Siemens SINUMERIK 828D Function Manual page 119

Activate
The preactivated protection zones can be activated from the PLC user program:
DB21, ... DBX8.0 to DBX9.1 (Activate machine-related protection zone 1 - 10)
DB21, ... DBX10.0 to DBX11.1 (Activate channel-specific protection zone 1 - 10)
Deactivation
Protection zones activated from the part program cannot be deactivated by the PLC user program.
Note
It follows from the rules listed above that protection zones that should be activated via the
PLC user program are intended specially for this. Preactivation in the part program is only
useful for these protection zones.
For protection zones that are known only in the part program and not in the PLC user
program, only activation in the part program makes sense.
Automatic activation after the control powers up
The configuration for automatic activation of a protection zone after the control powers up is performed via the
following system variable:
• Channel-specific protection zone:
$SC_PA_ACTIV_IMMED[ n ]
• Machine or NC-specific protection zone:
$SN_PA_ACTIV_IMMED[ n ]
With automatic activation, no relative offset of the protection zone is possible.
Block search with calculation
For block search with calculation, the last programmed activation state of a protection zone is always taken into
account.
Program test
In automatic modes, activated and preactivated protection zones are monitored even during program control:
PROGRAM TEST.
Basic Functions
Function Manual, 09/2011, 6FC5397-0BP40-2BA0
A3: Axis Monitoring, Protection Zones
2.3 Protection zones
119