Siemens SINUMERIK 840D sl Function Manual page 126

Several Operator Panels on Several NCUs, Distributed Systems (B3)
Several operator panel fronts and NCUs with control unit management option
Mixed mode
Definition:
The term "mixed mode" refers to a state in which a conventional OP without control unit
switchover function is connected to the first HMI interface on the NCU. The control unit
switchover then operates exclusively on the 2nd HMI interface.
Parameter "MMC_mixed_mode" (variable in FB101/DB101) can be set to switch the
operating mode from pure HMI operation to mixed mode by entering the following settings.
When FB101 is called, this must be assigned:
TRUE Mixed mode is effective. Control unit switchover operates on the 2nd interface
FALSE Mixed mode is not effective. Control unit switchover operates on both interfaces
Supplementary conditions:
● A machine control panel (MCP) must not be configured for the first HMI interface. The
● To allow the second HMI interface to be assigned active mode status, it is possible to
Server mode
Once a server has occupied the HMI interface of an NCU, it cannot be suppressed by any
other device.
Processing operating authorization for servers
Three server-related program branches for handling HMI requests are implemented in the
control unit switchover program:
1. Request for relinquishing operating focus
2. Request for setting operating focus
3. Relinquish operating focus
Each branch checks/processes the first and second HMI interfaces.
The requests are positively acknowledged if no switchover disabling commands are active.
The "Relinquish operating focus" includes deactivation of the relevant machine control panel.
See also diagrams in Section "Examples/Graphic representation of function sequences".
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first HMI interface is always assigned active mode status in mixed operation.
assign active mode status to both online interfaces in mixed operation. However, certain
supplementary conditions apply.
WARNING
When data are input from both control units simultaneously, there is a risk that
inconsistent data will be transferred to the control.
Function Manual, 03/2009, 6FC5397-1BP10-4BA0
Extended Functions