Data; Connecting Fixtures - Martin MAC 550 PROFILE User Manual

D
ATA
Important! Never connect more than 1 data input and 1 data output.
The MAC 550 Profile has both 3-pin and 5-pin XLR sockets for DMX input and output. The pin-out on all sockets is
pin 1 to shield, pin 2 to cold (-), and pin 3 to hot (+). There is no connection to pins 4 and 5.
The sockets are wired in parallel: both inputs connect to both outputs. For reliable data transmission and to avoid
damage to the fixture, however, use one input and one output!
Tips for reliable data transmission
• Use shielded twisted-pair cable designed for RS-485 devices: standard microphone cable cannot transmit
control data reliably over long runs. 24 AWG cable is suitable for runs up to 300 meters (1000 ft). Heavier
gauge cable and/or an amplifier is recommended for longer runs.
• Never use both outputs to split the link. To split the serial link into branches use a splitter such as the Martin
4-Channel Opto-Isolated RS-485 Splitter/Amplifier.
• Do not overload the link. Up to 32 devices may be connected on a serial link.
• Terminate the link by installing a termination plug in the output socket of the last fixture. The termination
plug, which is a male XLR plug with a 120 ohm, 0.25 watt resistor soldered between pins 2 and 3, "soaks
up" the control signal so it does not reflect and cause interference. If a splitter is used, terminate each
branch of the link.
• Martin fixtures introduced before 1997 have reversed polarity data sockets (pin 2 hot and pin 3 cold). The
socket polarity is labelled. Use a phase-reversing cable between the MAC 550 Profile and any Martin device
with reversed polarity.
To connect the data link
1 Connect the DMX data output from the controller to the MAC 550 Profile's 3-pin or 5-pin input (male) socket.
2 Using the sockets that match your data cable, connect the output of the fixture closest to the controller to the
input of the next fixture.
3 Insert a male 120 XLR termination plug in the 3-pin or 5-pin output of the last fixture on the link.

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