Setting The Application Cycle And Delay Time - Siemens SIMATIC PROFINET Function Manual

Functions
5.7 Isochronous mode
Programming isochronous mode
The user program must be set up accordingly in order to operate your plant in isochronous
mode. To do this, you must create an isochronous mode interrupt OB (OB 6x) in an
I/O module (see above). You access the isochronous I/O via a process image partition, i.e.,
the addresses of isochronous modules must be in a process image partition. You have to
program accesses to the isochronous IO with the instructions SYNC_PI and SYNC_PO in
the isochronous mode interrupt OB.
With an application cycle = 1 you call the SYNC_PI instruction at the start of the isochronous
mode interrupt OB, provided you have selected the automatic setting for the delay time. You
call the instruction SYNC_PO at the end of the OB 6x.
With an application cycle > 1 you first call the SYNC_PO instruction at the start of the
isochronous mode interrupt OB, then the SYNC_PI instruction and subsequently the actual
user program.
5.7.9

Setting the application cycle and delay time

Requirement
● You have created an isochronous mode configuration in STEP 7.
● You have created an isochronous mode interrupt OB.
● The isochronous mode interrupt OB is open.
Setting the application cycle and delay time
To set the application cycle for your isochronous mode application, follow these steps:
1. Open the "Properties" dialog associated with the relevant isochronous mode interrupt OB.
2. In the area navigation, click the "Isochronous mode" group .
3. Set the application cycle in "Application cycle (ms)". Open the drop-down list box and
select the application cycle. The drop-down list box offers multiples of the PROFINET
send cycle clock as possible values for the application cycle. The PROFINET send cycle
clock is set to 2 ms in the following figure.
Figure 5-72
192
Setting the application cycle
PROFINET with STEP 7 V14
Function Manual, 09/2016, A5E03444486-AG