[DESIGN PRECAUTIONS]
!
DANGER
Create an interlock circuit on the program so that the system will operate safety based on the
communication status information. Failure to so may cause an accident due to an erroneous
output or malfunction.
When an error occurs, all outputs are turned OFF in the MELSEC-ST system (at default).
However, I/O operations of the head module and respective slice modules can be selected for
the errors described below.
Select the status for each module for the entire system safety.
(1) Communication error (Head Module User’s Manual)
(2) Slice module error
The output status for the case of an error can be set to Clear, Hold or Preset with a
command parameter of each slice module. (For setting availability, refer to the manual for
each slice module.)
Since the parameter is defaulted to Clear, outputs will be turned off if an error occurs.
This parameter setting can be changed to Hold or Preset when the system safety is more
ensured by holding or presetting the output.