Mitsubishi 13J851, Руководство пользователя

Страница: 36 / 270

23
DANGER
Create a safety circuit outside the PLC to ensure the whole
system will operate safely even if an external power failure
or a PLC failure occurs.
Otherwise, incorrect output or malfunction may cause an
accident.
(1) For an emergency stop circuit, protection circuit and
interlock circuit that is designed for incompatible actions
such as forward/reverse rotation or for damage
prevention such as the upper/lower limit setting in
positioning, any of them must be created outside the
PLC.
(2) When the PLC detects the following error conditions, it
stops the operation and turn off all the outputs.
The overcurrent protection device or overvoltage
protection device of the power supply module is
activated.
The PLC CPU detects an error such as a watchdog
timer error by the self-diagnostics function.
In the case of an error of a part such as an I/O control
part that cannot be detected by the PLC CPU, all the
outputs may turn on. In order to make all machines
operate safely in such a case, set up a fail-safe circuit
or a specific mechanism outside the PLC.
Refer to "LOADING AND INSTALLATION" in this
manual for example fail safe circuits.
(3) Depending on the failure of the output module’s relay or
transistor, the output status may remain ON or OFF
incorrectly. For output signals that may lead to a
serious accident, create an external monitoring circuit.
If load current more than the rating or overcurrent due
to a short circuit in the load has flowed in the output
module for a long time, it may cause a fire and
smoke. Provide an external safety device such as a
fuse.
Design a circuit so that the external power will be
supplied after power-up of the PLC.
Activating the external power supply prior to the PLC
may result in an accident due to incorrect output or
malfunction.
For the operation status of each station at a
communication error in data link, refer to the
respective data link manual.
The communication error may result in an accident
due to incorrect output or malfunction.