Siemens CPU 948 User Manual

Organization blocks for reaction to device or program errors
1)
Block Function and call criterion
OB 28 Timeout input byte IB 0
(process interrupts)
OB 29 Timeout distributed I/Os, extended address volume
OB 30 Timeout and parity error (PARE) accessing the user memory
(OB 31) (set cycle monitoring time)
2)
OB 32 Load and transfer error accessing data blocks (TRAF)
OB 33 Collision of timed interrupts (WEFES/WEFEH)
OB 34 Error setting up a data block (G DB/GX DX)
OB 36 Error in self test
1)
If the OB is not programmed, the CPU changes to the stop mode in the event of an error. EXCEPTION: if OB 19
(logic block not loaded), OB 23 or OB 24, OB 29 (timeout) or OB 33 (collision of timed interrupts) do not exist,
there is no reaction!
2)
OB 31 only exists in the CPU 948 for the sake of compatibility.
To set the cycle monitoring time, you should use data block DX0 (refer to Chapter 7)
OB 31 is called once during the start-up, if loaded. You can also use it to set the cycle monitoring time by programming
the following STEP 5 operations in it:
:L KF +nnn
:BE
nnn is a decimal number. The cycle monitoring time is obtained from "nnn
*
10 ms".
Operating system organization blocks of the CPU 948
Block Function
OB 0 Internal block belonging to operating system
Program, Organization and Sequence Blocks
CPU 948 Programming Guide
C79000-G8576-C848-04
2 - 21

Siemens CPU 948 Specifications

General

Brand	Siemens
Model	CPU 948
Category	Controller
Language	English