Siemens SINUMERIK 840D sl Function Manual page 203

2. MMC_1 cannot change to the passive operating mode (processes which do not permit a
Figure 2-33
Extended Functions
Function Manual, 01/2008, 6FC5397-1BP10-3BA0
Several Operator Panels on Several NCUs, Distributed Systems (B3)
If an MCP is assigned to the MMC and activated, it is now deactivated by the PLC.
The PLC gives permission for a changeover to the active operating mode with
MMC2_ACTIVE_PERM = TRUE.
MMC_2 changes state and acknowledges with MMC2_ACTIVE_CHANGED = TRUE. If
an MCP is assigned to MMC_2, it is now activated by the PLC.
changover are running on MMC_1):
MMC_1 sets MMC1_CHANGE_DENIED = TRUE, the change of state cannot be
completed.
The PLC acknowledges with MMC1_CHANGE_DENIED = FALSE and gives permission
to MMC_1 to remain in active mode with MMC1_ACTIVE_PERM = TRUE. By sending
MMC2_CHANGE_DENIED = TRUE, it notifies MMC_2 that MMC_1 cannot switch over to
passive mode.
MMC_2 then acknowledges with MMC2_CHANGE_DENIED = FALSE and remains in
passive operating mode.
MMC_1 requests active mode, MMC_2 is in passive mode
2.15 Examples
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