Siemens SINUMERIK 880 GA2, Planning Manual

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18 Decoding Lists for M Signals (DB 80 ... DB 95) 05.91
18.3 Structure of decoding lists
18.3 Structure of decoding lists
Size of decoding lists
A maximum of 64 M functions with extended address can be decoded per NC channel. Each
M function with extended address sets a pair of bits, i.e. a static signal and the associated
dynamic signal, in DB 30.
The assignment of the M functions with extended address and the pairs of bits in DB 30 is
determined in the decoding lists. Each entry for an M function assigns three data words in the
relevant DB.
DBs 80 to 95 can be created only with certain lengths as indicated in the following table. Fields
that are not required (always at the end of the decoding lists; see below) must be preassigned
with 0.
Permissible decoding list sizes
Number of M functions
Number of DWs in
decoding lists
1 M function
2 M functions
4 M functions
8 M functions
16 M functions
32 M functions
64 M functions
6
6
12
24
48
96
192
Decoding list structure
Each entry in the decoding lists comprises three data words.
The extended address for the M function is specified in the first data word and the M address
is stated in the second data word. The third data word determines the pair of bits in DB 30 that
is to be influenced by the M function. The DR stipulates the number of the static bit in the
specified data word. The dynamic bit is addressed automatically by the PLC operating system.
Structure of decoding lists
Definition of
DW No. in
DB 30
0-63
(KY)
Definition of
bit No. in
DB 30
0-7
(KY)
static bit
DW 0 DW 1 DL 2 DR 2
DW 3 DW 4 DL 5 DR 5
DW 189 DW 190 DL 191 DR 191
Extended M
address M address
0-999
(KF)
0-99
(KF)
a a a a a a a a a a a a a a a a a a a a
a a a a a a a a a a a a a a a a a a a a
a a a a a a a a a a a a a a a a a a a a
a a a a a a a a a a a a a a a a a a a a
a a a a a a a a a a a a a a a a a a a a
a a a a a a a a a a a a a a a a a a a a
1st M function
a a a a a a a a a a a a a a a a a a a a
a a a a a a a a a a a a a a a a a a a a
a a a a a a a a a a a a a a a a a a a a
a a a a a a a a a a a a a a a a a a a a
a a a a a a a a a a a a a a a a a a a a
a a a a a a a a a a a a a a a a a a a a
a a a a a a a a a a a a a a a a a a a a
2nd M function
a a a a a a a a a a a a a a a a a a a a
a a a a a a a a a a a a a a a a a a a a
a a a a a a a a a a a a a a a a a a a a
a a a a a a a a a a a a a a a a a a a a
a a a a a a a a a a a a a a a a a a a a
a a a a a a a a a a a a a a a a a a a a
a a a a a a a a a a a a a a a a a a a a
64th M function
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SINUMERIK 880 (PJ)