Mitsubishi FX3UC SERIES User Manual page 149

FX Series Programmable Controllers
3UC
User's Manual - Hardware Edition
2. In the case of input device with built-in parallel resistance
Use a device having a parallel resistance, Rp, of 15kΩ or more.
If the resistance is less than 15kΩ, connect a bleeder resistance, Rb, obtained by the following formula as
shown in the following figure.
4Rp
≤
(kΩ)
Rb
15-Rp
• Examples of wiring (Dedicated to sink input types only)
PLC
COM
• Examples of wiring (Common to both sink and source input types)
Sink input wiring
X
PLC
COM
3. In the case of 2-wire proximity switch
Use a two-wire proximity switch whose leakage current, I , is 1.5mA or less when the switch is off.
When the current is 1.5mA or more, connect a bleeder resistance, Rb, determined by the following formula as
shown in the following figure.
6
≤
(kΩ)
Rb
I -1.5
• Examples of wiring (Dedicated to sink input types only)
X
PLC
COM
• Examples of wiring (Common to both sink and source input types)
Sink input wiring
PLC
COM
+24V
Bleeder
Rb
resistance
X
15kΩ or
Rp
more
15kΩ or
more
Bleeder
Rb
resistance
Rp
24V DC
Fuse
+24V
Bleeder
2-wire
Rb
resistance
proximity
sensor
I
2-wire
proximity
I
sensor
X
Bleeder
Rb
resistance
24V DC
Fuse
5 Input Specifications and External wiring
Source input wiring
X
Bleeder
PLC
Rb
resistance
COM
24V DC Fuse
Source input wiring
I
X
Bleeder
PLC
Rb
resistance
COM
24V DC Fuse
5.2 24V DC Input Type
15kΩ or
more
Rp
2-wire
proximity
sensor
143
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