Emerson Rosemount OCX8800 - Application Information; Figure 7-31 Input Selector Function Block Application Example (SEL_TYPE = Max); Status Handling

Section 7: Foundation
Fieldbus
April 2017
Instruction Manual
IM-106-880C, OI
16
2
Status
Handling
7.15.5 Status Handling
In Auto mode, OUT reflects the value and status quality of the selected input. If the number of
inputs with Good status is less than MIN_GOOD, the output status will be Bad.
In Man mode, the OUT status high and low limits are set to indicate that the value is a constant
and the OUT status is always Good.
In the STATUS_OPTS parameter, the following options can be selected from to control the status
handling:
• Use Uncertain as Good: sets the OUT status quality to Good when the selected input
status is Uncertain.
• Uncertain if in Manual mode: The status of the Output is set to Uncertain when the
mode is set to manual.
The instrument must be in Manual or Out of Service mode to set the status option.
7.15.6 Application Information
The ISEL function block can be used to select the maximum temperature input from four inputs
and send it to a PID function block to control a process water chiller (Table 7-31) or it can use the
block to calculate the average temperature of the four inputs (Table 7-32).
Figure 7-31 Input Selector Function Block Application Example (SEL_TYPE = max)