ABB Symphony Harmony Series, Инструкция, Страница: 132 / 402

Inputs and Outputs
WBPEEUI240751C0 3 - 3
Calibrations
No field calibrations for analog inputs are required. The elec-
tronics automatically perform the following adjustments to the
raw analog inputs depending on input type:
•
Drift correction using onboard zero and span reference
voltages.
•
Lead wire resistance adjustment for low level, thermocou-
ple, and RTD inputs.
•
Cold junction temperature compensation for thermocouple
inputs using either an internal or external cold junction
reference.
Analog Output
The following analog outputs are supported (Fig. 3-2 ):
•
4 to 20 milliampere high level.
•
1 to 5 VDC high level.
Data Conversion
An I/O block that supports analog outputs receives output
demand values in engineering units from the Harmony control-
ler, scales the demand values to percentages of output, and
converts them to analog voltages or currents at the output
channels. User selectable default states of zero percent, 100
percent, or hold output are provided.
Calibrations
The electronics automatically adjust analog outputs to com-
pensate for supply voltage variations. Field calibration of ana-
log outputs is not required.
Figure 3-2. Analog Output
IN T ER N AL F IE LD
PO W ER E D
1 -5 V O R
4 -2 0 m A
+
–
LOA D
T 00 55 5 A