ABB AC500 V3 Hardware Manual page 632

Device specifications
Communication interface modules (S500) > CANopen
Pt100
Pt1000
Ni1000
For the measuring ranges that can be configured, please refer to sections Measuring Ranges
Ä Chapter 1.7.2.2.10 "Measuring ranges" on page 650 and Parameterization Ä Chapter
1.7.2.2.7 "Parameterization" on page 640.
The module CI581-CN performs a linearization of the resistance characteristic.
To avoid error messages, configure unused analog input channels 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
CI581-CN 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.
Fig. 104: Connection of resistance thermometers in 3-wire configuration to the analog inputs
With 3-wire configuration, 2 adjacent analog channels belong together (e. g. the channels 0 and
1). In this case, both channels are configured according to the desired operating mode. The
lower address must be the even address (channel 0), the next higher address must be the odd
address (channel 1).
The constant current of one channel flows through the resistance thermometer. The constant
current of the other channel flows through one of the cores. The module calculates the meas-
ured value from the two voltage drops and stores it under the input with the higher channel
number (e. g. I1).
In order to keep measuring errors as small as possible, it is necessary to have all the involved
conductors in the same cable. All the conductors must have the same cross section.
632
Pt100
Pt1000
Ni1000
+
24 V DC
-
3ADR010278, 3, en_US
2-wire configuration, 1 channel used
2-wire configuration, 1 channel used
2-wire configuration, 1 channel used
2.0
AI0+
2.1
AI1+
2.2
AI2+
2.3
AI3+
2.4
AI-
2.5
AO0+
2.6
AO1+
2.7
AO-
2.8
UP
2.9
ZP
2022/01/31