Chapter 7 Usage of Various Functions
7-17
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

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.
External input signal
Scan program
External contact
interrupt program.
Scan program
In case of occurrence of external
interrupt signal pause being executed
scan program and process interrup
t
program
End the interrupt program
process then resume to
execute scan program