Parameter Data Transfer - Lenze i55AE125B Manual

9.6.10

Parameter data transfer

Data communication with PROFIBUS DP-V0 is characterised by cyclic diagnostics and cyclic
process data transfer. An optional service expansion is the acyclic parameter data transfer of
PROFIBUS DP-V1. This service does not impair the functionality of the standard services under
PROFIBUS DP-V0.
Details
PROFIBUS DP-V0 and PROFIBUS DP-V1 can be operated simultaneously in the same net-
•
work. This enables the step-by-step expansion or modification of a system.
The services of PROFIBUS DP-V1 can be used by the class 1 master (PLC) and the class 2 DP
•
master (diagnostics master, etc.).
Integration of the acyclic service into the fixed bus cycle depends on the corresponding
•
configuration of the class 1 master:
With configuration, a time slot is reserved.
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Without configuration, the acyclic service is appended when a class 2 DP master acycli-
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cally accesses a DP-V1 slave.
Product features
16 bits each for addressing the parameter index and subindex.
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Several parameter requests can be combined to one request (multi-parameter requests).
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Only one request is processed at a time (no pipelining).
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A request or response must fit into one data block (max. 240 bytes). Requests or responses
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cannot be split into several data blocks.
No spontaneous messages are transferred.
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There are only acyclic parameter requests.
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Profile-specific parameters can be read independently of the slave state.
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A class 1 DP master can always request parameters from a slave if the slave is in the "Data
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Exchange" state.
In addition to a class 1 DP master, a class 2 DP master can establish communication with a
•
slave:
Transmission directions for acyclic data transfer
Master
Parameter request
Parameter response
Procedure:
1. A "Write.req" is used to pass the data set (DB47) to the slave in the form of a parameter
request.
2. With "Write.res" the master receives the confirmation for the receipt of the message.
3. The master requests the response of the slave with "Read.req".
4. The slave responds with "Read.res (-)" if processing has not been completed yet.
5. After parameter processing, the parameter request is completed by transmitting the
parameter response to the master with "Read.res (+)".
DP-V1
Write.req
with data (parameter request)
Write.res
without data
Read.req
without data
Read.res (-)
without data
Read.req
without data
Read.res (+)
with data (parameter response)
Configuring the network
Parameter data transfer
Slave
Parameter request
Parameter
processing
Parameter response
PROFIBUS
303