Siemens SIMATIC S7-400H - Ob 122

Using I/O on the S7-400H
7-40
Automation System S7-400H Fault-tolerant Systems
A5E00068197-07
Table 7-7 OB 122
STL 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?
M01: NOP 0;
L OB122_MEM_ADDR; //Logical base address affected
L W#16#C;
== I; //Module B?
SPBN CONT; //If no, continue with CONT
//PZF upon access to module B
SET;
= PZF_BIT; //Set PZF bit
CONT: NOP 0;