Obsidean_VM/01-Documentation/SIEMENS & WINCC/TIA Portal/Assign process image-process image partition.md

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Assign process image/process image partition

Introduction

A process image offers the advantage that you can access a consistent image of process signals during cyclic program execution. For S7-1500, you can choose between "Update automatically" and "PIP 1" to max. "PIP 31".

Assigning addresses to the automatically updating process image area

You define the process image during address assignment (inspector window, "I/O addresses" area). The following setting should be selected if the addresses of a module are to lie in the process image area that is updated automatically by the system in each program cycle:

For comparison: For S7-300/400 modules, this setting is called "OB1 process image".

If the addresses should not lie in the process image area, select "None" as the process image.

Assigning an address to a process image partition

You define the process image partition during address assignment (inspector window, "I/O addresses" area). The process image partition is updated either by the user with the help of instructions or automatically by the system by connection to an OB.

Connecting a process image partition to an OB

You also connect a process image partition to an OB in the I/O addresses area ("Organization block" parameter).

For OBs of the type "Cyclic Interrupt", for example, the next free process image partition is assigned automatically; this can be changed, however. After the OB has been started, the assigned process image partition of inputs is updated by the system. At the end of the OB, the outputs of the assigned process image partition are written to the I/O outputs by the system. The process image partitions are excluded from the automatic update.

Example for the coupling of the process image partition 2 (PIP 2) to a cyclic interrupt:

Exception: process image partitions of isochronous mode interrupt OBs are not updated by the system, even though they are connected to an OB (OB 61 to OB 64).

The assigned process image or process image partition is displayed in the properties of the assigned OB (cannot be changed).

Updating a process image partition in the user program

You can update each process image partition in the user program with special instructions. Use "UPDAT_PI" for the process image partition input and "UPDAT_PO" for the process image partition output.

Requirement

• You are in the device view.
• The module or submodule has an I/O address.

Procedure

To change the preset process image range, proceed as follows:

1. In the device view, select the module whose start address you want to set.
2. In the inspector window, click on the "I/O Addresses" area under "Properties".
3. Under "Process image," select the desired process image.