Supported Modes
If SELECT_TYPE is Middle, sort the remaining inputs by value. If there are 3 or 4
values, discard the highest and lowest value. If two values are left, compute their
average. Transfer the value to the output of the block. Set SELECTED to zero if an
average was used, else set SELECTED to the number of the input with the middle
value.
If SELECT_TYPE is Average compute the average of the remaining inputs and transfer
the value to the output of the block. Set
SELECTED to the number of inputs used in the average.
Limit Processing
The computations to determine high and low limit conditions for the output can be
complex. They should be done to the best of the designer's ability. The limits of OUT
should be able to tell a PID to stop integrating if the measurement cannot move.
Supported Modes
O/S, Man, and Auto.
Alarm Types
Standard block alarm.
Mode Handling
Standard.
Status Handling
If there are no inputs used, or fewer than MIN_GOOD inputs, then the status of OUT
shall be set to Bad Non-specific.
The SELECTED output shall have Good(NC) status, unless the block is out of service.
Status options for Use Uncertain as Good and Uncertain if Manual shall be supported.
Initialization
Standard.
Power Failure Recovery
Standard.
151
IS (SIGSEL) Function Block