Start-Up Behavior - Adam 821x Manual

Chapter 4 Deployment of the CPU 821xNET

Start-up behavior

Overview
Status after
CP boot-up
4-28
When the power supply is turned on, the CPU and the CP execute the
respective BIOS routine (hardware and driver initialization and memory
test).
While the CPU detects the installed modules on the backplane bus and
loads the application program, the CP starts the page frame administration
routine.
After app. 15s the CP waits for the synchronization request from the CPU.
In this condition data communication with the PLC is inhibited and it is only
enabled after synchronization has taken place.
The boot time of the CPU 821xNET including the CP amounts to app. 18s.
With every status change from STOP to RUN as well as from RUN to
STOP back to RUN, the CPU821xNET performs a cold-/warm reset. All
connections are cleared and reestablished after the CP has rebooted.
Three different reasons can cause these status change requests:
• Resynchronization of a CP by the SYNCHRON-HTBs of the CPU (warm
start) after it has already been synchronized,
• STOP/START-function of the configuration tool WinNCS (warm start),
• RESET_ALL (warm start).
ADAM 8000 Manual CPU 821x – Rev 1.1
CPU ADAM 821x