Siemens SINUMERIK 840D sl Function Manual page 209

If an MCP has been configured for the online operator panels, the MCP of the active
operator panel is switched on. The MCP of the passive operator panel is deactivated, i.e.
only one MCP is active at a time on an NCU.
Four signals are provided in the HMI-PLC interface for each of the two online operator
panels. These signals are used by the PLC to control operating mode changeovers.
Table 2- 6 Signals (x = 1, 2: 1st or 2nd HMI-PLC interface)
HMI-PLC interface
MMCx_ACTIVE_REQ
MMCx_ACTIVE_PERM
MMCx_ACTIVE_CHANGED
MMCx_CHANGE_DENIED
An example of how operating modes can be switched over is described in the following
sequence.
Two operator panels online to one NCU, MMC_1 in active operating mode, MMC_2 in
passive operating mode, operator requests active operating mode on MMC_2.
Signal state for this case:
MMC_1
MMC1_ACTIVE_REQ
MMC1_ACTIVE_PERM
MMC1_ACTIVE_CHANGED
MMC1_CHANGE_DENIED
MMC_2 requests active operating mode and sets MMC_2_AKTIVE_REQ = TRUE.
The PLC acknowledges the request from MMC_2 with MMC_2_ACTIVE_REQ = FALSE.
The PLC then requests MMC_1 to change to passive operating mode with
MMC1_ACTIVE_PERM = FALSE.
Extended Functions
Function Manual, 03/2009, 6FC5397-1BP10-4BA0
Several Operator Panels on Several NCUs, Distributed Systems (B3)
Value Meaning
FALSE → HMI to PLC: Passive operator panel requests active operating mode
TRUE
TRUE → PLC to HMI: Request received
FALSE
FALSE → PLC to HMI: Passive operator panel can change to active operating
TRUE mode
TRUE → PLC to HMI: Active operator panel must change to passive operating
FALSE mode
FALSE → HMI to PLC: Operator panel has completed changeover from passive
TRUE to active mode
TRUE → HMI to PLC: Operator panel has completed changeover from active to
FALSE passive mode
FALSE → HMI to PLC or PLC to HMI depending on interface: Operating mode
TRUE cannot be changed due to uninterruptible processes on active operator
panel.
TRUE → HMI to PLC or PLC to HMI depending on interface: Acknowledgement
FALSE of MMCx_CHANGE_DENIED(FALSE->TRUE)
VALUE
FALSE
TRUE
TRUE
FALSE MMC2_CHANGE_DENIED
MMC_2
MMC2_ACTIVE_REQ
MMC2_ACTIVE_PERM
MMC2_ACTIVE_CHANGED
Examples
Value
FALSE
FALSE
FALSE
FALSE
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