User manual

Publication 1760-UM001A-EN-P
Installation 2-9
Two-wire proximity sensors have a residual off-state leakage current. If this residual
current is too high, the input may indicate the input is ON when the device is
actually off.
Use inputs I7 and I8 for these types of input devices. If more inputs are required,
use a bleeder resistor or bleeder capacitor for inputs I1 through I6, and I9 through
I12.
Increasing the Input Current
Use the following input circuit for electrical noise immunity and when using
two-wire proximity switches:
When using a 100 nF capacitor, the drop-off time of the input increases by 66.6 ms
at 60 Hz (80 ms at 50 Hz). Also, a capacitor increases the amount of current seen
by the input device. Do not use a bleeder capacitor in conjunction with reed
switches.
To limit the current to 400 mA, connect a 1K
Ω resistor in series upstream from
the circuit as shown.
.
L1
1A
L2
L1 L2 I2 I3 I4 I5 I6 I7 I8I1
120/240V ac
50/60Hz
Inputs x 120/240V ac
30K Ω, 5W resistor; or
100 nF, 275V ac capacitor
L1
1A
L2
L1 L2 I2 I3 I4 I5 I6 I7 I8I1
120/240V ac
50/60Hz
Inputs x 120/240V ac
100 nF, 275V ac capacitor
1K
Ω
0.25W
resistor