Instruction manual

Introduction
890USE18300 September 2003 17
Compare Action
Types
A compare block takes a word as its operational input and compares that value
against a predefined threshold value or a window of values. An integer compare
block accepts operational inputs with integer values in the range -32 768 to +32 767.
An unsigned compare block accepts operational inputs with integer values in the
range 0 to 65 535.
Integer compare blocks generally take their operational inputs from Advantys
STB analog input modules. Advantys analog modules use the IEC format for
handling data. In this format, the most significant bit is always a dedicated sign
bit, and the remaining 15 bits are able to represent values up to 32 767.
Unsigned compare blocks generally take their operational inputs from virtual
modules (See The Virtual Module, p. 28) or from the outputs produced by counter
reflex actions (See Nesting Two Reflex Blocks, p. 36). These input sources
produce unsigned values with 16-bit resolution (values as high as 65 535).
Integer compare blocks and unsigned compare blocks both support four action
types:
less-than-threshold compares, where the output is a Boolean 1 when the
operational input value is less than a user-defined threshold value
greater-than-threshold compares, where the output is a Boolean 1 when the
operational input value is greater than a user-defined threshold value
inside-the-window compares, where the output is a Boolean 1 when the
operational input value is within a range of values bounded by two user-defined
thresholds
outside-the-window compares, where the output is a Boolean 1 when the
operational input value is outside a range of values bounded by two user-defined
thresholds