[DESIGN PRECAUTIONS]
!
DANGER
Using communication status information, create an interlock circuit on the programs so that the
system will operate safely. Failure to do so may cause an accident due to incorrect output or
malfunction.
When an error occurs, all outputs in the MELSEC-ST system are turned OFF. (At default)
However, I/O operation in the case of the following errors can be selected for the head module
and each slice module. Configure the settings to ensure safety of the entire system.
(1) Communication error (Refer to the MELSEC-ST PROFIBUS-DP Head Module User’s
Manual.)
(2) Slice module failure
The output status in the case of an error can be set to Clear/Hold/Preset with a user
parameter of each slice module. (For the setting, refer to each slice module manual.)
Since the parameter is set to Clear by default, outputs are turned OFF if an error occurs.
This parameter setting can be changed to Hold or Preset if necessary. (Refer to Section
3.3.2.)