Siemens SINUMERIK 840Di Function Manual page 1065

Releases
When one MCP is switched over to another, any active feedrate or axis enabling signals may
be transferred at the same time.
Note
Keys actuated at the moment of switchover remain operative until the new MCP is activated
(by the MMC, which is subsequently activated). The override settings for feedrate and
spindle also remain valid. To deactivate actuated keys, the input image of the machine
control signals must be switched to non actuated signal level on a falling edge of
DB10.DBX104.0. The override settings should remain unchanged.
Measures for deactivating keys must be implemented in the PLC user program
(see below: Example of override switchover).
Declaration of function
FUNKTION_BLOCK FB9
VAR_INPUT
END_VAR
VAR_OUTPUT
END_VAR
Power Line Basic PLC Program (P3)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
Ack :BOOL;
OPMixedMode: BOOL:= FALSE;
ActivEnable :BOOL:= TRUE;
MCPEnable :BOOL:= TRUE;
Alarm1 :BOOL;
Alarm2 :BOOL;
Alarm3 :BOOL;
Alarm4 :BOOL;
Alarm5 :BOOL;
Alarm6 : BOOL ;
Report : BOOL ;
ErrorMMC : BOOL ;
//Acknowledge alarms
// Hybrid operation with non-M-to-N-
enabled OP deactivated
// Not supported
// Activate MCP switchover
// Alarm: Error in MMC bus address, bus
type!
// Alarm: No confirmation MMC1 offline!
// Alarm: MMC1 is not going offline!
// Alarm: No confirmation MMC2 offline!
// Alarm: MMC2 is not going offline!
// Alarm: Queuing MMC is not going online!
// Message: Sign-of-life monitoring
// Error detection MMC
Detailed description
2.12 Block descriptions
2-153