STACKINT

Manages a stack of integer values.

Arguments
PUSH	BOOL	Push command (on rising edge only) add the IN value on the top of the stack
POP	BOOL	Pop command (on rising edge only) delete in the stack the last value pushed (top of the stack)
R1	BOOL	Resets the stack to its empty state
IN	DINT	Pushed value
N	DINT	Application defined stack size
EMPTY	BOOL	TRUE if the stack is empty
OFLO	BOOL	Overflow: TRUE if the stack is full
OUT	DINT	Value at the top of the stack OUT equals 0 when OFLO is TRUE

The STACKINT function block includes a rising edge detection for both PUSH and POP commands. The maximum size of the stack is 128. The application defined stack size N cannot be less than 1 or greater than 128.

This function manages invalid values as follows:

if N<1, STACKINT assumes a size of 1

if N>128, STACKINT assumes a size of 128

TIP: The OFLO value is valid only after a reset (R1 has been set to TRUE at least once and back to FALSE).

Example

(* FBD program using the STACKINT block: error management *)

(* ST Equivalence: We suppose STACKINT1 is an instance of STACKINT block *)

STACKINT1(err_detect, acknowledge, manual_mode, err_code, max_err);

appli_alarm := auto_mode AND NOT(STACKINT1.EMPTY);

err_alarm := STACKINT1.OFLO;

last_error := STACKINT1.OUT;

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