Startup Operating State - Siemens SIMATIC S7-1500 System Manual

Commissioning
11.4 Operating and system states
No. in dia­ Primary CPU
gram
RUN → RUN-Syncup
③
The two user programs are synchronized for redundant mode. The primary CPU copies the contents of the load
and work memory to the backup CPU. The backup CPU catches up with user program processing on the primary
CPU. After successful synchronization, the memory content is identical on the two CPUs.
RUN-Syncup → RUN-Redundant
④
After the SYNCUP CPUs go to RUN-Redundant mode. Both CPUs process the user program synchronously.
The state transition also triggers OB 72 and possibly OB 70. You can find more information on the OB 72 and
OB 70 in the section Programming the S7-1500R/H (Page 246).
See also
Programming the S7-1500R/H (Page 215)
11.4.2

STARTUP operating state

Startup processing (in the primary CPU only)
STARTUP is only executed by the primary CPU.
In STARTUP, the primary CPU behaves just like an S7‑1500R/H standard CPU.
Response
Before the CPU starts to execute the cyclic user program, a startup program is executed.
By suitably programming startup OBs, you can initialize variable tags for your cyclic program
in the startup routine. You can program one or more startup OBs, or none at all.
Points to note
• All outputs are disabled or respond as configured for the given module: They provide a
configured substitute value or retain the last value output and switch the controlled
process to a safe operating state.
• The process image is initialized.
• The process image is not updated.
To read the current state of inputs during STARTUP, you can access inputs with direct I/O
access.
To initialize outputs during STARTUP, you can write values via the process image or with
direct I/O access. However, the values are first output at the outputs during the transition
to the RUN operating mode.
• The CPU always starts up in warm restart mode.
– If you define data as retentive, its content is retained beyond program startup after
– The non-retentive bit memories, timers and counters are initialized.
– The non-retentive tags in data blocks are initialized.
• During STARTUP, cycle time monitoring is not yet running.
266
System state
RUN-Solo → SYNCUP
SYNCUP → RUN-Redundant
STOP or a power failure.
Backup CPU
STOP → SYNCUP
SYNCUP → RUN-Redundant
S7-1500R/H redundant system
System Manual, 11/2022, A5E41814787-AD