TheDCP31isprovidedwithfourexternalswitchinputsasstandard(eightoptional).Theop-
tional eightinputsarelocatedontheadd-onterminalbase.Wire theexternalswitchinputs
acrossthestandardandadd-onterminalbases.
 Handling Precautions
• The external switch inputs on the DCP31 have built-in power 
supplies (open voltage 12Vdc). Be sure to use no-voltage con-
tacts for external contacts.
• Use no-voltage contacts such as gold contacts whose small cur-
rent can be switched ON/OFF. On some relay contacts, the small 
current cannot be switched ON/OFF. Use no-voltage contacts 
having a sufficient minimum switching capability with respect to 
the contact current and open voltage of the DCP31.
• When using a semiconductor (e.g. open-collector) as a no-
voltage contact, use a semiconductor whose contact terminal 
voltages at contact ON are 3V max., and whose leakage current 
at contact OFF is 0.1mA.
• External switch inputs on the DCP31, DCP32, and SDC40 series 
can be connected in parallel.  
When connecting in parallel with other controllers, thoroughly 
check the conditions of the other controller before configuring 
the control system.
25
23
24
21
22
RSW1
RSW2
RSW3
RSW4
Contact
Contact
Contact
Contact
COM
45
43
44
41
42
48
46
47
RSW5
RSW6
RSW7
RSW8
RSW10
RSW11
RSW12
RSW9
Contact
Contact
Contact
Contact
Contact
Contact
Contact
Contact
4-15
Chapter 4. WIRING
4 - 12  Connecting External Switch (RSW) Input