POWERdrive 50W DESIGN GUIDE
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July 30, 2020
Page 9/19
DMX Wire type
The DMX protocol operates over an RS-485 physical layer at 250kbaud. To comply with the standard, cabling with specific
operating characteristics must be used to support this fast, digital signal.
DMX-compliant cables should be used for both the input and output connections to a luminaire. If multiple DMX LED
drivers are used within the same luminaire, DMX-compliant cables should be used between the LED drivers. Best practice
is to provide as much separation as possible between power wires (mains or LED outputs) and DMX signal wires within the
luminaire.
Check the DMX512-A standard for the technical requirements on DMX cabling. In general, a DMX cable contains a twisted
pair with a low capacitance and a nominal characteristic impedance of 120
Ω
; the cable can be shielded or unshielded. An
example of a DMX-compliant cable is Belden 9841. A category 5 or above network cable is also compliant.
Figure 5: Proper wiring of a DMX fixture is critical to trouble-free operation. To facilitate daisy-chaining of multiple
luminaires in a DMX network, each luminaire should provide separate DMX IN and DMX OUT connections. This can be
accomplished as shown here. The
“T
-
tap”
connection to the DMX IN terminals of a POWERdrive LED driver within the
luminaire should be made as short as possible, preferably less than 2 -3 inches.
