P3: Basic PLC Program for SINUMERIK 840D sl
13.8 Structure and functions of the basic program
Basic Functions
886
Function Manual, 09/2011, 6FC5397-0BP40-2BA0
13.8.9
M decoding acc. to list
Description of functions
When the M decoding according to list function is activated via the GP parameter of FB1 "ListMDecGrp" (number
of M groups for decoding), up to 256 M functions with extended address can be decoded by the basic program.
The assignment of the M function with extended address and the bit to be set in the signal list is defined in the
decoding list. The signals are grouped for this purpose.
The signal list contains 16 groups with 16 bits each as decoded signals.
There is only one decoding list and one signal list i.e. this is a cross-channel function.
The M functions are decoded. Once they are entered in the decoding list, then the associated bit in the signal list
is set.
When the bit is set in the signal list, the readin disable in the associated NCK channel is set simultaneously by
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:
