8.2.4 Parameter data transfer
Data communicaon with PROFINET is characterised by the simultaneous operaon of cyclic
and acyclic services in the network. As an oponal extension, the parameter data transfer
belongs to the acyclic services, which provides access to all device parameters.
•
The access to the device data depends on the PROFIdrive prole.
•
There is always only one parameter request in process (no pipelining).
•
No spontaneous messages are transferred.
•
There are only acyclic parameter requests.
In principle, a IO-Controller can always be used to request parameters from the IO-Device if
the IO-Device is in the DATA_EXCHANGE state.
Transmission direcons for acyclic data transfer
Write.res
Write.req
with data (parameter request)
with data (parameter response)
without data
without data
without data
without data
Read.req
Read.res (-)
Read.req
Read.res (+)Parameter response
Parameter request Parameter request
Parameter
processing
Parameter response
IO controller
IO device
1.
A "Write.req" is used to transmit the data set (DB47) as parameter request to the IO-
Device.
2.
"Write.res" is used to conrm to IO-Controller that the message was received.
3.
The IO-Controller uses "Read.req" to request the response of the IO-Device.
4.
The IO-Device responds with a "Read.res (-)" if processing is not yet completed.
5.
Aer parameter processing, the parameter request is completed by using "Read.res (+)" to
transmit the parameter response to the IO-Controller.
Telegram structure
Destr ScrAddr VLAN Type
0x0800
RPC NDR Read/Write Block Data FCS
6 bytes 6 bytes 4 bytes 4 bytes 80 bytes 64 bytes 64 bytes 0 .... 240 bytes 4 bytes
The iniator species the access to the "DB47" data set in the "Read/Write Block" eld. The
data wrien to this index or read from it contains a header and the parameter request or the
parameter response. The read data or the data to be wrien is contained in the "Data" eld.
Conguring the network
PROFINET
Parameter data transfer
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