User`s guide

Function Blocks
Function Block Categories and Types
64 UMC800 Control Builder User’s Guide Release E
1/01
Logic category
Logic notes
• The UMC800 logic function blocks will replace from 40 to 60 rungs of ladder logic on the average (for
straight combinations or Boolean functions, timing and counting) assuming an average of 6 logic
functions per rung consuming 3-4 blocks.
• Extensive PLC ladder logic used for analog functions, PID, setpoint programmer, alarms, interface with
operator interface, pushbuttons, lamps is replaced by UMC800 function blocks and displays. (Extensive
conditional alarming may expand logic requirements)
• All logic blocks are executed in order according to sequence.
• All fast-logic logic blocks are executed and outputs updated in 100ms - used to capture faster transitions
such as a pushbutton depression on a panel.
• All normal logic blocks are executed at analog update rate.
• You can mix fast and analog scan time logic blocks.
• If you wish Discrete Input function blocks to be scanned prior to execution of succeeding blocks, reorder
their sequence order ahead of these blocks.
• You can place any number of connections to the output of a block, or if using signal tags for this
purpose, they may be used anywhere.
For examples of Logic Block applications, refer to Appendix A – Logic Application Examples.
Function block types
Table 18 lists the function block types in the Logic category. (Also see Fast Logic category.)
Table 18 Logic category function block types
Block Type Description Graphic Form
DI Digital Input - Provides the digital status of a digital input.
The output states may be inverted.
DO
Digital Output - Directs a digital status to a physical logic
output. The output status may be inverted.
8DI Eight Digital Inputs - Provides read access for up to 8
physical digital inputs. It minimizes the number of blocks
required to configure all of the Digital I/O required in a
system. The output states may be inverted.