User`s manual

2
When using the MELSEC-Q series serial communication module
[Design Precautions]
WARNING
● For the operation status of each station at communication error in each station, refer to the respective
manual for each station.
Incorrect output or malfunction due to a communication failure may result in an accident.
● When using the notification function, the pager receiver may not be contacted due to the frequency
transmission status from the system setup environment and error on the receiver side.
To ensure the safety of the programmable controller system, install a call circuit with a lamp display or
buzzer sound.
● When connecting a peripheral with the CPU module 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 program,
and determine corrective actions to be taken between the external device and CPU module in case of
a communication failure.
● Do not write any data to the "system area" of the buffer memory in the intelligent function module.
Also, do not use any "use prohibited" signals as an output signal from the programmable controller
CPU to the intelligent function module.
Doing so may cause malfunction of the programmable controller system.