24Vdc Single-End Input Circuit And Wiring For Sink/Source Input - FATEK FBs Series User Manual

6.3 24VDC Single-End Input Circuit and Wiring for SINK/SOURCE Input

The 24VDC single-end digital input circuits of FB
the similar circuit structures but with different response speeds. To save input terminals, the circuit of single-end input is
implemented by connecting one end of all input points (photo coupler) inside the PLC to the same internal common
point labeled as S/S. The other end of each input circuit is connected to corresponding terminals such as X0, X1, X2,
etc. The S/S common terminal and N single-end inputs comprise of N digital inputs (i.e., only N+1 terminals are used
for N terminals). Therefore, we call this type of input structure the single-end input. The user also needs to do the same
thing when making the connection of external digital input devices. Namely, the one end of all input devices (e.g.,
buttons, switches) are connected together and called the external common wire, while the other ends of input circuits
are connected to the input terminals X0, X1, X2, etc., of PLC. Then finish it by connecting the external common wiring
and internal common terminal S/S to the positive/negative terminals of the 24VDC power. When connect the internal
common terminal S/S to 24V+(positive) and the external common wire to 24V－ (negative), then the circuit serve as
SINK input. On the contrary, while exchange the wiring of the above internal and external common will serve as a
SOURCE input. The above wiring schemes can illustrated below:
Wiring of single-end common SINK input
External
外部
Power
電源
FB
S
|
PLC
Wiring of single-end common SOURCE input
External
外部
Power
電源
FB
S
|
PLC
External Common Wiring
外部共線
24VDC
24V-
24V+
24VDC
(not available in
(擴充模組無)
expansion modules)
External Common Wiring
外部共線
24VDC
24V+ 24V-
24VDC
(擴充模組無)
(not available in
expansion modules)
-PLC are available for high, medium and low speed. They all have
S
NPN
Sensor
S/S X0 X1
Internal
內部共點
R1 R1
Common
端子
Terminal
R2 R2
X0 X1
PNP
Sensor
S/S X0 X1
Internal
內部共點
R1
Common R1
端子
Terminal
R2 R2
X0 X1
H 6 - 3
Input devices
輸入元件
X2 X3
R1
R1
R2 R2
X3
X2
Input Circuit
輸入元件
X2 X3
R1 R1
R2 R2
X3
X2
Low speed
R1:5.6K
R2:1KΩ
Middle speed
R1:3.3KΩ
R2:1.2KΩ