60
1MRS750915-MUM
Machine Terminal
Technical Reference Manual, General
REM 54_
Current transducers
When a current transducer is connected to the RTD/analog input, the SHUNT and
IN+ terminals are linked together as are the GND and IN- terminals. The incoming
current signal is connected to the IN+ terminal and the outgoing current signal to the
IN- terminal.
currtran_b
Fig. 5.1.9.6.-2 Principle diagram for the connection of current transducers
Voltage transducers
When a voltage transducer is connected to the RTD/analog input, the GND and IN-
terminals are linked together. The incoming voltage signal is connected to the IN+
terminal and the return voltage signal lead to the IN- terminal.
volttran_b
Fig. 5.1.9.6.-3 Principle diagram for the connection of voltage transducers
*) The GND terminals are galvanically isolated from the supply and enclosure of the
machine terminal, but they are all connected to each other, i.e. they share the same
potential. When several inputs are connected to single-ended signal sources that
share a common ground, ground loops result if the connection GND <-> IN- is done
on every input. In this situation, the connection GND <-> IN- is done on only one of
the concerned RTD/analog inputs.
Resistance sensors
The resistance sensors may be connected to the RTD/analog input according to
either the three-wire or the two-wire connection principle. With the three-wire
measuring principle, the wire resistance is automatically compensated. The resistor,
or RTD sensor, is connected across the IN+ and IN- inputs, and the - side of the
resistor/RTD sensor is connected to the GND input. The leads connected to the IN+
and GND inputs must be of the same type.
SHUNT
IN -
GND
I
*)
IN +
G
mA
DIFF
+
-
Transducer
amplifier
ensor
SHUNT
IN -
GND
*)
IN +
G
mA
DIFF
+
-
Transducer
am p lifier
r
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