ABB AC500 V3 Hardware Manual page 528

Device specifications
I/O modules > Analog I/O modules
Fig. 62: 8 analog inputs and 8 analog outputs, individually configurable
"Functionality" on page 524
Connection of resistance thermometers in 2-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 I/O module
provides a constant current source which is multiplexed over the 8 analog channels.
528
CAUTION!
By installing equipotential bonding conductors between the different parts of the
system, it must be ensured that the potential difference between ZP and AGND
never can exceed 1 V.
CAUTION!
The process supply voltage must be included in the grounding concept (e. g.
grounding of the negative pole).
3ADR010278, 3, en_US
Ä Chapter 1.6.2.2.6.2
2022/01/31