MULTICAL® 803
Kamstrup A/S · Technical description · 5512-2360_A1_GB_02.2019
135
The limitations connected to the use of 2-wire sensor pairs according to EN 1434-2:2015 appear from the table
below.
Cable cross
section
[
mm
2
]
Pt100 sensors
Pt500 sensors
Max cable length
[
m
]
Subject to
EN 1434-2:2015
Temperature increase
[
K/m
]
Copper @ 20
°
C
Max cable length
[
m
]
Subject to
EN 1434-2:2015
Temperature increase
[
K/m
]
Copper @ 20
°
C
0.25
2.5
0.450
12.5
0.090
0.50
5.0
0.200
25.0
0.040
0.75
7.5
0.133
37.5
0.027
1.50
15.0
0.067
75.0
0.013
Table 5
4-wire sensor pair
For installations requiring longer cables than listed in the table above, it is recommended to use 4-wire sensor pairs.
By default, MULTICAL
803 is prepared for 4-wire connection on all temperature sensor inputs.
The 4-wire construction uses two conductors for measuring current and two conductors for measuring signal, which
means that the construction is in theory uninfluenced by long sensor cables. In practice, cables ought not to be
longer than 100 m and it is recommended to use 4 x 0.25 mm
2
.
The connection cable ought to have an outer diameter of 5-6 mm in order to obtain optimum tightness of both
MULTICAL
803 and the screw joint for the 4-wire sensor. The isolation material/cover of the cable ought to be
selected on the basis of the maximum temperature in the installation. PVC cables are normally used up to 80
°
C and
for higher temperatures, silicone cables are often used.
Note: When presetting the temperature value, it is important to insert jumpers in the connection terminals so that
the temperature sensor inputs with preset are changed to 2-wire connections. Read more about preset of the
temperature value in paragraph 7.13.