Ob 122 - Siemens SIMATIC S7-400H Manual

Using I/O on the S7-400H
Table 7-7
STL
M01:
CONT:
7-40

OB 122

Explanation
// Does module A cause PZF?
L OB122_MEM_ADDR; //Logical base address affected
L W#16#8;
== I; //Module A?
SPBN M01; //If no, continue with M01
//PZF upon access to module A
SET;
= PZF_BIT; //Set PZF bit
SPA CONT;
// Does module B cause PZF?
NOP 0;
L OB122_MEM_ADDR; //Logical base address affected
L W#16#C;
== I; //Module B?
//If no, continue with CONT
SPBN CONT;
//PZF upon access to module B
SET;
= PZF_BIT; //Set PZF bit
NOP 0;
Automation System S7-400H Fault-tolerant Systems
A5E00068197-07