Siemens S7-400 OB Priority, Operating State, Operating System of the CPU, Organization Block OB

Glossary

O

OB

→Organization Block

OB Priority

The operating system of the S7-400 CPU differentiates between various priority classes, for example, cyclic program processing, process interrupt-controlled program processing. Each priority class is assigned organization blocks (OBs), where the S7 user can program a reaction. As a standard, the OBs have different priorities to which they are processed when they occur simultaneously or when they interrupt each other.

Operating State

The SIMATIC S7 programmable controllers recognize the following operating states: STOP, STARTUP, RUN.

Operating System of the CPU

The operating system of the CPU organizes all functions and sequences of the CPU which are not connected to a specific control task.

Organization Block (OB)

Organization blocks form the interface between the operating system of the S7-400 CPU and the user program. The sequence in which the user program should be processed is laid down in the organization blocks.

P

Parameter

1.Variable of a STEP 7 logic block

2.Variable for setting the reaction of a module (one or more per module). Parameters can be static or dynamic.

Parameters, Dynamic

In contrast to static parameters, dynamic parameters of modules can be changed during operation by calling an SFC in the user program, for example, limit values of an analog signal input module.

Glossary-10

Automation System S7-400 Hardware and Installation A5E00850741-01