User`s manual

7-21
(4) Notes for long-distance wiring and by-pass wiring
In the AC input module, when the cables to external device are very long or wiring along with
power lines is made, the input module might be turned ON in spite of the OFF command in the
input device, due to leakage current and inducement by floating capacity among cables.
Countermeasure 1: Connect a bleeder resistance and a CR surge killer in parallel with the input
module to reduce the composite impedance of the input module.
The smaller the R value, the more effective.
However, when R becomes small, power
consumption ( ) increases. Therefore, note the
R's watt value.
C: 0.033 to 0.33 µF
(Pressure resistance of over 250 VAC)
R: 47 to 120 ohm
Countermeasure 2: Change the input power supply to DC (Use DC input module)
In general, the direct current signals are little affected by floating capacity and
inducement.
Countermeasure 3: Close circuit by making use of the b contact.
When the b contact is used to make a close circuit at OFF, very little induced
voltage is generated.
Note: Do not wire the input signal line near and in parallel with power lines of a motor and an inverter.
V
2
R
Power line, etc.
IN
COM
Input module
Input module
Input module
R
R
C
IN
COM
Input module