Communication
89
Parameter handling in cyclic communication (DP)
In cyclic PROFIBUS DP communication, parameter data is
transferred in PPO message types 1, 2 and 5 (see Figure 8.). The
Parameter Identification part consists of eight bytes (see below).
The Request Label is used by the master when transmitting data
to the slave, while the Response Label is used by the slave as a
positive or negative acknowledgement. The tables below show the
Request/Response functions.
Request labels (from Master to Slave)
Request Function
Response labels
Ackn. (+) Ackn. (-)
0No task 0 –
1 Request parameter value 1, 2 7
2 Change parameter value (word) 1 7, 8
3 Change parameter value (double word) 2 7, 8
4 Request description element 3 7
5 Change description element 3 7, 8
6 Request parameter value (array) 4, 5 7, 8
7 Change parameter value (array word) 4 7, 8
8 Change parameter value (array double word) 5 7,8
9 Request number of array elements 6 7
ID IND VALUE
15 14131211109876543210
Request Label
Response Label
*Request Signal
Parameter Number (PNU)
Process Data
Parameter
Identification
*Not used (=0)
CW REF
(PD1, PD2...)
SW ACT
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