Setting Method For Writing To The Programmable Controller Cpu During Run - Mitsubishi MELSEC Q Series Reference Manual

2.5 Setting Method for Writing to the Programmable Controller CPU during RUN

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2 DATA COMMUNICATION USING THE MELSEC COMMUNICATION PROTOCOL
This section explains the setting for writing data from an external device to the running
programmable controller CPU via the C24/E71.
(1) Setting of the C24
Enable the "Online Change" setting of the transmission setting in the intelligent
function module switch setting screen using the programming tool.
For the switch setting, refer to the User's Manual (Basic) for the C24 used.
(2) Setting of the E71
Check the "Enable Write at RUN time" checkbox in the Ethernet operation setting
screen using the programming tool.
For the operation setting, refer to the User's Manual (Basic) for the E71 used.
(3) Setting on the programmable controller CPU side
Set the system protect switch to the "Enable write at programmable controller
CPU RUN time".
(In case of a QCPU (excluding Universal model QCPU), set the system
protection switch, SW1, to "OFF".)
POINT
When connecting a peripheral with the programmable controller CPU or connecting
an external device, such as a personal computer, with an intelligent function
module to modify data of a running programmable controller, configure an interlock
circuit in the program to ensure that the entire system will always operate safely.
For other forms of control (such as program modification or operating status
change) of a running programmable controller, read the relevant manuals carefully
and ensure that the operation is safe before proceeding.
Especially, when a remote programmable controller is controlled by an external
device, immediate action cannot be taken if a problem occurs in the programmable
controller due to a communication failure. To prevent this, configure an interlock
circuit in the sequence program, and determine corrective actions to be taken
between the external device and CPU module in case of a communication failure.
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