Mitsubishi Electronics Q25HCPU Electronic Accessory User Manual


 
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SAFETY PRECAUTIONS
(Read these precautions before using.)
When using Mitsubishi equipment, thoroughly read this manual and the associated manuals introduced in
this manual. Also pay careful attention to safety and handle the module properly.
These SAFETY PRECAUTIONS classify the safety precautions into two categories: "DANGER" and
"CAUTION".
!
DANGER
CAUTION
!
Indicates that incorrect handling may cause hazardous conditions,
resulting in death or severe injury.
Indicates that incorrect handling may cause hazardous conditions,
resulting in medium or slight personal injury or physical damage.
Depending on circumstances, procedures indicated by
!
CAUTION may also be linked to serious
results.
In any case, it is important to follow the directions for usage.
Store this manual in a safe place so that you can take it out and read it whenever necessary. Always
forward it to the end user.
[DESIGN PRECAUTIONS]
!
DANGER
Install a safety circuit external to the PLC that keeps the entire system safe even when there
are problems with the external power supply or the PLC module. Otherwise, trouble could result
from erroneous output or erroneous operation.
(1) Outside the PLC, construct mechanical damage preventing interlock circuits such as
emergency stop, protective circuits, positioning upper and lower limits switches and
interlocking forward/reverse operations.
(2) When the PLC detects the following problems, it will stop calculation and turn off all output
in the case of (a). In the case of (b), it will stop calculation and hold or turn off all output
according to the parameter setting.
Note that the AnS series module will turn off the output in either of cases (a) and (b).
(a) The power supply module has over current protection equipment and over voltage
protection equipment.
(b) The PLC CPUs self-diagnosis functions, such as the watch dog timer error, detect
problems.
In addition, all output will be turned on when there are problems that the PLC CPU cannot
detect, such as in the I/O controller. Build a fail safe circuit exterior to the PLC that will make
sure the equipment operates safely at such times. See section 9.1 of this manual for
example fail safe circuits.
(3) Output could be left on or off when there is trouble in the outputs module relay or transistor.
So build an external monitoring circuit that will monitor any single outputs that could cause
serious trouble.