Updating Process Image Partitions In The User Program - Siemens SIMATIC S7-1500 System Manual

Isochronous processing of the technology I/Os of interface X142
The operating modes timer DI, timer DQ, oversampling DI, oversampling DQ and
event/period measurement require isochronous processing in OB91 (MC Servo) or OB6x
(isochronous mode interrupt OBs). If you have configured one of those operating modes and
have not set isochronous processing, this will result in an error when compiling the hardware
configuration.
If you interconnect the technology I/Os with the technology object measuring input, output
cam or cam track, isochronous mode and assignment to the process image partition OB
servo are essential. The setting is made automatically as soon as you interconnect a
technology I/O with a corresponding technology object.
7.8.2

Updating process image partitions in the user program

Requirements
Alternatively, you can also use the following instructions to update process images:
● "UPDAT_PI" instruction
● "UPDAT_PO" instruction
You will find the instructions in STEP 7 in the "Instructions" task card under "Extended
instructions" in the "Process image" folder. You can call the instructions from any point in the
user program.
Requirements for updating process image partitions with the "UPDAT_PI" and "UPDAT_PO"
instructions:
● The process image partitions must not be assigned to any OB. This means the process
image partitions are not automatically updated.
Note
Update of PIP 0
PIP 0 (automatic update) cannot be updated with the "UPDAT_PI" and "UPDAT_PO"
instructions.
UPDAT_PI: Updates the process image partition of the inputs
With this instruction, you read the signal states from the input modules of the IO devices to
the process image partition of the inputs (PIPI).
UPDAT_PO: Updates the process image partition of the outputs
With this instruction, you transfer the process image partition of the outputs of the IO devices
to the output modules.
SIMATIC Drive Controller
System Manual, 11/2019, A5E46600094-AA
7.8 Process images and process image partitions
Configuring
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