Program Execution According To The Ipo Model With Application Cycle > 1 - Siemens SIMATIC PROFINET Function Manual

Functions
5.7 Isochronous mode
5.7.7 Program execution according to the IPO model with application cycle > 1
Characteristics of the IPO-model with application cycle factor > 1
The IPO model with application cycle factor > 1 is an IPO model over multiple data cycles
T_DC. In this case, it is an IPO model with an output delayed by one application cycle
(OB6x). The input and processing take place in the same application clock cycle. Output is
performed at the start of the next application clock cycle, directly before the next input.
You call the "SYNC_PI" and "SYNC_PO" instructions in the execution window of the first
data cycle T_DC of the application clock cycle (only available there with application cycle
factor > 1.) The other user program execution in OB 6x then occurs after "SYNC_PO" and
extends into the next data cycle or over the following data cycles T_DC.
Figure 5-69 Program execution according to the IPO model with application cycle factor > 1
The figure shows the signals of the IPO model with application cycle factor = 2 over time
from the acquisition through the processing on the IO controller to the output of the process
values. STEP 7 calculates the delay time T
written output data is on its way on PROFINET IO.
The IPO model with application cycle factor > 1 is particularly ideal for large IO
infrastructures with a comprehensive user program in the OB6x. With this model, longer
calculation times are possible when executing the input data and obtaining the
corresponding output data.
With the IPO model with application cycle factor > 1, there is a constant execution time from
the "input terminal" to the "output terminal" of T
T + (2 x application cycle factor + 1) x T_DC + T
I
response time.
188
. During this time, the read input data and the
M
+ (application cycle factor + 1) x T_DC + T
I
can be guaranteed for the process
O
Function Manual, 09/2016, A5E03444486-AG
.
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PROFINET with STEP 7 V14