11  TROUBLESHOOTING
11.4  Examples of Troubles with the I/O Module
111
11
■Action
Before turning on or off the external power supply, check that the rise time of the external power supply is 10ms or more. 
Then, install a switch (SW1) to the primary side of the external power supply.
When installing the switch to the secondary side, connect a capacitor and resistor, and increase the rise time (10ms or more).
 • Sink output
 • Source output
R1: Several tens of ohms
Power capacity  (External power supply current
*1
)
2
  Resistance value  (3 to 5)
*2
C1: Several hundreds of microfarads 50V
(Example)
R1 = 40, C1 = 300F
Time constant is calculated as shown below.
C1  R1 = 300  10
- 6
  40
= 12  10
-3
s
= 12ms
*1 For the current consumption of the external power supply for the module, refer to the manuals.
*2 Select the power capacity of resistor to be 3 to 5 times as large as the actual power consumption.
SW1
Output module
Secondary sidePrimary side 
External power supply
Y0
SW
R1
C1
CTL+
COM-
Load
24VDC
Y0
SW
R1
C1
CTL-
COM+
Load
24VDC