Wiring the Digital Input Port (RS Models Only)
The Digital Input port on the MLC rear panel lets you connect a switch or sensor to control
other devices in the room that are connected to the MLC serial, IR, and relay ports. This
port measures two states — high and low — of the connection between the switch or
sensor and the connected device. The port accepts 0 to 24 VDC input. The threshold
voltages are as follows: a voltage below 1.0 VDC is measured as logic
low
, and a voltage
above 1.5 VDC is measured as logic
high
.
There is also an internal, +5 VDC, selectable, pull-up resistor for this circuit. If a connected
device does not have its own power source and will be powered through the controller,
configure this port (via the MLC configuration software) with
Input with Pullup
as the digital
input mode. If the connected device provides its own power, select
Input
for the digital
input mode (see the
MLC 55, 62 and 64 Series Configuration Program Help File
to select
the digital input mode).
In addition, you can program actions on this port, so that each time a high or low state is
detected, one or more functions are performed. An example of this is front panel lockout,
or executive mode (see the configuration software help file to configure the Digital Input
port).
To wire the Digital Input connector:
1.
Connect the ground port of the input device to pin 2 of a provided 2-pole captive
screw connector.
2.
Connect the signal port of the input device to pin 1 of the captive screw connector.
3.
Plug the wired connector into the MLC rear panel Digital Input connector.
Example:
The diagram below shows a two-position switch connected to the Digital Input
port of an MLC 62 RS D.
Ground ( )
Digital Input 1
Rx
Tx
GROUND
Tx/IR
COMMON
1
1
2
HOST/
CONFIG
RS-232
IR/
S
DIGITA
L
INPU
T
Tx
PW
R
12
V
0.2 A MA
X
RELAYS
N/
O
GROUND
GROUND
GROUND
GROUND
+12 VDC
MLC 62 RS D Rear Panel
Two-position Switch
1
2
Pin:
Figure 24.
Connecting a Two-position Switch to the Digital Input Port
MLC 60 Series MediaLink Controllers • Features, Installation, and Operation
27