Siemens Moore 353 User Manual page 32

Function Blocks
Some users may prefer to use normalized 0-1 analog inputs for math calculations and scale outputs for display
only; in this case, the Scaler function block may be used to provide an output range (OR) for the ODC
(Operator display block).
Note how the range pointers are used in the following Factory Configured Options (FCOs). FCOs are described
in detail in the Factory Configured Options section.
•
FCO101 Single Loop Controller – The process output range AIN1 (OR) is connected to the range pointer
of the SETPT block, the PID block, the ALARM block and the process variable range of the ODC block.
As a result these blocks will be automatically rescaled when the minscale and the maxscale or the
engineering units of the Process is changed. For example, if AIN1 is scaled 0-5000, the 0-100% bargraph
on the display will represent 0-5000 when displaying the process. The A/M block, AOUT1 (Valve) output,
and the Valve input of the ODC block are scaled based on the output of the PID block.
•
FCO104 External-Set PID controller – The external setpoint is displayed as variable X in the ODC block.
Therefore, the ODC (RX) input uses the range output of the external setpoint AIN2 (OR) for scaling. The
0-100% bargraph will represent the range of AIN1 when displaying the process variable and the range of
AIN2 when displaying the X variable.
•
FCO105 Ratio Set Control – AIN1 and AIN2 are scaled 0-100% of flow. The ratio of these flows is
displayed on variable Y and the scaler function block is used to define the engineering units as a
dimensionless ratio CF/WF scaled from 0.50 –1.50.
Connections between blocks are allowed only with similar data types.
To help you quickly locate a function block:
•
In this section, function blocks are listed alphabetically by the block ID (e.g. AIN for Analog Input).
•
In Section 2, function blocks are listed by broad function (e.g. station hardware I/O).
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UM353-1
March 2003