Siemens SIMATIC S5-115U User Manual page 181

S5-115U Manual
OB No. Function
OB must be user-programmed and be called by the operating system
OB1 Cyclic program scanning
OBs for interrupt-driven and time-controlled program scanning
OB2 Interrupt A:
OB3 Interrupt B:
OB4 Interrupt C:
OB5 Interrupt D:
OB6 Interrupt generated by internal timers
OB10
Time-controlled
OB11
program scanning
OB12
(variable in each case: 10 msec. to 10 min.)
OB13
OBs for controlling restart characteristics
OB21 Manual switch on (STOP RUN)
OB22 Automatic switch on when power is restored
OBs for handling programming errors and PLC faults
OB19 When a block is called which has not been loaded
OB23 Time-out during individual access to the S5 bus
(e.g. LPB, LIR, etc.)
OB24 Time-out during update of the process image and the
interprocessor communication flags
OB27 Substitution error
OB32 Transfer errors in DB or with GDB operation
OB34 Battery failure
OBs which offer operating functions
OB31 Scan time triggering
OB160 Programmable time loop
OB251 PID algorithm
OB254 Read in process I/O image
OB255 Output process I/O image
OB available
EWA 4NEB 811 6130-02b
Table 7-3. Overview of Organization Blocks
Digital input module -434
and IP generate interrupt
IP generates interrupt
IP generates interrupt
IP generates interrupt
Introduction to STEP 5
OB integrated in CPU
941 942 943 944
7-9