GE 90-30/20/Micro manual Instruction Timing, Execution Time Description

Appendix

A

Instruction Timing

The Series 90-30, 90-20, and Micro PLCs support many different functions and function blocks. This appendix contains tables showing the memory size in bytes and the execution time in microseconds for each function. Memory size is the number of bytes required by the function in a ladder diagram application program.

Two execution times are shown for each function:

Execution Time

Description

Enabled	Time required to execute the function or function block when power
	flows into and out of the function. Typically, best-case times are
	when the data used by the block is contained in user RAM (word-
	oriented memory) and not in the ISCP cache memory (discrete memory).
Disabled	Time required to execute the function when power flows into the
	function or function block; however, it is in an inactive state, as
	when a timer is held in the reset state.

Note

Timers and counters are updated each time they are encountered in the logic, timers by the amount of time consumed by the last sweep and counters by one count.

GFK-0467K A-1