MULTICAL® 803
Kamstrup A/S · Technical description · 5512-2360_A1_GB_02.2019
115
2-wire sensor connection
The temperature sensor inputs of MULTICAL® 803 are designed with 4-wire sensor inputs. Therefore, when using 2-
wire sensor pairs, always mount the jumper as shown in
Figure 7
or short-circuit the right and left connection
terminals, respectively, in the 4-wire input, as shown in
Figure 8
For all 2-wire sensor connections, it applies that the cable length and cross section of the two sensors which are used
as temperature sensor pair for a heat or cooling meter must always be identical, and the delivered cable length must
neither be shortened nor extended.
The limitations connected to the use of 2-wire sensor pairs according to EN 1434-2 appear from the table below. In
addition, the table indicates how much error the longer 2-wire cables will cause.
Kamstrup delivers Pt500 sensor pairs with up to 10 m cable (2 x 0.25 mm
2
).
Figure 7
Figure 8
Cable cross
section
[
mm
2
]
Pt100 sensors
Pt500 sensors
Max cable length
[
m
]
Error
1
[
K/m
]
Max cable length
[
m
]
Error
1
[
K/m
]
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
Table 4
1
The error is calculated for copper cable at 20 °C. At higher cable temperatures, the error will be greater.
MULTICAL® 803 has a temperature sensor offset function that can be used to reduce the error display, which
originates from the cable resistance and zero error of the sensors. Read more about offset adjustment in paragraph
7.3.