Resistance And Rtd Measurement, Connections; 4-Wire System - BEAMEX MC5-IS User Manual

Resistance and RTD Measurement, Connections

4-wire System

MC5-IS sources current through the resis-
tor from the two left side terminals. MC5-
IS measures the voltage drop across the
resistor from the two right side terminals.
The 4-wire method gives the resistance
between the terminals of the resistor, it is
insensitive to the resistance of the con-
nection wires.
T/C INT. RJ
T/C, Low V R, RTD R, RTD
T/C
WIRES
ONLY
meas/sim
SENSOR MEASURE & SIMULATE
The two main problems in resistance and RTD measurement are
the effects of wiring resistances and thermovoltages in the resis-
tance measurement circuit. If possible, use 4-wire connection to
eliminate the effect of wiring resistance. The special resistance
measurement sequence of MC5-IS eliminates the thermovoltages
of the resistance measurement circuit.
MC5-IS continuously checks the connection type during resistance
and RTD measurement. The found connection type is displayed
on the resistance or RTD measurement window.
4 w meas HART I
®
meas/sink
V, I ,
sink
V, , Com
3 w meas
Uo: 16 V
Io: 24 mA
Po: 145 mW
OUTPUT MEASURE
ET E Low V
Additional Information
3-wire System
MC5-IS sources current through the resis-
tor from the two left side terminals. MC5-
IS measures the voltage drop across the
entire current loop and across the low side
connection wire. If both left side connec-
tion wires are identical, MC5-IS can com-
pensate for the resistance of the connec-
tion wires.
T/C INT. RJ
T/C, Low V
T/C
WIRES
ONLY
SENSOR MEASURE & SIMULATE
4 w meas HART I
®
R, RTD R, RTD meas/sink
V, I ,
sink
V, , Com
meas/sim 3 w meas
Uo: 16 V
Io: 24 mA
Po: 145 mW
OUTPUT MEASURE
ET E Low V
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