12
•
Installation
2.4
External LED connection
Figure 2.3 External LED connectors for relay status indication
The PCI-7256 card has 16 LEDs on board to indicate the operation status of
the 16 relays. In addition, PCI-7256 also has 16 external LED connectors for
users’ applications. Utilizing external LEDs connecting with the JP3 and JP4,
users can have their relays status shown on chassis ,panel or other
apparatus. Only LED which have fordward voltage (V
f
) lower than 3V can
work normally. Each external LED connector has a current limiting resistor
(330
O
) connecting with +5V power, so it’s not necessary for user to add a
resistor to limit the current flow through LED.
The direction of the external LED’s connection is shown in Figure 2.3. Before
connect user’s LEDs on these connectors, make sure the LED is in the right
direction.
