Siemens SINUMERIK 840C - Manual (Page 621)

09.95 8 PLC Machine Data (PLC MD)
8.7 PLC MD bits for the user (user bits)
8.7 PLC MD bits for the user (user bits)
8000 to
8049
DW 0 -
DW 24
PLC MD
DB65
DW No.
Bit No.
7 6 5 4 3 2 1 0
Default value: 0
In addition to PLC MD words, PLC MD bits are also available to the user to do with as he sees
fit. The available bit area comprises 25 words (400 bits).
The PLC machine data enables the machine manufacturer to process program blocks, function
blocks or sections of a program conditionally on the basis of the bits set, and to allocate
machine-specific option bits. The user can then specify additional machine-specific values.
Sample application:
A user builds machines with different turrets, but wants to be able to provide a single program
for all machines. The turrets differ in the number of tool locations, e.g. turret 1 has 6, turret 2
has 8 locations.
The program for each type of turret (in this case a program block) is invoked via a
corresponding PLC machine data bit. In the program, the number of tool locations is specified
in PLC MD words.
OB 1
U MD1
JC PB
U MD2
JC PB
PB turret 1
PB turret 2
FB turret s
END OF SECTION
© Siemens AG 1992 All Rights Reserved 6FC5197- AA50 8–29
SINUMERIK 840C (IA)