ABB REM 545 - Analog Output Configuration Example

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1MRS750915-MUM
Machine Terminal
Technical Reference Manual, General
REM 54_
the Output range parameter. The transition of the AO#IV state may also
generate an event. Event generation is controlled by the Event mask parameter
found in the menu Configuration/RTD1.
The output behaviour when the value attribute is outside the defined limits is as
follows:
Note that the output is also forced to 0 mA on the 4...20 mA range when the value
is below the low limit. This behavior can be used to indicate a fault to the receiver.
5.1.10.3. Analog output configuration example
The analog outputs are supported in the Relay Configuration Tool by the
MEAO1...MEAO4 analog output function blocks. As an example, to display the
measured value of neutral current on an analog gauge, the neutral current
measurement block MECU1A is connected to MEAO1, which in turn is connected
to the RTD1_6_AO1 global variable. The output invalid signal RTD1_6_AO1IV is
connected to the MMIALAR1 function block to achieve a visual indication of a
fault. The MEAO_ function blocks contain the parameters necessary for scaling the
measured value to fit the selected output range. The MEAO_ function blocks also
limit the output change frequency to achieve a tolerable system load.
A060254
Fig. 5.1.10.3.-1 Analog output configuration example
Output range Value of AO# Output current Invalidity attribute AO#IV
0...20 mA >20 20 mA TRUE
0...20 0...20 mA FALSE
<0 0 mA TRUE
4...20 mA >20 20 mA TRUE
4...20 4...20 mA FALSE
<4 0 mA TRUE