3. External Connection
34
DI-64T2-PCI, DO-64T2-PCI
Surge Protection
When connecting to digital outputs a load that may generate a voltage surge or current, for example an
inductive load such as a relay coil or incandescent lamp, suitable protection measures are required to
prevent damage to the output stage or malfunction owing to noise. The instantaneous interruption of
current flowing through a coil, including a relay, results in the sudden generation of a high-voltage
pulse. If the voltage exceeds the withstand voltage of the transistor, the transistor performance may be
degraded or the transistor may be damaged. To prevent this, be sure to connect a surge absorption
element when driving an inductive load including a relay coil. Examples of measures against voltage
surge are shown in Figure 3.10. below.
Figure 3.10. Samples of Voltage Surge Protection
The protection circuit must be installed less than 50 cm from the load and contact to provide
effective protection.
+5V
Output pin
Signal common
+5V
+5V
+5V
Examples of use of relay coil
Examples of use of lump
External power voltage < Zener diode voltage
Surge cu
rrent
prevention
resistor
Resistor
Diode
Relay
coil
Output pin
Signal common
Relay
coil
Zener diode
Output pin
Signal common
Output pin
Signal common
CAUTION
Содержание DI-64T2-PCI
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Страница 15: ...1 Before Using the Product 8 DI 64T2 PCI DO 64T2 PCI ...
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