05.91
11 Data Transfer PLC/NC/COM (DB 36)
11.1 Introduction
11
Data Transfer PLC/NC/COM (DB 36)
11.1
Introduction
Data transfer can be initiated by the NC or PLC.
Data transfer on NC initiative
In the case of NC initiative the transfer is triggered by commands in cycle language CL 800; all
cells in the PLC can be read and written. The data are stored in the NC in R parameters and
transferred to the PLC from R parameters.
The PLC user program is generally not affected by data transfer on NC initiative; the PLC
operating system assumes responsibility for the transfer operation on the PLC side.
Data transfer on NC initiative
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NC
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PLC
Command
Data type
Data
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Data
Cycles
PLC data
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PLC
operating
system
SINUMERIK
SIEMENS
a a
Read/
write PLC
data
(data driver)
Display
program
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Data
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Data
Note:
In the event of indirect addressing via the NC/PLC data channel (NC initiative), the PLC user
program must make data addresses available (can be necessary, for example, with specially
programmed functions in the UMS).
© Siemens AG 1991 All Rights Reserved 6ZB5 410-0HE02
11–1
SINUMERIK 880 (PJ)