ABB Symphony Harmony Series, Instruction, Page: 131 / 402

3 - 2 WBPEEUI240751C0
Inputs and Outputs
Data Conversion
An I/O block that supports analog inputs reads currents or
voltages at its input channels, scales and converts the inputs
to real values in engineering units, then reports the input val-
ues to the Harmony controller. The block provides channel sta-
tus information along with each reported input.
High and low level inputs are converted to the proper engineer-
ing units based on input type and engineering unit high and
low value specifications. Thermocouple and RTD inputs are
converted to the proper engineering units (degrees C or degrees
F) using predefined conversion tables for each type of thermo-
couple and RTD supported.
Figure 3-1. Analog Input
T0 0554C
3 -W IR E RT D
IN T E R N A L FIE L D
P O W E R E D
T R A N S M ITT E R
4-2 0 m A
+
+
+
+
+
C
–
–
–
–
–
S IN G LE -EN D E D
O R
D IFF E R E N TIA L
VO LTAG E
V
S O U R C E
± 1 0 V O R
± 10 0 m V
T H E R M O C O U P L E
E X T ER N AL F IE LD
P O W E R E D
+24 V D C
4 -2 0 m A
T R A N S M IT TE R
C O M M O N
R
LE A D 1
R
LE A D 2