Siemens SINUMERIK 840D sl Function Manual page 121

Power-up condition:
To prevent the previously selected MCP from being activated again when the NCU is
restarted, input parameter MCP1BusAdr must be set to 255 (address of 1st MCP)
andMCP1Stop to TRUE (deactivate 1st MCP) when FB1 is called in OB100.
Enabling commands:
When one MCP is switched over to another, any active feedrate or axis enabling signals may
be transferred at the same time.
Note
The override switch of the new MCP is immediately effective following an MCP switchover.
The keys actuated at the time of the switchover continue to take effect. If no MCP is installed
on the newly selected PCU, then it will not be possible to cancel the key functions from the
PCU. Measures for situations of this type must be implemented in the PLC user program.
Operating mode switchover
The operating mode switchover is not mandatory. It can be enabled or disabled via the
FB101/DB101 variable aktiv_enable. Assignment in the declaration table:
TRUE: Operating mode switchover is effective
FALSE: Operating mode switchover is not effective, no FB102 call
Error messages
If disturbances occur (e.g. interface signal failure) while the program is running,
corresponding alarms/error messages are transferred to data block DB2. 6 alarms are
implemented:
1. Error in HMI bus address, HMI bus type
2. No confirmation HMI 1 offline
3. HMI 1 is not going offline
4. No confirmation HMI 2 offline
5. HMI 2 is not going offline
6. Requesting HMI is not going online
and an error message: Sign-of-life monitoring error
If the default settings in FB101 are not changed, the alarms start at
DB2.DBX188.0 (1st alarm) and end at
DB2.DBX188.(6th alarm)
With variable:
DBX_Byte_alarm, the byte value for the 6 alarms can be changed from the default setting of
188. With variable:
DBX_Byte_report, the byte value of the operational message can be changed from the
default setting of 192.
Extended Functions
Function Manual, 01/2008, 6FC5397-1BP10-3BA0
Several Operator Panels on Several NCUs, Distributed Systems (B3)
2.2 Several operator panel fronts and NCUs with control unit management option
121