Allen-Bradley ProcessLogix 1756-IA16, Reference Manual, Page: 57 / 120

Publication 1757-RM810A-EN-P - May 2002
Functional Blocks 3-17
CHECKBAD
DELAY
EQ (Equal)
Description Provides bad input handling for desired input.
Function Checks if input (IN) value equals NaN.
If IN = NaN
Then, OUT = ON
Else, OUT = OFF
Inputs IN = Real number
Outputs OUT = Boolean value
Parameters IN
ORDERINCM
OUT
Description Provides the ability to delay the output (OUT) response to the given input (IN) by one sample time delay.
Function The OUT always follows the input (IN) action after one sample time delay.
Inputs IN = Boolean value
Outputs OUT = Boolean value
Parameters DELAYTIME
IN ORDERINCM
OUT
Description Provides a 2-input Compare Equal (with deadband range) function, meaning that it compares two inputs for equality
within a specified deadband range.
Function Turns the digital output (OUT) ON only when the two inputs (IN [1] and IN [2]) are considered equal within a specified
deadband range.
Inputs IN [1..2] = real numbers
If only 1 input connection is configured, an input port is displayed for parameter TP and the value of TP is used instead
of IN [2].
If IN [1] and/or IN [2] are NaN (Not a Number), OUT = OFF.
DEADBAND1, DEADBAND2 and TP have the same data types as the inputs.
DEADBAND1 and DEADBAND2 must satisfy this constraint: 0 <= DEADBAND1 <= DEADBAND2
Outputs OUT = Boolean value controlled by the status of the input signals.
Comparison blocks should set their outputs to Off if any of the inputs are NaN. This “fail safe” behavior is consistent
with the IEEE 754 floating point standard.
Parameters DEADBAND1
DEADBAND2
IN [0..2]
NUMOFINPUTS ORDERINCM
OUT
TP
Spare Allen-Bradley Parts