User`s guide

Function Blocks
Function Block Attributes
54 UMC800 Control Builder User’s Guide Release E
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Table 13 Function block attributes
Item Description
1
Blocks have a rectangular graphic form which varies in size depending on number of inputs and
outputs that the block possesses. The block type determines the type of operation or algorithm that the
block performs.
2
Each block has type identification label of up to five characters. The label is an abbreviation for the
operation or algorithm that the block performs. Each block has a number which is a reference that is
assigned by the Control Builder to uniquely identify the function block. A few blocks have reserved
block numbers.
3
Block numbers from 1 to 250 are assigned in the sequence that they are programmed. This number
determines the order in which blocks are processed. The order can be changed through the
“Configure” menu “Execution Order” selection.
ATTENTION: During UMC800 Controller operation, control blocks are executed in numerical order;
lowest numbered blocks are executed first.
4
Loop blocks and the Setpoint Programmer and Scheduler blocks have unique user-assigned tag
names consisting of up to eight characters. They are used to identify blocks for operator displays. Note
that tag names are automatically displayed in capital letters.
5
Pin labels consisting of up to five characters help identify block’s inputs and outputs.
6
Block outputs can be labeled with a “Signal Tag” consisting of up to eight characters. Signal tags are
used to display value/state of block output signals on operator displays and for discontinuous wires.
7
Most blocks have configuration parameters to tailor operation to control requirements at hand and can
only be set or changed through the function block parameters dialog box.
8
Outputs exit a block as lines from bottom or right-hand side and reflect the block’s execution.. Outputs
can be connected to any number of control block inputs, but, they cannot be connected to:
• an output of another block,
• a named variable , or
• a constant
Note that unused outputs can be left unconnected.
9
The block’s input signals are variables that are used by the function in calculating the outputs. Inputs
enter block from top or left-hand side. Inputs can be from:
• an output of another block,
• a named variable (values that can be changed from the operator interface — maximum 150)
• A connector that references a signal tag.
• A constant that references a signal tag.
Note that unconnected inputs will default to 0 or OFF.