Time-Controlled Program Processing, For Cpu 103 Version 8Ma02 And Higher - Siemens SIMATIC S5-100U System Manual

Introduction to STEP 5
7.4.4 Time-Controlled Program Processing, for CPU 103 Version 8MA02
and Higher
Time-controlled program processing can be defined as a (periodic) time signal causing the CPU to
interrupt cyclic program processing to process a specific program. Once this program has been
processed, the CPU returns to the interruption point in the cyclic program and resumes processing.
Prerequisites for time-controlled program processing
Time-controlled program processing is possible only if the following prerequisites have been fulfilled.
• Organization block OB13 must be programmed.
• The programmable controller must be set to Power ON and the RUN mode must be selected.
• Interrupt processing may not be disabled (by the IA - disable interrupt - operation). See
section 8.2.8.
• The OB13 call-up interval is set to > 0.
OB13 is available for time-controlled program processing when using CPU 103 version 8MA02 and
higher. You determine the intervals at which you want the operating system to process OB13. It is
also possible to change the call-up intervals during cyclic program processing. Cyclical program
processing continues if OB13 is not programmed.
• Setting the call-up interval
You can set the call-up interval in DB1 using the TFB: block ID. You can set the times from
10 ms to 655,530 ms (use 10-ms increments). The default for OB13 is 100 ms.
• Interrupt possibilities
OB13 can interrupt the cyclical program after any STEP 5 statement. After the current STEP 5
statement is executed, you can use process interrupts to interrupt time-controlled program
processing. After interrupt processing, time-controlled program processing continues until it is
finished.
OB13 cannot interrupt the operating system, the process interrupts (OB2), or the current time-
controlled program processing (OB13).
• Disabling/enabling the call-up
Use the IA command to disable, and the RA command to enable the OB13 call-up.
A call-up request can be stored during a call-up disable. The default is RA. See section 8.2.8.
7-28
S5-100U
EWA 4NEB 812 6120-02b