Delta DVP-ES2/EX2/SS2/SA2/SX2/SE manual Call

2. Programming Concepts

	X0	P**
20
	CALL	P2	Call subroutine P**
24	X1
	Y1
	FEND
P2	Y0
(subroutine		subroutine
P2)	Y1
	SRET	subroutine return

Interrupt pointer I: used with application instruction API 04 EI, API 05 DI, API 03 IRET. There are four types of interruption pointers. To insert an interruption, users need to combine EI (enable interruption), DI (disable interruption) and IRET (interruption return) instructions

1.External interrupt

„When input signal of input terminal X0~X7 is triggered on rising-edge or falling-edge, it will interrupt current program execution and jump to the designated interrupt subroutine pointer I000/I001(X0), I100/I101(X1), I200/I201(X2), I300/I301(X3), I400/I401(X4), I500/I501(X5), I600/I601(X6), I700/I701(X7). When IRET instruction is executed, program execution returns to the address before interrupt occurs.

„When X0 (C243) works with I100/I101 (X1), X0/X1 (C246, C248, C252) works with I400/I401, the value of C243, C246, C248, C252 will be stored in (D1240, D1241)

„When X2 (C244) works with I300/I301 (X3), X2/X3 (C250, C254) works with I500/I501, the value of C244, C250, C254 will be stored in (D1242, D1243).

2.Timer interrupt

PLC automatically interrupts the currently executed program every a fixed period of time (2ms~99ms) and jumps to the execution of a designated interruption subroutine

3.Counter interrupt

The high-speed counter comparison instruction API 53 DHSCS can designate that when the comparison reaches the target, the currently executed program will be interrupted and jump to the designated interruption subrountine executing the interruption pointers I010, I020, I030, I040, I050 ,I060, I070, I080..

4.Communication interrupt

I140:

Communication instruction RS (COM1 RS-232) can be designated to send interrupt request when specific charcters are received. Interrupt I140 and specific characters is set to low byte of D1167.

This function can be adopted when the PLC receives data of different length during the

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