Bradley Smoker PLC-5 Block-Transfers in Processor Input Interrupts PIIs, C40.CU, Destination S51

Using Processor Input Interrupts 18-3

As shown in the following figure, the PII program must:

•count 100 tablets per group

•set an output at the 100th tablet

•reset the counter for the next group

				C4:0.CU
				U
			CTU
		COUNT UP			CU
		Counter		C4:0
		Preset		100	DN
		Accum
C4:0					Output
	DN
Output				C4:0
				RES
			CLR
			CLEAR
			Destination		S:51

The output image bit remains set until the next count.

Block-Transfers in Processor Input Interrupts (PIIs)

If the controller runs a PII that contains block-transfer instructions, the controller performs these block-transfers immediately on completing any block-transfers currently in the active buffer, ahead of block-transfer requests waiting in the queue.

You can program “immediate” block-transfers to a local I/O chassis using the PII program (i.e., the PII is invoked and the block-transfer occurs immediately). The controller executes the block-transfer immediately, completes the remaining rungs in the PII, then resumes execution of the ladder program.

You can use the PII for a block-transfer to remote I/O. Remote block-transfer instructions in a PII cause the controller to resume executing user programs, while waiting for the block-transfer to complete. If you want the PII to run to completion before returning to your main logic program, include a UID and UIE instruction pair in your PII program file. Place the block-transfer instruction inside of a UID/UIE pair.

Publication 1785-UM012D-EN-P - July 2005