Siemens SINUMERIK 840Di Function Manual page 967

The figure below shows the structure of the M decoding according to list:
Fig. 2-13
Structure of decoding list
There must be an entry in decoding list DB 75 for every group of M functions to be decoded.
A maximum of 16 groups can be created.
16 bits are available in each group in the list of decoded signals.
The assignment between the M function with extended address and the bit to be set in the
signal list is specified via the first and last M functions in the decoding list.
The bit address is generated correspondingly from the first M function ("MFirstAdr") to the
last M function ("MLastAdr") from bit 0 up to maximum bit 15 for each group.
Each entry in the decoding lists consists of 3 parameters, each of which is assigned to a
group.
The source file for the decoding list (MDECLIST:AWL) is supplied with the basic program.
Power Line Basic PLC Program (P3)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
M decoding acc. to list
2.7 Structure and functions of the basic program
Detailed description
2-55