Siemens Simatic S7-300 - Page 270

Analog Modules
4-64
Programmable Logic Controllers S7-300 Module Data
A5E00105505-03
Connecting thermocouples with temperature compensation to the
SM 331; AI 8 x TC
All 8 inputs are available as measurement channels when the thermocouples are
connected via reference junctions that are controlled at 0 °C or 50 °C.
Backplane
bus
ADUs
L+
M
K7
K0
M+
M-
M+
M-
M+
M-
Copper
wire
Reference junction
controlled at
0C or 50C
K6
.
.
.
Logic
Figure 4-26 Connecting thermocouples via a reference junction to the
SM 331; AI 8 x TC