Extron electronics MediaLink MLC Plus 50 - Page 31

MLC Plus 50/100/200 Series • Hardware Features and Installation 23
• Digital input with pull-up enabled
• The +5.0 VDC pull-up resistor is enabled (switch 2 is closed when configured
for pull-up).
• An external short to ground creates a logic low.
• An open circuit acts a logic high
• Example application, digital input with pull-up: connecting a two-position switch
+5.0 V
1k ohms
SW 2
Two-position
Switch
Digital
Input
GND
Voltage
Protection
CTL
Figure 22. Digital I/O Digital Input Application:
Two‑position Switch With Pull‑up
Two-position switch is open: digital input is +5 VDC, logic high.
Two-position switch is closed: digital input is 0 VDC, logic low.
F
Relay ports — Relay ports provide control for power, screen or projector lifts, window
coverings, and similar items,
when trigger events occur.
These relay contacts may be used
to control any equipment as long
as the contact specifications of
a total of 24volts at 1ampere
are not exceeded for each port.
These relays are normally open by
default.
When activated, the open contacts
close. They can be set up to
operate in one of two ways:
• Latching (brief or indefinite
period contact) (press to
close, press to open), or
• Pulsed (timed cycle) (press to
close, timeout to open, with
automatic repeat).
Use Global Configurator to change the length of the timeout period.
NOTE: The pulse function is absolute: it always sets the relay state to closed, times
out (briefly), then opens the contact. It overrides the previously selected setting
(on state, off state, or toggle).
12
C
G
IN
DIN
RELAYS
Rear
Panel
Normally
Open
Common
To Room
Control
Equipment
Closed
Normally
Open
All relays are
normally open.
Relays
• Connect devices for relay control.
• Do not exceed a total of 24V, 1A
for each port.
Figure 23. Cabling Relay Ports