Yaskawa MP920 User's Manual Design - Manual (Page 77)

3.1 Operating Modes
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3.1 Operating Modes
This section explains the online operating mode and the offline stop mode, both of which indi-
cate the MP920 operating status.
Fig. 3.1 MP920 Operating Modes
3.1.1 Online Operating Mode
When the power for the MP920 is turned ON, the RDY and RUN indicators will light
(the ERR and ALM indicators will not light) and the Module will enter the online operating
mode. This means that the user program and I/O operations are being executed in the MP920
without any errors or failures. If an alarm does occur, such as for an I/O conversion error or a
user calculation error, the execution of the user program will not stop, and the online operat-
ing mode will be maintained. The ALM indicator lights to indicate the occurrence of an error.
For details on the error content and the action to be taken, see Chapter12 Troubleshooting.
3.1.2 Offline Stop Mode
The execution of the user program is stopped, and all outputs are reset (i.e., “0” is output for
all digital outputs). The RUN or RDY indicator will go OFF to indicate the status. Drawings
(DWG.H and DWG.L) are not executed in this status.
The Controller will be in the offline stop mode in the following four cases:
1. When the program memory has not been initialized
2. When a serious failure, such as watchdog timer error, has occurred
3. When a STOP operation has been performed from the MPE720
4. When the RUN/STOP switch has been set to OFF (STOP) and the power has been turned
ON
Note: The above cases 1, 2, and 3 apply when a user program error occurs,
or when there is hardware fault in the MP920. For details on the error
contents and the actions to be taken, see Chapter12 Troubleshooting.
RDY and RUN indicators lit
User program and I/O operation executing
RDY or RUN indicators not lit
User program stopped
Operating mode Online operating mode
Offline stop mode