LG Electronics 120S user manual Usage of Various Functions External Interrupt Function

Chapter 7 Usage of Various Functions

7.1.4 External Interrupt Function

MASTER-K120S Series can perform max 4(economic) or 8(standard) points of external contact interrupt by using input of main unit without special interrupt module.

1) Usage

This function is useful to execute a high speed execution regardless of scan time.

2) Minimum processing time.

	Type	Standard		Economic
	10 ㎲	2 points (P0, P1)		None
	50 ㎲	6 points (P2 ~ P7)		4 points (P0 ~ P3)
3) Operating explanation
	External input signal
			Scan program			Scan program
	In case of occurrence of external				External contact	End the	interrupt program
	interrupt signal pause being executed				interrupt program.	process	then resume to
	scan program and process interrupt					execute scan program
	program

4)Function

(1)Max. 8 points can be used to external interrupt input within P000 ~ P007.(P000~P003 for economic type)

(2)The no. of external interrupt is decreased by using other interrupt (time driven interrupt and HSC driven task)

(3)The execution conditions of external interrupt is divided into following 3 kinds.

-Rising edge : Interrupt occurs at rising edge of external Interrupt contact point.

-Falling edge : Interrupt occurs at falling edge of external Interrupt contact point.

-Rising & falling edge : Interrupt occurs at both edge of external Interrupt contact point.

(4)In the economic type, falling edge and rising & falling edge interrupt are not available.

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