Panasonic FP3 Technical Manual page 47

J Notes on limit switch and reed switch wiring
<LED - equipped limit switches>
The use of a bleeder resistor is recommended if the input is not turned OFF or if the LED of the limit switch is kept
ON due to leakage current from the limit switch.
The OFF voltage of the input is 2.4 V. Therefore, when the power supply voltage is 24 V, select an R value so that the
current will be greater than 2.4 V. The limit switch's leakage current I is:
I = 24–2.4
r
The impedance of the input terminal is 4.4 k .
The bleeder resistor R is: R ≦
The wattage W of the bleeder resistor is: W =
Actually, use a value that is 3 to 5 times the value of W.
<LED - equipped reed switch>
When an LED, such as an LED-equipped reed switch, is connected in series with an input point, make the voltage that
is applied to the FP I/O transmitter unit's input circuit greater than 20.4 V. Take particular care when connecting a
number of switches in series.
16 - input type FP I/O transmitter unit
+
0
24V
-
-
+
24V
R
r
LED- equipped
limit switch
r: internal resistor of the limit switch (k )
10.56
(kΩ)
4.4I–2.4
1 2 3 4 5 6
- -
+ + +
LED
Bleeder
resistor
LED- equipped
reed switch
(Power supply voltage) 2
R
7 8 9 A B
- - -
+ + +
20.4 V DC
or more
+
C D E F
RS
485
-
RS
- -
+ F.G.
485
3-2. Wiring
41