Chapter 4 Installing Hardware
4-15
4.1.6 Wiring Digital Input Terminals on CPU Modules
4.1.6.1 Direct Current Power Supply (24 VDC)
When the digital input signal is DC input, there are two DC input types, Sinking and Sourcing. See the
definition below.
Sink = The current flows into the X end.
Source = The current flows from the X end.
4.1.6.2 Relay Types
• Sinking
S/S
X0
I/O
Internal circuit
24VDC
+
Inter nal circuit
Sourcing
S/S
X0
I/O
Internal circuit
24VDC
+
Internal circuit