Central User Db (Db 59) - Siemens SINUMERIK 880 SW 6 Planning Manual

05.91
DATA TRANSFER ASSIGNED
1 signal: 0 1 transition of DATA TRANSFER REQUESTED
0 signal: 1 0 transition of DATA TRANSFER ENDED
Example of application:
Interlocks in the PLC program during the request and execution phase of data transfer.
DATA TRANSFER ENDED
1 signal: Job completed without errors.
0 signal: After 1 signal, if DATA TRANSFER REQUESTED is 0.
16.4

Central user DB (DB 59)

A central DB 59 with a length of 128 words is set up in the link RAM (not cancelled) with the
"FORMAT USER M." softkey in the startup mode.
DB 59 is a user DB to which both PLCs have access with equal priority; in other words, both
PLCs can access (read and write) the same DW.
The PLC user programmer is responsible for determining the access of the PLCs to DB 59.
DB 59 must also be cancelled by the PLC user.
Synchronization for data access between the PLCs (if necessary) and a write interlock must
also be implemented in the PLC user program.
To prevent collisions on the link bus, the hardware prevents two PLCs accessing DB 59 at
exactly the same time.
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Siemens AG 1991 All Rights Reserved
SINUMERIK 880 (PJ)
16 PLC/PLC Interface (DB 50 ... DB 53, DB 59)
16.3.3 Interface signals for active PLCs (DB 51, DB 53)
6ZB5 410-0HE02
DB m, bit 3
DB m, bit 4
16–9