Instruction manual

Integer Compares

890USE18300 September 2003

Outside-the-window Integer Compare Block

Summary An outside-the-window integer compare block performs a comparison between an

analog input value and a window of values bounded by two thresholds. The input

value is represented as an integer in the range -32 768 to +32 767. The software

lets you assign values to the two thresholds (TH 1 and TH 2) along with a delta (∆)

value, which acts as an hysteresis around TH 1 and TH 2. The block produces a

Boolean result as its output.

Structure of an

Outside-the-

window

Compare Block

A block diagram for an outside-the-window integer compare is shown below:

The block has two inputs—an enable input and one operational input. The enable

input turns the block on or off. The operational input sends a word value to the block

that will be compared against the thresholds.

The block also has three preset values (See Configuring Preset Values for a Reflex

Block, p. 27), which you must specify—TH 1, TH 2 and a ∆ for hysteresis around the

TH 1 and TH 2 values. The range of values between TH 1 - ∆ and TH 2 + ∆

comprises the window against which the operational input value will be compared.

The output is a Boolean 1 when the operational input value is outside the window

(less than TH 1 - ∆ or greater than TH 2 + ∆) and a Boolean 0 when the input value

is not outside the window (greater than or equal to TH 1 + ∆ but less than or equal

to TH 2 - ∆). The output remains unchanged when the operational input is greater

than or equal to TH 1 - ∆ but less than TH 1 + ∆, or when it is greater than TH 2 - ∆

but less than or equal to TH 2 + ∆.

output

enable

operational input

outside-the-window compare

threshold 1 +/-

∆

threshold 2 +/-

∆