Siemens SINUMERIK 840Di Manual page 224

7 PROFIBUS DP Communication
7.3 SIMATIC S7 project
Consistency
7-224
The default setting with regard to the consistency of the I/O data is whole
length.
This setting results in:
S
Direct accesses from the PLC user program (e.g. byte, word or double word)
to this address range are not admitted by the PLC operating system.
S
Accesses to this address range must be carried out using the system func-
tions SFC 14 and SFC 15.
S
The system functions SFC 14 and SFC 15 guarantee consistent reading/
writing of the data of an axis.
Note
The terms isochronous, clock-synchronous, and equidistant (same length) are
used as synonyms in various documents.
Function parameters
In dialog box: DP slave properties –> Encoder tab, the function parameters are
entered (see Fig. 7-4 with sample values for the individual parameters).
DP slave properties
General Configuration Clock synchronization
Encoder 1 Encoder 2
Encoder type: Encoder type:
TTL TTL
Resolution: Resolution:
6000
Unipolar spindle
1st Axis
Shutdown ramp [ms]:
Shutdown delay [s]:
OK
Fig. 7-4 Dialog: DP slave properties, tab card: Encoder
Encoder
Encoder 3
Encoder type:
SSI
Parity
Resolution:
6000
MsgLength:
Encoding:
Binary
Baudrate:
187.5 kbps
2nd Axis 3rd Axis
1 Tolerable sign-of-life errors:
0 Reserved bits for fine resolution:
611U conformant mode
 Siemens AG, 2003. All rights reserved
SINUMERIK 840Di Manual (HBI) – 06.03 Edition
06.03
Encoder 4
Encoder type:
SSI
Parity
Resolution:
2048 2048
21 MsgLength: 21
Encoding
Gray
Baudrate:
187.5 kbps
4th Axis
5
11
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