Toshiba typeS, Instruction Manual

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Appendix C Notes on Applying the I/O Modules
6F8C1645
130
Pay sufficient attention to the P24 line so that is not cut.
(5) For the lamp load or the like, a rush current flows at output ON time.
You need to pay attention so that the output transistor is not destroyed due
to this rush current.
To restrict the rush current, it is useful to take measure where the resistor is
connected in parallel to the load, or a dark current remains flowing through
the lamp load with the resistor installed between the output terminals.
(6) If the inductive load is connected to an output module, a transient voltage
with a relatively large energy is generated at OFF time. This surge
voltage is absorbed with Diode D mentioned above to protect the transistor,
and if the external wiring is used for routing, this surge voltage may have
an adverse effect on other signal systems. To prevent this, install the
surge absorbing element in parallel to the inductive load as shown in Figure
C.3-4.
For the surge absorbing element, select a proper one as necessary for the
usage.
L
Transistor
output
module
• Freewheeling diode
(For voltage clamp)
Reverse withstand voltage: 3 times or more
relative to the supply voltage
Forward current: Greater than the load current
• Varistor
(For voltage clamp)
A varistor the rated voltage of which is more
than about twice the maximum supply voltage
• Snubber (CR) circuit
(For attenuation of
high frequency)
R: For 1 V coil voltage 0.5 to 1
C: 0.5
o
F to 1
o
F for 1 A coil current
(Nonpolar capacitor)
Figure.C.3-4
Connection of inductive load