ABB AC500 PLC - Connection of Resistance Thermometers in 3-wire Configuration

UP
ZP
1.0
I0-
1.1
I1-
1.8
UP
1.9
ZP
PTC
2.0
I0+
2.1
I1+
2.8
UP
2.9
ZP
Pt100
Pt1000
Ni1000
Fig. 33: Connection example
The following measuring ranges can be configured Ä Chapter 1.5.2.2.1.6 “Parameterization”
on page 463.
Pt100 -50 °C...+70 °C 2-wire configuration, one
channel used
Pt100 -50 °C...+400 °C 2-wire configuration, one
channel used
Pt1000 -50 °C...+400 °C 2-wire configuration, one
channel used
Ni1000 -50 °C...+150 °C 2-wire configuration, one
channel used
The function of the LEDs is described under Displays Ä Chapter 1.5.2.2.1.7 “Diagnosis”
on page 466.
The module AI523 performs a linearization of the resistance characteristic.
In order to avoid error messages from unused analog input channels, it is useful to configure
them as "unused".
Connection of Resistance Thermometers in 3-wire Configuration
When resistance thermometers (Pt100, Pt1000, Ni1000) are used, a constant current must flow
through them to build the necessary voltage drop for the evaluation. For this, the module AI523
provides a constant current source which is multiplexed over the max. 8 (depending on the con-
figuration) analog channels.
Device Specifications
I/O Modules > Analog I/O Modules
2019/04/173ADR010121, 13, en_US456