Mitsubishi Electric MELSEC-L Series LD40PD01 User Manual page 222

4.
Display the setting window for the refresh parameters and set the values as follows.
[Project window]  [Parameter]  [Network Parameter]  [Ethernet / CC IE / MELSECNET] 
5.
Write the set parameters to the CPU module on the master station. Then reset the CPU module or power off and on the
programmable controller.
[Online]  [Write to PLC]
RESET
or Power OFF
13 PROGRAMMING
220
13.3 When the Module Is Connected to a Head Module
button
ON