Siemens S5-100U - Program Processing

Introduction to STEP 5 S5-100U
7.4 Program Processing
Some of the organization blocks (OBs) are responsible for structuring and managing the control
program.
These OBS can be grouped according to the following assignments:
• OBs for START-UP program processing
• One OB for cyclic program processing
• OBs for time-controlled program processing
• OBs for (process) interrupt-driven program processing
The S5-100U has additional OBs whose functions are similar to those of integral function blocks
(e.g., PID control algorithm). These OBs are described in chapter 9.
Section 7.3.1 summarizes all of the OBs.
Comparing Programming Possibilities for CPU 100, CPU 102, and CPU 103
Table 7-5. Programming Possibilities
CPU CPU 100 CPU 102 CPU 103
Cyclical Yes Yes Yes
Interrupt-driven No No Yes
(for 8MA02 and higher)
Time-controlled No No Yes
(for 8MA02 and higher)
Integral FBs No Yes
(for 8MA02 and higher)
Yes
Graph 5 No No Yes
Programmable FBs No No Yes
Beginning with section 7.4.2, you learn which special organization blocks each of the CPUs has
available to perform the programming tasks described in Table 7-5. You also learn which pre-
cautions you need to take when you program.
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