ABB AC500 PLC - Connection of Resistors in 2-wire Configuration; Connection of a Resistance Measuring Bridge with Internal Supply

Connection of Resistors in 2-wire Configuration
For evaluating resistors, a constant current must flow through them to build the necessary
voltage drop. For this, the module AI531 provides a constant current source which is multi-
plexed over the 4 analog channels.
1.0
I0-
1.1
I0B
1.8
UP
1.9
ZP
PTC
2.0
I0+
2.1
I0A
2.8
UP
2.9
ZP
ZP
UP
0 ... 50 kOhm
Fig. 54: Connection example
The following measuring ranges can be configured Ä Chapter 1.5.2.2.2.6 “Parameterization”
on page 489 :
Resistor 50 kΩ 1 channel used
For a description of the function of the LEDs, please refer to Diagnosis and displays / displays.
In order to avoid error messages from unused analog input channels, it is useful to configure
them as "unused".
Connection of a Resistance Measuring Bridge with Internal Supply
When resistance measuring bridges are connected, the short-circuit-proof voltage output
(internal supply) at pin I0A (or I2A, I4A, I6A) must be used. This supply voltage is activated as
soon as "Voltage Measurement" is configured for the relevant channel.
Device Specifications
I/O Modules > Analog I/O Modules
2019/04/17 3ADR010121, 13, en_US 485