Справочник Пользователя для Mitsubishi Electronics Q25HCPU

 

 

 

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MELSEC-Q

 

8   EMC AND LOW VOLTAGE DIRECTIVE 

 

 

8.2.5 Grounding 

There are the following two different grounding terminals. 

Use either grounding terminal in an earthed status. 

 

Protective grounding 

 

:  Maintains the safety of the PLC and improves the 

noise resistance. 

Functional grounding 

  :  Improves the noise resistance. 

 

8.2.6 External wiring 

(1)   24VDC external power supply  

For the MELSEC-Q series PLC 24VDC I/O modules and the intelligent function 

modules (special function modules) which require external supply power, use a 

model whose 24VDC circuit is intensively insulated from the hazardous voltage 

circuit. 

 

(2)   External devices 

When a device with a hazardous voltage circuit is externally connected to the 

PLC, use a model whose circuit section of the interface to the PLC is intensively 

insulated from the hazardous voltage circuit. 

 

(3)   Intensive insulation 

Intensive insulation refers to the insulation with the dielectric withstand voltage 

shown in Table 8.1. 

 

Table 8.1 : Intensive Insulation Withstand Voltage  

(Installation Category II, source : IEC664) 

 

Rated voltage of hazardous voltage area 

Surge withstand voltage (1.2/50  s) 

150VAC or below 

2500 V 

300VAC or below 

4000 V