ISPSoft User Manual

Chapter 9 Function Block Diagram
following two points when they delete an input node.
(a) The topmost input node of an AND/OR block, e.g. M0 in the figure below, can not be deleted.
(b) If an AND/OR block has only two input nodes, neither of the input nodes can not be deleted.
9.2.4 Inverse Logic
Users can insert inverse logic into a Boolean position in a function block diagram, e.g. an input node
which represents a Boolean device or a symbol whose data type is BOOL, an output node which
represents a Boolean device or a symbol whose data type is BOOL, the En pin of a function block,
or the En pint of an applied instruction. However, users have to notice that they are not allowed to
insert inverse logic into the pins of a function block/an applied instruction to which operands are
assigned.
• Graphical representation
• Example
Example 1: The state of M0 is inverted, and the inversion result is sent to M1. Likewise, the coil
M1 will be driven if the normally-closed M0 is OFF.
Example 2: The inverse logic inserted into the output node indicates that the result of the
operation is inverted. The inversion result is sent to M3.
Example 3: If M0 is ON, the function block BLACK will be executed. If M0 is OFF, the function
block WHITE will be executed.
Example 4: The figure below is an incorrect example. Inverse logic can not be inserted into a
node which does not represent a Boolean device or a symbol whose data type is
BOOL.
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