Auditronics ALM-12d, Technical Manual, Page: 30 / 101

page 3 – 8
ALM-12d / Oct 2001
F A D E R S E C T I O N
Opto-isolated outputs also require an external voltage to function
properly. As an example, consider the connections to use the ON TALLY
LOGIC OUTPUT to drive an external LED to indicate the ON status of the
channel mapped to the logic port. Connect the +5V source to the plus (+)
terminal of a 5V LED (30 mA or less). Connect the minus (-) terminal of the
LED to the output’s plus (+) terminal (pin 24). Connect the input’s minus
(-) terminal (pin 12) back to the ground connection of the ex5V
supply. In this way, when the channel the port is mapped to goes on, the LED
will light.
External relays or lower or higher voltage LEDs may also be driven by
the outputs. Use current limiting resistors when necessary, do not exceed
24V for the external supply, and always use snubber diodes across con-
nected relay coils.