6F3B0250
5. Operating System Overview
5.1 Operation modes
The T1/T1S has three basic operation modes, the RUN mode, the HALT mode and the ERROR mode. The T1/T1S also has the HOLD and
RUN: The RUN mode is a normal
In this mode, the T1/T1S reads external signals, executes the user program stored in the RAM, and outputs signals to the external devices according to the user program. It is in the RUN mode that the T1/T1S performs scans the user program logic, which is the basic operation of a PLC.
In case of the T1S, program changes and EEPROM write are possible while the T1S is in the RUN mode. Refer to section 6.9.
On the other hand, in case of the standard T1, program changes and EEPROM write are not possible in the RUN mode.
HALT: The HALT mode is a programming mode.
In this mode, user program execution is stopped and all outputs are switched off.
Program loading into the T1/T1S is possible only in the HALT mode.
For the standard T1, program changes and EEPROM write are possible only when the T1 is in the HALT mode.
ERROR: The ERROR mode is a
The T1/T1S enters the ERROR mode if internal trouble is detected by self- diagnosis. In this mode, program execution is stopped and all outputs are switched off. The cause of the
To exit from the ERROR mode, execute the Error Reset command from the programming tool, or cycle power off and then on again.
HOLD: The HOLD mode is provided mainly for checking the external I/O signals. In this mode, user program execution is stopped, with input and output updating is executed. It is therefore possible to suspend program execution while holding the output state. Moreover, a desired output state can be established by setting any data by using the programming tool.
Deferent from the normal RUN mode, the
82 T1/T1S User’s Manual
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