Bradley Smoker PLC-5 Monitoring Controller Input Interrupts, This PII Field Stores Address

18-6Using Processor Input Interrupts

Monitoring Controller Input Interrupts

Use the controller status screen in your programming software to monitor PIIs.

		Status File
This PII Field	Stores	Address
Events since last	Displays the number of PII events (the input conditions that caused the interrupt)	S:52
interrupt	since the last interrupt.
PII changed bits	Displays the bit transitions that caused the interrupt. You can use this information	S:51
	to condition other rungs in your ladder program.
	If one of these bits is already set (i.e., a previous interrupt set the bit), the controller
	sets a minor fault (S:10/2) to indicate a possible PII overlap. If you want to monitor
	this overlap, make sure the last rung in your PII program clears this return mask in
	the status file.
Last scan time	Displays the current or last scan time through the PII.	S:55
Max observed scan	Displays the maximum value that was displayed in the last	S:56
time	scan field.
Word not in local	This box is checked if the input word number specified is not on the local rack or if	S:10/11
rack	there is not an input module in the slot addressed.
No command blocks	This box is checked if no command blocks exist to get the PII. You can use the	S:10/13
	controller’s internal counter or bit transition to execute the PII.
User routine overlap	This box is checked if a set condition exists in the PII return mask or changed bits	S:10/12
	(possibly set by a previous interrupt) before completing the currently executing PII
	routine. PII changed bits are retentive. It may be necessary to place a MOV

instruction on the last rung in the PII file. Move 0 in S:51 to reset the PII bits before finishing the PII file. If this is not done, a PII overlap bit will be set on that status page, causing this minor fault.

Use S:51/0-15 within the PII file because these bits are:

•mapped from the actual input module being used for the PII

•retentive

For the PII routine to execute properly, do not use the addresses of the input module’s bits within the PII routine.

Publication 1785-UM012D-EN-P - July 2005