ProSoft Technology InRAX MVI46-PDPS, Руководство пользователя

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MVI46-PDPS ♦ SLC Platform Reference
Profibus DP Slave Communication Module
Page 50 of 72 ProSoft Technology, Inc.
April 30, 2008
Master/Slave Communication Phases
The communication between the Master and the Slaves takes place in the
following phases:
ƒ Parameterization and configuration phase
ƒ Usable data transfer phase
Before a DP Slave can be integrated into the usable data transfer phase, the
parameterization and configuration phase runs a device identification test that
verifies that the planned configuration matches the actual device configuration for
each slave in the PROFIBUS network. The test verifies that:
ƒ
the device is actually there
ƒ it is the right type of device
ƒ the address, which is set on the device, matches the station address on the
bus
ƒ the formats, telegram length information, and bus parameters are correct
and
ƒ the number of configured inputs and outputs is correct.
5.2.4 Backplane Data Transfer
The MVI46-PDPS module communicates directly over the SLC backplane. All
data for the module is contained in the module's M1 file. Data is moved between
the module and the SLC processor across the backplane using the module's M-
files. The SLC scan rate and the communication load on the module determine
the update frequency of the M-files. The COP instruction can be used to move
data between user data files and the module's M1 file.
The following illustration shows the data transfer method used to move data
between the SLC processor, the MVI46-PDPS module and the PDPS network.
User File
User File
User File M0
M1
PROFIBUS
Data
Input Data
Output
Data
Input Data
Output
Data
Ladder
Logic
M-Files
PROFIBUS
Slave
PROFIBUS
Master
M1 Status
Data