Distributed Configuration, Ob 86; Embedding An Op - Siemens SIMATIC FM 353 Manual

Programming the Technological Functions
Information on testing the user program
When testing the user program with "Set breakpoint", please note that it is not al-
ways possible to resume the program scan with the FM 353 after the breakpoint
has been reached (for technical reasons).
For example, movements activated by the user program cannot be halted when
the user program has reached the breakpoint.
The program can be resumed by executing a restart (CPU: STOP/RUN), by reset-
ting the axis, or by changing the operating mode.
6.1.3

Distributed configuration, OB 86

If system operation must be maintained with an FM 353 despite a faulty link be-
tween CPU and distributed I/Os (DP), OB 86 is to be linked into the user program.
In OB 86, provisions (e.g. set flag and evaluate in OB) must be made to prevent
OB 1 communication with the FM 353 in case of a failure. To enable synchroniza-
tion of the user program and the FM, the POS_INIT block (corresponding to exe-
cution in OB 100) is to be linked on re-establishing the link. Additionally, OB 122
(I/O access error) must be loaded in the CPU.
6.1.4

Embedding an OP

Part of the AW-DB, namely the "Data field for operator control/monitoring"
(DBB496 to DBB515), is used to store signals/data for an OP as per the preconfi-
gured operator interface. In order to initiate actions, the relevant signals/data have
to be transferred to the interface (relevant area in the AW-DB) via the user pro-
gram (see Section 6.7, example 4).
6-6
FM 353 Stepper Drive Positioning Module
6ES7 353-1AH01-8BG0