Mitsubishi Electric MELSEC-Q Series User Manual page 5

[DESIGN PRECAUTIONS]
● When controlling a running programmable controller from a peripheral
connected to the CPU module or from a personal computer connected to a
special function module, configure an interlock circuit in the sequence
program to ensure that the entire system will always operate safely.
For program modification and operating status change, read relevant manuals
carefully and ensure the safety before operation.
Especially, in the case of a control from an external device to a remote
programmable controller, immediate action cannot be taken for a problem on
the programmable controller due to a communication failure.
To prevent this, configure an interlock circuit in the sequence program, and
determine corrective actions to be taken between the external device and
CPU module in case of a communication failure.
● When setting up the system, do not allow any empty slot on the base unit.
If any slot is left empty, be sure to use a blank cover (A1SG60) or a dummy
module (A1SG62) for it.
Otherwise, internal parts of the module may be flied in the short circuit test or
when an overcurrent or overvoltage is accidentally applied to the external I/O
section.
● Do not install the control lines or communication cables together with the main
circuit lines or power cables.
Keep a distance of 100mm (3.9inches) or more between them.
Failure to do so may result in malfunction due to noise.
● When a device such as a lamp, heater, or solenoid valve is controlled through
an output module, a large current (approximately ten times greater than
normal) may flow when the output is turned from off to on. Take measures
such as replacing the module with one having a sufficient current rating.
● After the CPU module is powered on or is reset, the time taken to enter the
RUN status varies depending on the system configuration, parameter
settings, and/or program size.
Design circuits so that the entire system will always operate safely, regardless
of the time.
WARNING
CAUTION
A-3