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4 Communications via PROFIBUS–DP
4.3 Parameter area (PKW area)
Transferring
traversing blocks
Rules for the
task/response
processing
4-124
For SIMODRIVE POSMO A the traversing blocks are saved in parame-
ters which means that they can only be read and changed via the PKW
mechanism.
Reader's note
The parameters for the traversing blocks are described in Chapter
5.3.2.
When mapping the traversing blocks to the parameters, the parameter
number defines the block components (position, velocity, etc.) and the
sub–parameter number of the traversing block number.
Example: P81.17 ––> position, parameter 81 with traversing block 17
Addressing in the PKW mechanism:
S
The parameter ID (PKE) addresses the block components.
S
The sub–index (IND) addresses the traversing block number
This means that a complete set can only be read or changed one after
the other via the individual components.
Additionally:
1. Machine data is mapped to the parameters
2. Additional parameters (e.g. P947, P953, etc.) are possible from the
PROFIBUS Guidelines.
The following rules apply for the task/response processing:
1. A task or a response can always only be referred to one parameter.
2. The master must repeat a task until it has received the appropriate
response from the slave (clock cycle: 10 ms).
3. The slave provides the response until the master has formulated a
new task.
4. The master recognize the response to a task which it issued:
– by evaluating the response ID
– by evaluating the parameter number (PNU)
– if required, by evaluating the parameter index (IND)
5. For response telegrams that contain parameter values, the slave,
for this cyclic repeat process, always responds with the updated
value.
This involves all responses to the tasks "request parameter value"
and "request parameter value (array)".
SIMODRIVE POSMO A User Manual (POS1) – 08/2013 Edition
E Siemens AG 2013 All Rights Reserved
02.99
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