Hitachi LQZ700, User Manual

Page: 38 / 47

4 USER GUIDE
4-5
4.1.3 Operation procedure at occurrence of an error
When a SYS SW module error occurs, the operation procedure is as follows.
System Operation
Start
When a running-system unit error occurs, the
SYS SW module detects the error in the following
cases.
z The PCs OK output of the LPU is turned off.
z
The PI/O OK output is turned off by an
application program.
When detecting a self-system unit error, the SYS
SW module of the running system turns off the
STOP/RUN, BUSY OUT, and PI/O OK outputs
and turns on the “ERR” LED.
The SYS SW module of the standby system
outputs BUSY OUT, confirms that BUSY IN is not
turned on again, and turns on the execution
command STOP/RUN of the self-system LPU.
Thus, this SYS SW module controls the system
as the running system.
When detecting that the BUSY IN has been
turned off, the SYS SW module of the standby
system turns on the BUSY OUT output to cause
the self-system to go to the running system.