xxi
Safety Precautions
3
• The NSJ Controller will turn OFF all outputs when its self-diagnosis func-
tion detects any error or when a severe failure alarm (FALS) instruction is
executed. Unexpected operation, however, may still occur for errors in the
I/O control section, errors in I/O memory, and other errors that cannot be
detected by the self-diagnosis function. As a countermeasure for all such
errors, external safety measures must be provided to ensure safety in the
system.
• The NSJ Controller outputs may remain ON or OFF due to deposition or
burning of the output relays or destruction of the output transistors. As a
countermeasure for such problems, external safety measures must be
provided to ensure safety in the system.
!WARNING
Do not attempt to disassemble, repair, or modify the NSJ Controller.
Doing so may impair the safety functions.
!WARNING
Confirm safety before transferring data files stored in the file memory (Mem-
ory Card or EM file memory) to the I/O area (CIO) of the Controller Section
using a Programming Device. Otherwise, the devices connected to Output
Units may malfunction regardless of the operation mode of the Controller Sec-
tion.
!WARNING
Fail-safe measures must be taken by the customer to ensure safety in the
event of incorrect, missing, or abnormal signals caused by broken signal lines,
momentary power interruptions, or other causes. Serious accidents may
result from abnormal operation if proper measures are not provided.
!WARNING
The NSJ Controller refreshes I/O even when the program is stopped (i.e.,
even in PROGRAM mode). Confirm safety thoroughly in advance before
changing the status of any part of memory allocated to Output Units, Special
I/O Units, or CPU Bus Units. Any changes to the data allocated to any Unit
may result in unexpected operation of the loads connected to the Unit. Any of
the following operations may result in changes to memory status.
• Transferring I/O memory data to the Controller Section from a Program-
ming Device.
• Changing present values in memory from a Programming Device.
• Force-setting/-resetting bits from a Programming Device.
• Transferring I/O memory files from a Memory Card or EM file memory to
the Controller Section.
• Transferring I/O memory from a host computer or from another node on a
network.
!WARNING
Always ensure that the personnel in charge confirm that installation, inspec-
tion, and maintenance were properly performed for the NSJ Controller. “Per-
sonnel in charge” refers to individuals qualified and responsible for ensuring
safety during machine design, installation, operation, maintenance, and dis-
posal.
!WARNING
Ensure that installation and post-installation checks are performed by person-
nel in charge who possess a thorough understanding of the machinery to be
installed.
