07.97 12 Functional Descriptions
12.28.4 Format of interface data blocks
Activation bits (PLC NC):
Each of the 32 bits represents a data transfer area, bit 0 = data transfer area 1. Data transfer
areas which have already been configured can be activated (bit x = 1) or deactivated (bit x =
0) with this signal. The activation signals are evaluated in every IPO cycle by the NC. Any
attempt to activate incorrectly configured areas is ignored without comment by the NC. The
NC indicates which data transfer areas are correctly configured in status bits (DL 2 to DR 3)
(bit 1 = 1 means: The data transfer area is correctly configured and can be activated).
Format of a data transfer area of "High-speed data channel type":
Job No. (acknowledgement from NC) DL
Control bits DR x
Value (bits 0 - 7) DL x+1
Value (bits 8 - 15) DR x+1
Value (bits 16 - 23) DL x+2
Value (bits 24 - 31) DR x+2
Control bits:
Error in NC
data write
operation
Error in NC
data read
operation
Synchronous
data
channel
New value for
NCK data
write
New value for
NCK data read
Error in NC data write/read operation
Set by NC if it has not been possible to read/write a value. Possible causes:
• Permissible value range exceeded.
• Drive not ready
New value for NC data read:
Indicates that the date value has been newly entered by the NCK. If the data transfer area has
been configured "with acknowledgement", then the NC enters data here only if this bit is not
set. "New value for NC data read" must in this case be reset by the PLC user after the data
have been ready so that the "writer" can enter new values again.
New value for NC data write:
Indicates that the data value has been newly entered by the PLC user. The NC accepts data
only if this bit is set. "New value for NC data write" must be set by the PLC user after the data
have been written so that the NC can read the new values.
© Siemens AG 1992 All Rights Reserved 6FC5197- AA50
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SINUMERIK 840C (IA)