ABB AC500 V3 - Connection of resistance thermometers in 3-wire configuration to the analog inputs

Fig. 139: Connection of resistance thermometers in 2-wire configuration to the analog inputs
The following measuring ranges can be configured Ä Chapter 1.7.4.1.7 “Parameterization”
on page 749 and Ä Chapter 1.7.4.1.9 “Measuring ranges” on page 761:
Pt100 -50 °C...+70 °C 2-wire configuration, 1
channel used
Pt100 -50 °C...+400 °C 2-wire configuration, 1
channel used
Pt1000 -50 °C...+400 °C 2-wire configuration, 1
channel used
Ni1000 -50 °C...+150 °C 2-wire configuration, 1
channel used
The function of the LEDs is described under Diagnosis and displays / Displays Ä Chapter
1.7.4.1.8 “Diagnosis and state LEDs” on page 755.
The module CI521-MODTCP performs a linearization of the resistance characteristic.
To avoid error messages from unused analog input channels, configure them as "unused".
Connection of resistance thermometers in 3-wire configuration to the analog inputs
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 CI521-
MODTCP provides a constant current source which is multiplexed over the max. 4 analog input
channels.
The following figure shows the connection of resistance thermometers in 3-wire configuration to
the analog inputs AI0 and AI1. Proceed with the analog inputs AI2 and AI3 in the same way.
Device specifications
Communication interface modules (S500) > Modbus
2022/01/313ADR010278, 3, en_US738