User`s manual

7-22
(5) Surge current of the AC input module
There is surge current in the AC input module: JW-203N/211NA, when turning ON the input.
The surge current of the AC input module is determined by constants (R, C) of the input circuit
inside the module, power supply voltage at ON input, phase, power supply current capacity and
wiring impedance. The surge current stated in the AC input module specifications is the worst
value for the case of the ON input at the maximum impressed voltage and at the peak phase.
If, in certain input device, contact points are affected (adhered etc.) by the surge current, the surge
current should be reduced by connecting a limit resistance Rs outside the module as shown below.
The following limit resistances Rs can be connected outside the module:
For 100 VAC input module, less than 2 k ohm (over 2 W rate electricity)
For 200 VAC input module, less than 4 k ohm (over 2 W rate electricity)
Reference
- When a limit resistance of 2 k ohm (or 4 k ohm) is connected for the 100 VAC (or 200 VAC) input
module, the surge current becomes less than 80 mA at the peak ON.
Note: If a resistance bigger than the above value is connected, the input ON/OFF levels and the
response times cannot be guaranteed.
(6) Countermeasure in case of connection of induced load to input signal
If the induced load is connected to the input signal, in order to absorb the noise, connect a surge
killer near the load for the AC circuit; and a diode, for the DC circuit, as shown below.
Surge killer: R, C
C: 0.033 to 0.33 mF
(Resistance voltage of over 250 VAC)
R: 47 to 120 ohm
Diode:
Peak inverse voltage (V
RM
) should be more than 3
times bigger than the load voltage, and the average
rectification current should be bigger than load
current.
AC input module
OFF ON→
Limit
resistance
Rs
R
C
Surge current
IN
COM
AC input module
L load
Surge killer
For AC power supply
IN
COM
DC input module
L load
For DC power supply