Siemens SIMATIC S7-1500 Function Manual page 43

Configuring isochronous mode
5.6 Setting the application cycle and delay time
Setting the delay time
The delay time is the time between the start of the send clock and the start of the
isochronous mode interrupt OB. STEP 7 sets the delay time automatically to the start of the
execution window by default. As a result, the isochronous mode update of the process image
partition automatically falls within the execution window of the application cycle. Note that
you must call the "SYNC_PI" and "SYNC_PO" instructions in the execution window of the
application cycle.
You can also set the delay time manually. A shorter delay time enables you to increase the
processing time for your user program in the isochronous mode interrupt OB.
To set the delay time for your isochronous mode application, follow these steps:
1. Open the "Properties" dialog of the isochronous mode interrupt OB under consideration.
2. In the area navigation, click the "Isochronous mode" group .
3. Clear the "Automatic setting" check box.
4. Enter your desired delay time in "Delay time (ms)".
Figure 5-14
42
Setting the delay time
Isochronous mode
Function Manual, 10/2018, A5E43884988-AA