DVC6000f Series
March 2006
5-114
Figure 5-17. Output Splitter (OS) Function Block
RCAS IN
CAS
IN
OS
OUT 1
OUT
2
Output Splitter (OS) Function Block
Overview
The Output Splitter block provides the capability to
drive two control outputs from a single input. Each
output is a linear function of some portion of the input.
Back calculation support is provided using the same
linear function in reverse. Cascade initialization is
supported by a decision table for combinations of input
and output conditions.
This block is normally used in split ranging or
sequencing of multiple valve applications. A typical
split range application has both valves closed when
the splitter input is 50%. One valve opens fully as the
input drops to 0%. The other valve opens as the input
rises above 50%.
A typical sequencing application has both valves
closed at 0% input. One valve fully opens as the input
rises to 50% and the other stays shut. The second
valve opens as the input rises above 50%, and the
first valve may remain open or shut off quickly.
Because this block is in the control path, it is able to
pass limit and cascade initialization information back
to the upstream block. Table 5-47 lists the OS block
parameters and their descriptions, units of measure,
and index numbers. Figures 5-18 and 5-19 illustrate
the internal components of the OS function block.
Modes
The Output Splitter function block supports the
following actual modes:
Out of Service (OOS)—The block is not
processed. FIELD_VAL and PV are not updated and
the OUT status is set to Bad: Out of Service. The
BLOCK_ERR parameter shows Out of Service. In this
mode, you can make changes to all configured
parameters.
By using permitted mode the target mode of a block
may be restricted to one or more of the following
modes: Cas, Auto or OOS.
Initialization Manual (IMan)—The output path
is not complete (for example, the cascade−to−slave
path might not be open). In IMan mode, OUT tracks
BKCAL_IN, which allows for bumpless transfer of
control.
Figure 5-18. Output Splitter Function Block Schematic
RCAS_IN
OUT
1
CAS_IN
OUT 2
RCAS_OUT
CAS_OUT
BKCAL_IN_2
BKCAL_IN_1
IN_ARRAY
OUT_ARRAY
LOCKVAL
SP
Auto
5
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