Siemens SINUMERIK 840D sl Programming Manual page 223

Further information
Activation status (<state>)
● <state>=2
● <state>=1
● <state>=3
● <state>=0
Movement of protection zones for (pre)activating
The offset can take place in 1, 2, or 3 dimensions. The offset refers to:
● the machine zero in workpiece-specific protection zones.
● the tool carrier reference point F in tool-specific protection zones.
Status after booting
Protection zones can be activated straight after booting and subsequent reference point
approach. The system variable $SN_PA_ACTIV_IMMED[<n>] or
$SC_PA_ACTIV_IMMED[<n>] must be set to TRUE for this purpose. They are always
activated with Status = 2 and have no offset.
Multiple activation of protection zones
A protection zone can be active simultaneously in several channels (e.g. tailstock where
there are two opposite sides). The protection zones are only monitored if all geometry axes
have been referenced.
The following applies:
● The protection zone cannot be activated simultaneously with different offsets in a single
● Machine-oriented protection zones must have the same orientation on both channels.
Job Planning
Programming Manual, 03/2013, 6FC5398-2BP40-3BA1
A protection zone is generally activated in the part program with status = 2.
The status is always channel-specific even for machine-oriented protection zones.
If a PLC user program provides for a protection zone to be effectively set by a PLC user
program, the required preactivation is implemented with status = 1.
In the case of preactivation with conditional stop, the system never stops in front of a
preactivated protection zone which has been violated. The stop only occurs if the
protection zone has been activated. This facilitates uninterrupted processing if the
protection zones have only been activated in special cases. N.B. The system may move
into the protection zone as a result of the braking ramp if the protection zone is only
activated immediately prior to motion.
Preactivation with conditional stop is realized using status = 3.
The protection zones are deactivated and therefore disabled with Status = 0. No shift is
required
channel.
3.2 Activating/deactivating protection zones (CPROT, NPROT)
Protection zones
223