Is hardware interrupt update I/Os

1.11.3 Isochrone Updating of the Process Image Partition

With SFC 126 “SYNC_PI“ you can update a process image partition of the inputs synchronous to the clock. A user program linked to a DP cycle can use this SFC to consistently and synchronously update input data located in a process image partition. SFC 126 can be interrupted and can only be called in OBs 61, 62, 63 and 64.

With SFC 127 “SYNC_PO“ you can update a process image partition of the outputs synchronous to the clock. A user program linked to a DP cycle can use this SFC to synchronously update output data located in a process image partition and consistently transmit them to I/O devices. SFC 127 can be interrupted and can only be called in OBs 61, 62, 63 and 64.

To be able to update process image partitions synchronous to the clock, all input or output addresses of a slaves must be assigned to the same process image partition.

To ensure the consistency in a process image partition during each cycle, the following requirements must be fulfilled for each CPUs:

• CPU 412: number of slaves + number of bytes / 100 < 10

• CPU 414: number of slaves + number of bytes / 50 < 20

• CPU 416: number of slaves + number of bytes / 50 < 26

• CPU 417: number of slaves + number of bytes / 50 < 20

SFC 126 and 127 are documented in the corresponding online help and in the manual “System and Standard Functions”.