Scanning - Toshiba PROSEC T1 User Manual

5.3 Scanning

The flowchart below shows the basic internal operations performed by the T1/T1S 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
CTi Automation - Phone: 800.894.0412 - Fax: 208.368.0415 - Web: www.ctiautomation.net - Email: info@ctiautomation.net
Power ON
Hardware check
Initial load
Register/device
initialization
Self-diagnosis
Mode
control
RUN mode
Register/device
At the first
scan
initialization
At the first
Program check
scan
I/O update
Timer update
User program
execution
Peripheral
support
5. Operating System Overview
HALT mode
Basic Hardware and Function
6F3B0250
Power-up
initialization
(approx. 1 s)
Scan cycle
87