Siemens SINUMERIK 840D sl Function Manual page 1432

Detailed description
2.12 Block descriptions
2.12.7 FB 9: MtoN Control unit switchover
Description of Functions
This block allows switchover between several control units (HMI operator panel fronts and/or
MCP machine control panels), which are connected to one or more NCU control modules via
a bus system.
References:
/FB2/ Function Manual Extended Functions; Several Operator Panel Fronts on Several
NCUs, Distributed Systems (B3)
The interface between the individual control units and the NCU (PLC) is the M : N interface
in the data block DB 19, see
/FB2/ Function Manual Extended functions, Section "Data lists, Signal description".
FB 9 uses the signals of these interfaces.
Apart from initialization, sign-of-life monitoring and error routines, the following basic
functions are also performed by the block for control unit switchover:
Tabulated overview of functions:
Basic function
HMI queuing
HMI coming
HMI going
Forced break
Operating focus changeover to
server mode
Active/passive operating mode:
MCP switchover
Brief description of a few important functions
Active/passive operating mode:
An online HMI can operate in two different modes:
Active mode:
Passive mode:
After switchover to an NCU, this initially requests active operating mode in the PLC of the
online NCU. If two HMI are connected online on one NCU simultaneously, one of the two is
always in active and the other in passive mode. The operator can request active mode on
the passive HMI at the press of a button.
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Significance
HMI wants to go online with an NCU
HMI is connecting to an NCU
HMI is disconnecting from an NCU
HMI must break connection with an NCU
Change operating focus from one NCU to the other
Operator control and monitoring/monitoring only
As an option, MCP can be switched over with the HMI
Operator can control and monitor
Operator can monitor (HMI header only)
Basic logic functions: PLC basic program solution line (P3 sl)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0