Siemens SINUMERIK 840D sl Function Manual page 118

Several Operator Panels on Several NCUs, Distributed Systems (B3)
Several operator panel fronts and NCUs with control unit management option
Suppression strategy
The PLC program "Control Unit Switchover" operates according to the
● priorities of the control units and
● the active processes
The priority depends on the parameter mmc_typ in configuration file NETNAMES.INI (see
Section "Structure of the configuration file"). The Control Unit Switchover program on the
PLC evaluates this parameter according to the following table:
HMI property
Server
Main control panel
Secondary control panel
OEM-MMC 3
OEM-MMC 2
OEM-MMC 1
OEM-MMC 0
Suppression rules
The following rules apply for control unit suppression:
● Higher priority suppresses lower priority.
● In the event of identical priority, the active control unit is suppressed.
The following restrictions apply:
● Servers cannot be suppressed, as they require a permanent connection to each NCU.
● Control units on which the following processes are active cannot be suppressed:
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– Data transfer, e.g. from/to NCU
– Control unit is in the process of switching over to this NCU
– Control unit is just changing operating mode
– OEM disables switchover
Priority
6
5
4
3
2
1
0
Function Manual, 03/2009, 6FC5397-1BP10-4BA0
Extended Functions