Panasonic fp2/fp2sh - Page 150

FP2/FP2SHInstallation and Wiring
4 − 20
4.3 Wiring Input and Output
Connection of LED-equipped Limit Switch
With the LED-equipped limit switch, if the input of the PLC is not turned off or if the LED
of the limit switch is kept on because of the leakage current, the connection of a bleeder
resistor is recommended, as shown below.
The off voltage of the input is 2.5V, therefore when the power supply voltage is 24V, select R
so that
the current will be greater than I =
The resistance R of the bleeder resistor is: R ≦
The wattage W of the resistor is: W=
In
the
actual
selection,
use
a
value
that
is
3
to
5
times
the
value
of
W
.
24 - 2.5
r
Internal circuit
DC
Input unit
COM
Input
terminal
LED-equipped
limit switch
Bleeder
resistor
R
r
r: Internal resistor of limit switch (kΩ)
R: Bleeder resistor (kΩ)
7.5
3 × I−2.5
(Power supply voltage)
2
R
(kΩ)
Using 16-point type DC input unit (FP2−X16D2)
(Off voltage: 2.5V, Input impedance: 3kΩ)