Assign Process Image Partitions To An Ob; Update Process Image Partitions In The User Program - Siemens Simatic ET200pro Operating Instruction

Configuring
4.2 Configuring the CPU
4.2.3.2

Assign process image partitions to an OB

Update process image partition
You can assign a process image partition to an OB. In this case, the process image partition
is automatically updated.
The process image partition of the inputs (PIPI) is always read in/updated before the
processing of the associated OB. The process image partition of the outputs (PIPQ) is
always output at the end of the OB.
The following figure illustrates the updating of a process image partition.
Figure 4-8
4.2.3.3

Update process image partitions in the user program

Requirements
As an alternative to automatic updating and updating via assignment to an OB, you can use
the "UPDAT_PI" or "UPDAT_PO" instruction at the start or end of the OB assigned in each
case to update the process image. These instructions are available in STEP 7 on the
"Instructions" task card under "Extended instructions" and may be called from any point in
the program.
Requirements for updating process image partitions with the "UPDAT_PI" and "UPDAT_PO"
instructions:
● The process image partitions cannot be assigned to any OB, i.e. they cannot be
automatically updated.
● PIP 0 (automatic update) can likewise not be updated with the "UPDAT_PI" and
"UPDAT_PO" instructions.
UPDAT_PI: Update process image partition of the inputs
With this instruction you read the signal states from the input modules into the process
image partition of the inputs (PIPI).
UPDAT_PO: Update process image partition of the outputs
With this instruction you transmit the process image partition of the outputs to the output
modules.
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Update process image partitions
CPU 1516pro-2 PN (6ES7516-2PN00-0AB0)
Operating Instructions, 09/2016, A5E35873416-AA