User`s manual

6
When using the MELSEC-L series serial communication module
[Design Precautions]
[Design Precautions]
[Installation 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 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 CPU module to the
intelligent function module.
Doing so may cause malfunction of the programmable controller system.
CAUTION
● Do not install the control lines or communication cables together with the main circuit lines or power
cables.
Keep a distance of 100mm or more between them.
Failure to do so may result in malfunction due to noise.
WARNING
● Shut off the external power supply (all phases) used in the system before mounting or removing a
module.
Failure to do so may result in electric shock or cause the module to fail or malfunction.