as possible to the sensors and to make sure that the leads are well-
connected with the data logger and the sensor. With resistance measuring in 4-wire technique the fall of potential is
picked up directly at the sensor, so that the measuring results are not influenced by the supply lines any longer.
Notice:
Measuring by a resistance bridge is possible with an external power supply only as the output impedance of
the source terminal is to high.
Measurement of Temperature with Thermocouples:
Figure 6.6 Measurement of temperature with internal cold junction
compensation by the terminal clamp ICJ 104
Figure 6.7 Measurement of temperature with external
cold junction compensation
S
O
U
R
C
E
A
In
+
A
In
-
S
O
U
R
C
E
A
In
+
A
In
-
A
GN
D
A
GN
D
1
2
Connection Scheme
Circuit
ϑ
ϑ
= Lin (U + Lin )
1
-1
K
ϑ
K
2
= Lin' (U )
ICJ 104
1 M
Ω
R
0
SOURCE
AIn +
AIn -
A
GND
U
1
U
2
U
+
-
ϑ
ϑ
K
ϑ
S
O
U
R
C
E
A
In
+
A
In
-
S
O
U
R
C
E
A
In
+
A
In
-
A
GN
D
A
GN
D
1
2
Connection Scheme
Circuit
ϑ
ϑ
= Lin (U + Lin )
1
-1
r
1 M
Ω
1 M
Ω
SOURCE
AIn +
AIn -
A
GND
U
1
ϑ
ϑ
r
ϑ
ϑ
r