Toshiba T2N - Manual (Page 115)

2.INTERNAL OPERATIONS
102 PROSEC T2N
The operation of each mode and the mode transition condition are shown below.
HALT : External all output OFF, user program execution and I/O
processing halted. In HALT mode, the mode control is
performed periodically (every 50ms). Peripheral support and
self-diagostics are performed for the idle time. This is the mode
for user to edit/change user program.
RUN : After initial load (when neccesary), user data initialization, I/O
module setting up, user program check and scan mode
decisions, the T2N goes into RUN mode.
Mode control, batch I/O, timer update and user program
execution are repeatedly performed in RUN mode. This
operation is called scan control.
There are two kinds of scanning system, the floating scan
repeats program execution continuously and the constant
scan repeats program execution constantly according to user
specified time. The selection is called scan mode selection.
Scan control is explained in detail in 2.4 and 3.
RUN-F : This is the forced run mode. It differ from the above RUN mode
in that scan control begins even if the allocated I/O modules
are not actually mounted. (If other modules are mounted
instead, the mode does not run.)
Otherwise the action is the same as the above RUN mode.
HOLD : This is the scan hold mode. Only the batch I/O is run, but the
timer update and the user program execution are halted. The
scan mode continues previous scan mode.
The I/O test can be done by the data monitor and data set
function.
DEBUG : This is the program debugging mode. Program bebugging
functions (single step execution, single rung execution, run N
scan execution, break point set up, prohibition of external I/O
update, etc.) can be used this mode.
Refer to 5.6 for details of debug function.
ERROR : This is the error mode. The T2N goes to this ERROR mode
when an error is detected in the self diagnostic checks,
operation cannot be resumed by the prescribed retry action
and operation cannot be continued correctly. In ERROR
mode, all output are OFF and the error reset command from
the programmer is effective (the error reset command will
recover from ERROR mode to HALT mode). Refer to 5.
RAS Functions for details of diagnostic.