Safety Instructions
Safety Instructions
for design process
1.
Please install a protection circuit on the exterior of PLC
so that the
whole system may operate safely regardless of failures from
external power or PLC.
Any abnormal output or operation from PLC
may cause serious problems to safety in whole system.
(1) Install protection units on the exterior of PLC like an interlock circuit
that deals with opposite operations such as emergency stop,
protection circuit, and forward/reverse rotation or install an interlock
circuit that deals with high/low limit under its position controls.
(2) If any system error (watch-dog timer error, module installation error,
etc.) is detected during CPU operation in PLC, all output signals are
designed to be turned off and stopped for safety. However, there
are cases when output signals remain active due to device failures
in Relay and TR which can’t be detected. Thus, you are
recommended to install an addition circuit to monitor the output
status for those critical outputs which may cause significant
problems.
2.
Never overload more than rated current of output module nor
allow to have a short circuit
. Over current for a long period time may
cause a
fire .
3.
Never let the external power of the output circuit to be on earlier
than PLC power
, which may cause accidents from abnormal output or
operation.
4.
Please install interlock circuits in the sequence program for safe
operations in the system when exchange data with PLC or modify
operation modes using a
computer or other external equipments
Read specific instructions thoroughly when conducting control
operations with PLC.
Warning
