Siemens SINUMERIK 840D sl Function Manual page 1334

Detailed description
2.7 Structure and functions of the basic program
The readin disable in the channel is reset once the user has reset all the bits output by this
channel and thus acknowledged them.
The output of an M function decoded in the list as a highspeed auxiliary function does not
result in a readin disable.
The figure below shows the structure of the M decoding according to list:
Figure 2-14 M decoding acc. to list
Activation of the function
The number of groups to be evaluated/decoded is indicated in the basic program parameter
"ListMDecGrp" when FB 1 is called in OB 100 (see also FB 1 description). M decoding is
activated if this value is between 1 and 16. Before the function is activated, the decoding list
DB75 must be transferred to the PLC followed by a restart.
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Basic logic functions: PLC basic program solution line (P3 sl)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0