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Soundweb
TM
Control Inputs
Used to connect switches or potentiometers to the 9088. These eight inputs are internally
‘pulled up’ to +5V DC via a 4.7kOhm resistor, so no external voltage source is needed.
Four common (ground) connections are provided (all connected together internally). A
47kOhm log potentiometer connected between one input and common will allow
parameters to be controlled linearly. Alternatively, a switch may be connected between
an input and common, or a multiway switch may be connected to several inputs with the
wiper connected to common.
Logic Outputs
Used to connect the 9088 to ‘tally’ indicator LEDs or relays. There are eight standard logic
outputs which produce 0V or +5V DC via an internal 440 Ohm resistor. Two common
(ground) connections are provided (connected together internally). A LED connected
between one output (Anode, A) and common (Cathode, K) will illuminate when the logic
output is activated, without requiring any external current limiting resistor. A high
sensitivity relay (such as a reed relay) may be driven by connecting four outputs in
parallel. This arrangement will develop 4V across a 500 Ohm coil, providing that all four
outputs are made logic 1 simultaneously.
Opto output
In addition to the eight standard logic outputs, there is an isolated output, which fails safe
(open circuit) if the 9088 becomes faulty. This is effectively the collector-emitter of a
transistor (which may be thought of as a switch) in series with a 220 Ohm protection
resistor. In conjunction with an external DC power source (max 80V), this may be used to
drive various loads such as relays.
47kOhm log
potentiometer
relay
switch
LED
relay
multiway
-
V
+V
