Toshiba V Series User Manual page 150

Chapter 3 Precautions for I/O Modules
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(5) If a capacitive load is connected, rush current will flow when output is charged to
ON.
At that time, necessary measures must be taken to protect the output transistor from
being destroyed by the rush current.
To limit the rush current there are two effective measures. One is to connect a
resistor to the load in series. The other is to apply dummy current to the load by
connecting a resistor between the output terminals.
(6) If an inductive load is connected, transient overvoltage will occur when the output is
changed to OFF.
This surge voltage will be absorbed into the diode D mentioned before so that the
transistor will be protected. However, if the output cable is installed closely to other signal
lines, the surge voltage may cause other problem. In this case, install a flywheel diode in
parallel with the inductive load (as near as possible to the load).
A suitable surge absorption element should be selected according to the application.
- Flywheel diode
(for voltage
clamping)
- Varistor
(for voltage
clamping)
- Snubber(CR)
voltage circuit
(for high frequency
attenuation)
Transistor
Output
module
Peak inverse voltage:
3 times the power supply
voltage or more
Forward current:
Load current or more
Rated voltage about
twice the maximum(peak)
power supply or more
R: 0.5 - 1 Ω per1V coil voltage
C: 0.5 - 1 µ F per 1A coil current
(Non-polar capacitor)
model 2000 Sequence Controller S2 User's Manual -Basic Hardware-
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