Connecting A Two-Wire Sensor To The Logo! Am 2; Logo! Am 2 Pt100 - Siemens Logo! Manual

LOGO! installation and wiring

Connecting a two-wire sensor to the LOGO! AM 2

Wire up the two-wire sensor's connecting wires as follows:
1. Connect the minus connector on the sensor to connec-
tor I1 on the analog expansion module.
2. Connect the plus connector on the sensor to the 24 V
supply voltage (L+).
3. Connect the ground connector of the supply voltage to
connector M1 on the analog expansion module.

LOGO! AM 2 PT100

You can connect either a 2- or 3-wire Pt100 resistive
thermocouple to the module.
For a 2-wire connection, you need to short-circuit terminals
M1+ and IC1 or M2+ and IC2. Errors caused by the ohmic
resistance of the measuring line are not compensated with
this type of connection. A line resistance of 1 W is
proportional to a measuring error of +2.5 °C.
A 3-wire technique suppresses the influence of the cable
length (ohmic resistance) on the result of the
measurement.
2-wire technique
L+ M
PE
M1+
38
L+ M
RUN/
STOP
IC1 M1- M2+ IC2 M2-
Pt100
3-wire technique
L+ M L+ M
RUN/
STOP
PE
M1+ IC1 M1- M2+ IC2 M2-
Pt100
LOGO! Manual
A5E00380835-01