LSIS XGK-CPUU - Page 177

Chapter 14 Troubleshooting
13-11
Phenomena Causes Measures
Off
Response
time of
load is
long
abnormally.
y Over current when Off
[In case of running the inductive load of
current such as solenoid (time constant L/R is
large) directly by transistor output.
y As the current flows through diode
when transistor output OFF, more than 1
second may be delayed according to the
load.
y Insert the magnetic contactor that time
constant is small and run the load by the
contact as below.
Output
transistoris
destroyed.
Inrush current of incandescent light
When light ON, more than 10 times of inrush
current may flow.
y To control the inrush current, it need to
flow 1/3 ~ 1/5 dark current of rated current of
incandescent light.
Output
Load
E
Current when off
Output
E1
Output
Load
Output
E
R
Output
E
R
Sink type transistor output
Source type transistor output