Siemens SIMATIC Manual page 259

Wiring 2-wire loads to the voltage output of non-isolated module
Wire the loads to the Q
Interconnect terminal S+ to Q
A 2-wire circuit does not provide for compensation of line impedance.
Figure 4-18
See also
Wiring and connecting loads/actuators to analog outputs (Page 257)
S7-300 Module data
Manual, 06/2017, A5E00105505-AJ
4.7 Wiring and connecting loads/actuators to analog outputs
terminals and to the reference point of measuring circuit M
V
with terminal S to M
V
2-wire connection of loads to the voltage output of a non-isolated analog module
Principles of analog value processing
in the front connector.
ANA
.
ANA
259