Siemens SINUMERIK 840D sl Function Manual page 205

B3: Several operator panels connected to several NCUs, distributed systems - only 840D sl
Operator panel coming
Once the operator panel has sent an online request to the target PLC and received online
permission from it, it can set up a link to the target NCU.
It goes online and notifies the PLC with (station active) S_ACT/CONNECT that it has linked up
with the NCU.
The operator panel sets up its sign of life signal in accordance with the allocated interface.
The operator panel then requests
● in the case of operator panel front: active operating mode on the target NCU,
● in the case of server: operating focus on the target NCU.
The PLC then activates HMI sign-of-life monitoring for the new operator panel.
See: Active/passive operating mode
See: Operating focus switchover in server mode
Operator panel going
An operator panel aborts communication with an NCU.
Communication can be aborted for two different reasons:
1. The operator wishes to switch the operator panel to another NCU. The operator panel
2. The operator panel is suppressed from the PLC by the online request from another
Suppression
Two operator panels are linked online to an NCU, each is occupying an HMI-PLC interface.
A third operator panel would like to go online.
The PLC must suppress one of the two operator panels according to a predefined strategy. It
sends the operator panel to be suppressed an offline request (OFFL_REQ_OP/OK) to abort
communication with the NCU. The operator panel returns a positive or negative
acknowledgement to the PLC:
Positive:
OFFL_CONF_PLC/OK
Operator panel breaks off the link to the NCU and switches to the offline state.
The HMI sign of life in the PLC changes from TRUE to FALSE.
Extended Functions
Function Manual, 09/2009, 6FC5397-1BP20-0BA0
has sent an online request to the target PLC and received online permission
(ONL_PERM/OK). It has notified the online PLC of its intention to switch over with
OFFL_REQ_OP/OK and received a positive acknowledgement (OFFL_CONF_OP/OK). Due
to the switchover to the target NCU, the HMI sign of life in the online PLC is changed
from TRUE to FALSE. The falling edge combined with the sequence described above
signals to the online PLC that the operator panel has broken off the link to the online
NCU. If an MCP is assigned to the operator panel and activated, it is now deactivated by
the PLC. Passive operating mode is set in the PLC for the operator panel which has been
suppressed.
See: Active/passive operating mode
operator panel. See "Suppression".
2.15 Examples
205