Mitsubishi 13J851, Руководство пользователя

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(6) Avoid mounting the base unit in proximity to vibration sources such as
large magnetic contractors and no-fuse circuit breakers; mount these on a
separate panel or at a distance.
(7) In order to avoid the effects of radiated noise and heat, provide the
clearances indicated below between the PLC and devices that generate
noise or heat (contactors and relays).
•
Required clearance in front of .........................100mm or more (3.94inch)
(more than 150mm (5.91inch) for duplex systems)
•
Required clearance on the right and left of......50mm or more (1.97inch)
100mm (3.94inch)
or more
Contactor, and
relay, etc.
50mm (1.97inch)
or more
50mm (1.97inch)
or more
4.2 Fail-Safe Circuit Concept
When the PLC is powered ON and then OFF, improper outputs may be generated
temporarily depending on the delay time and start-up time differences between the
PLC power supply and the external power supply for the control target (especially,
DC).
For example, if the external power supply for the control target is powered ON and
then the PLC is powered ON, the DC output module may generate incorrect
outputs temporarily upon the PLC power-ON. Therefore, it is required to build the
circuit that energizes the PLC by priority.
The external power failure or PLC failure may lead to the system error.
In order to eliminate the possibility of the system error and ensure fail-safe
operation, build the following circuit outside the PLC: emergency circuit, protection
circuit and interlock circuit, as they could cause machine damages and accidents
due to the abovementioned failures.
An example of system design, which is based on fail-safe concept, is provided on
the next page.