MM
™
-8802 User Manual
Page 34
http://aa.peavey.com copyright 2001 All Rights Reserved
Using Logic Ports with LEDs
Euro connector block
Equivalent DC Circuit
5 V Logic at “OUT” terminal
Ground terminal
Euro connector header
Rear panel
270
Two-wire termination
at connector block
Side view of two-wire con-
nection soldered to a resistor
and the pins of an LED
This example shows how you can connect an external LED to provide visual status of software-based controls. Using a low-
current, standard LED, you can use the TTL output port to directly activate the LED based on your desired software function.
The ground terminal in this case is pin 2 (GND) of the TTL output connector and is wired to the cathode side of the LED. The
OUT pin (Pin 1) is wired to a current limiting resistor, then to the anode side of the LED.
As before, it is advisable to use a high quality 2-conductor cable. A shield is not necessary, but the conductors should be at
least 20AWG. Heavier wire should be used as cable runs exceed 100’.
Unlike the CV port, care must be taken to ensure that the proper polarity is observed for making connections with the TTL
Logic Output ports. This is a DC output, and the polarity is positive, referenced to ground, at the OUT terminal. There is no
provision for adjusting the polarity within the software. For more information on this topic, please refer to the online help in
both the MWare
™
3.1.2 and X-Frame
™
88 software.