18.4
PiStAr64/PiStAr256
18.4.1
Description of PiStAr64/256
Object name (type + number) and family
Type + number: FB 2604/ FB 2617
Family: AdvLibPI
Area of application for PiStAr64/256
The block is used for the following applications:
● Reading a parameter of data type String or Array of Byte (
OctStr
) by means of acyclic data
in combination with PiDr64/256 driver block.
How it works
The block initiates reading of the data record via driver block PiDr64/256 on request. A
parameter of the elementary data type that is addressed via the block inputs is read from the
data record and made available at the block output.
Note
The PiDr64/256block is capable of simultaneous processing of several read jobs in successive
order only. If read jobs are started by several blocks, the blocks are executed based on the call
sequence. It is advisable to configure the program so that simultaneous initiation of multiple
jobs is safely prevented.
Note
The data records are read by means of acyclic services. Since it is not possible to execute more
than 8 acyclic services simultaneously per Profibus segment, you are responsible for
preventing the simultaneous start of more than 8 jobs. For this reason, you are strongly advised
not to use cyclic read services to read acyclic data. (Each instance of a PiDr64/256 block cannot
process more than one read or write job simultaneously.)
Configuration
Use the CFC editor to install the block in a cyclic interrupt OB (OB30 to OB38). Interconnect the
in/out structure
AcyclData
of the PiEl64/256 block to the output of the same name at the
PiDr64/256 block.
Driver blocks
18.4 PiStAr64/PiStAr256
SITRANS Library for PCS 7
828
Function Manual, 05/2019, A5E35351976-11
Summary of Contents for SITRANS PCS 7
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