Technical data

Table Of Contents
FBs for Cyclical Access to User Data according to the PNO
System Software for S7-300/400 System and Standard Functions - Volume 1/2
18-4
A5E00709327-01
18.4 Read a Part of the Inputs of a DP Standard
Slave/PROFINET IO Device with FB 22 "GETIO_PART"
Description
With the FB 22 "GETIO_PART" you consistently read a part of the process image
area belonging to a DP standard slave/PROFINET IO device. In doing so, FB 22
calls the SFC 81 "UBLKMOV".
Note
You must assign a process image partition for inputs to the OB in which FB 22
"GETIO_PART" is called. Furthermore, before calling FB 22 you must add the
associated DP standard slave or the associated PROFINET IO device to this
process image partition for inputs. If your CPU does not recognize any process
image partitions or you want to call FB 22 in OB 1, you must add the associated
DP standard slave or the associated PROFINET IO device to this process image
partition for inputs before calling FB 22.
You use the OFFSET and LEN parameters to specify the portion of the process
image area to be read for the components addressed by means of their ID.
If there was no error during the data transmission, ERROR receives the value
FALSE, and the data that have been read are entered in the target area indicated
by INPUTS.
If there was an error during the data transmission, ERROR receives the value
TRUE, and STATUS receives the SFC 81 error information "UBLKMOV".
If the target area (INPUTS parameter) is smaller than LEN, then as many bytes as
INPUTS can accept are transferred. ERROR receives the value FALSE. If the
target area is greater than LEN, then the first LEN bytes in the target area are
written. ERROR receives the value FALSE.
Note
The FB 22 "GETIO_PART" does not check the process image for inputs for
delimiters between data belonging to different PROFIBUS DP or PROFINET IO
components. Because of this, you yourself must make sure that the process image
area specified by means of OFFSET and LEN belongs to one component. Reading
of data for more than one component cannot be guaranteed for future systems and
compromises the transferability to systems from other manufacturers.