Phoenix Contact RAD-RS485-IFS User Manual

RAD-...-IFS
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PHOENIX CONTACT 105542_en_05
7.2.1 Connecting sensors
You can connect 2-wire or 3-wire sensors to the extension module. Take the measuring
errors of the different measuring methods into consideration.
2-wire connection technology
2-wire connection technology is the most cost-effective connection technology. The tem-
perature-related voltage is not directly measured at the sensor and is therefore falsified by
the two cable resistances R
L
. The measuring errors that occur may render the entire mea-
surement useless. Please observe the diagrams in Section “Measuring errors when using
2-wire connection technology” on page 93.
For 2-wire connection technology, an insertion bridge is required between terminal blocks
x.2 and x.3.
Figure 7-5 2-wire connection technology
3-wire connection technology
With 3-wire connection technology, the temperature-related voltage is measured several
times. Corresponding calculations additionally reduce the effect of the cable resistance on
the measurement result. The results are almost as good as those achieved with 4-wire
connection technology.
The cable resistances R
L
at terminal blocks +I and -I must have the same value. This allows
you to subtract the measured cable resistance from the measurement result and to get the
Pt100 platinum resistance value.
Figure 7-6 3-wire connection technology
µC
2.1
2.2
2.3
3.1
3.2
3.3
5.1
5.2
5.3
4.1
4.2
4.3
IO-MAP
0
1
DC
DC
IFS
IFS
A
D
1mA
A
D
1mA
A
D
1mA
A
D
1mA
-I2
-U2
+I2
+I1
-U1
-I1
+I3
-U3
-I3
+I4
-U4
-I4
RL
RL
I+
I–
RTD
ϑ
µC
2.1
2.2
2.3
3.1
3.2
3.3
5.1
5.2
5.3
4.1
4.2
4.3
IO-MAP
0
1
DC
DC
IFS
IFS
A
D
1mA
A
D
1mA
A
D
1mA
A
D
1mA
-I2
-U2
+I2
+I1
-U1
-I1
+I3
-U3
-I3
+I4
-U4
-I4
RL
I+
RTD
ϑ
RL
I–
U–

Phoenix Contact RAD-RS485-IFS Specifications

General

Brand	Phoenix Contact
Model	RAD-RS485-IFS
Category	Transceiver
Language	English