Siemens SINUMERIK 840D sl Function Manual page 1433

MCP switchover
As an option, an MCP assigned to the HMI can be switched over at the same time. To
achieve this, the MCP address must be entered in the "mstt_adress" parameter of the
NETNAMES.INI configuration file on the HMI and "MCPEnable" must be set to TRUE. The
MCP of the passive HMI is deactivated so that there is only ever one active MCP on an NCU
at one time.
Boot condition
To prevent the previously selected MCP being reactivated when the NCU is restarted, input
parameters
MCP1BusAdr = 255 (address of 1st MCP) and MCP1STOP =TRUE (deactivate 1st MCP)
must be set when FB1 is called in OB100.
Approvals
When one MCP is switched over to another, any active feed or axis enables will be retained.
Note
Keys actuated at the moment of switchover remain operative until the new MCP is activated
(by the HMI, which is subsequently activated). The override settings for feedrate and spindle
also remain valid. To deactivate the activated keys, in case of the falling edge of the signal
DB10, ... DBX104.0 (MCP 1 ready) the input image of the machine control signals is to be
laid on the non-actuated signal level. The override settings should remain unchanged.
Measures for deactivating keys must be implemented in the PLC user program, see example
"Override Changeover".
The call is permitted only in cyclic program OB1.
Basic logic functions: PLC basic program solution line (P3 sl)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0
Detailed description
2.12 Block descriptions
159