6F3B0253
3. I/O Application Precautions
(4)Countermeasures against leakage current
When a switch with an LED or sensor is used, the input sometimes cannot recognize that the switch is off due to the current leakage. In this case, install a bleeder resistor to reduce input impedance.
LE
Bleeder resistor
C
T1 input circuit
Select a bleeder resistor according to the following criteria:
(a)The voltage between the input terminals must be lower than the OFF voltage when the sensor is switched off.
(b)The current must be within the allowable range when the sensor is switched on.
(c)Calculate the wattage of the bleeder resistor by multiplying the current when the sensor is switched on times three.
Basic Hardware and Function 49
