GE 90-30/20/Micro manual Input Scan

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time. In order to maintain accuracy, the actual start of sweep is recorded in 100 microsecond increments. Each timer has a remainder field which contains the number of 100 microsecond increments that have occurred since the last time the timer value was incremented.

Input Scan

Scanning of inputs occurs during the input scan portion of the sweep, just prior to the logic solution. During this part of the sweep, all Model 30 input modules are scanned and their data stored in %I (discrete inputs) or %AI (analog inputs) memory, as appropriate. Any global data input received by a Genius Communications Module, an Enhanced Genius Communications Module, or a Genius Bus Controller is stored in %G memory.

Modules are scanned in ascending reference address order, starting with the Genius Communications Module, then discrete input modules, and finally analog input modules.

If the CPU is in STOP mode and the CPU is configured to not scan I/O in STOP mode, the input scan is skipped.

GFK-0467K Chapter 2 System Operation 2-7