Siemens SIMATIC S5 ET 200U - Page 196

7-4
ET 200U Distributed I/O Station
EWA 4NEB 812 6087–02b
Compen–
sating Box
13579
24 6 8
10
Reference
Junction
Thermal
Coupling
–
+
–
+
+–
Figure 7-1 Voltage Measuring with Isolated Thermocouples
(6ES5 464–8MA11/8MA21)
With non–floating sensors (e.g., non–isolated thermocouples) the permissible
potential difference V
CM
must not be exceeded (see maximum values of the
individual modules).
Compen–
sating Box
13579
24 6 810
Reference
Junction
Thermal
Coupling
–
+
–
+
+–
V
CM
Figure 7-2 Voltage Measuring with Non–Isolated Thermocouples
(6ES5 464–8MA11/8MA21)
Analog Value Processing