ABB REM 545 - Attributes of an Rtd;Analog Input for Machine Terminal Configuration

1MRS750915-MUM
REM 54_
61
Machine Terminal
Technical Reference Manual, General
resist3w_b
Fig. 5.1.9.6.-4 Principle diagram of the three-wire connection
With the two-wire connection principle, the IN- and GND terminals are linked
together. The resistor is connected across the IN+ and IN- inputs.
resist2w_b
Fig. 5.1.9.6.-5 Principle diagram of the two-wire connection
5.1.9.7. Attributes of an RTD/analog input for machine terminal
configuration
The value and the status (validity) of the input can be issued for each RTD/analog
input by the attributes AI# (REAL type) and AI#IV (BOOL type), where # denotes
the number of the input. These attributes are available in the machine terminal
configuration and can be used for different purposes.
Value (AI#)
The AI# value represents the filtered absolute value of the physical input with the
unit according to the selected measuring mode, i.e. V, mA, Ω or °C.
Invalidity (AI#IV)
The AI#IV attribute represents the invalidity status of the input. The attribute is set
to FALSE when the value (AI#) is valid, and to TRUE when the value is invalid. The
input is invalid when one or more of the following conditions are true: the measured
value is outside the defined limits (see the parameters Input high limit and
Input low limit), an open-loop condition is detected (only possible on
resistance and temperature measuring modes) or the continuous recalibration of the
module has failed. The value (AI#) is not locked when the invalid attribute is set to
TRUE, i.e. the invalid value is available for inspection.
SHUNT
IN -
GND
IN +
G
mA
DIF
F
+
-
Resistor sensor
SHUNT
IN -
GND
IN +
G
mA
DIF
F
+
-
Resistor sensor