Siemens SINUMERIK Commissioning Manual page 123

Configuration
The current task number is transferred to the PLC in a data block section that can be
specified as a string in the display MD 9032: HMI_MONITOR as follows:
DBxx.DBByy with:
xx is the number of a data block
yy is the byte number of the 1st byte of the transfer area (word limit)
The transfer area is 8 bytes long, the transfer is made in the 1st byte. Bytes 2 to 8 are
reserved.
Note
Check that the specified area is not already occupied by input bytes, output bytes or flag
bytes. The block number and the byte area are not checked.
Updating
The task number in the first byte is updated for:
● At every task change by the HMI
● When the connection is changed to a different NC in M:N
For the duration of indeterminate states (e.g. during changeover to another NC in M:N),
special value 255 is transferred as the task number.
Range of values
The task number can assume values from 0 to 95, including the operating areas configured
by the user.
As a result, all visible tasks of the main menu (0 to 31) and the hidden child tasks (32 to 95)
are displayed.
HMI Advanced (IM4)
Commissioning Manual, 03/2009, 6FC5397-0DP10-3BA0
4.2 Transferring the actual task number of the HMI to the PLC
Programming PLC Functions
117