Siemens SIMATIC S7-1500 Function Manual page 26

Procedure
To create an isochronous connection between the I/O and user program, follow these steps:
1. Select the "IM 155-5 PN HF" in the network view of STEP 7. Change to the device view.
2. Insert an I/O module that can be operated isochronously (e.g. DI 16 x 24VDC HF).
3. Go to the "I/O addresses" area in the Inspector window of the selected I/O module.
Figure 5-1 Configuring isochronous mode on PROFINET IO
4. Make the following settings in the I/O addresses area:
– Select the "Isochronous mode" option.
– Select a process image partition, e.g., process image partition 1.
– Click the "Organization block" drop-down list. Click the "Add" button or select an
– Select the "Synchronous Cycle" OB. Confirm the selection with "OK".
Isochronous mode
Function Manual, 10/2018, A5E43884988-AA
5.1 Configuring isochronous mode for distributed I/O on PROFINET IO
already existing OB. A dialog box for selecting organization blocks opens.
In the case of automatic number assignment, OB 61 will be generated and opened.
In the Inspector window, you can continue directly with the setting of the application
cycle and delay time (Page 41) in the "Isochronous mode" area and start the
programming of the OB in the instruction section.
Configuring isochronous mode
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