Scanning - Toshiba PROSEC T1-16S User Manual

5.3 Scanning

The flowchart below shows the basic internal operations performed by the T1-16S
from the time power is turned on through program execution. As the diagram shows,
executing a program consists of continuous scanning operations. One scan is a cycle
starting with the self-diagnosis and ending with the completion of peripheral support.
Scan
Power ON
Hardware check
Initial load
Register/device
initialization
Self-diagnosis
Mode
control
RUN mode
Register/device
initialization
Program check
I/O update
Timer update
User program
execution
Peripheral
support
5. Operating System Overview
HALT mode
At the first
scan
At the first
scan
Basic Hardware and Function
6F3B0253
Power-up
Initialization
(approx. 1 s)
Scan cycle
69