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RD122 RACK MOUNT DIMMER
Version 1.4
OWNER’S MANUAL
11/23/2021
www.lightronics.com
Lightronics Inc.
509 Central Drive, Virginia Beach, VA 23454
(757) 486-3588
UNIT DESCRIPTION AND FUNCTIONS
The RD122 is a 28,800 Watt, 12 channel, rack
mountable dimmer. Each of the channels has a
capacity of 2400 Watts. It is controlled via low
voltage signals which may be LMX-128 (3 wire
multiplex) or USITT DMX-512. The unit is fan
cooled. Channels may be independently assigned
from the unit. The unit is over temperature protected
and has a magnetic circuit breaker for each channel.
There are three options for channel output
connection panels. Options include: Duplex outlet
panel with 1 connection per channel, External
terminal strip (includes knockout cover) and
Socapex connector panel (wiring per customer
selection). The RD122 has several stand alone
functions which enable it to operate without a control
console. These functions include a storable scene
which may be activated by an external switch
closure, a programmable chaser and 7 factory set
chase patterns.
POWER REQUIREMENTS
Each RD122 requires both hots from a SINGLE
PHASE 120/240 VOLT AC or TWO PHASES OF A
THREE PHASE 120/208 VOLT AC service. The
neutral conductor is shared by two hots so it is
important the two hots used are of different phases.
EACH PHASE must be capable of providing 120
AMPS. Line frequency is typically 60HZ. A 50HZ
model is available for export. Refer to the dimmer
electrical rating markings to determine the operating
frequency. One or more RD122 dimmers may be
installed into a standard 19" equipment rack with
provisions for connection to an appropriate electrical
service in accordance with the National Electrical
Code.
INSTALLATION
PLACEMENT
The RD122 is designed to be mounted in a standard
19" equipment rack using the four mounting holes in
the face plate of the dimmer. If the dimming system
will be used for touring shows, it is recommended
you provide additional support for the rear of the
unit. The dimmer is fan cooled and requires no
space between units when multiple dimmers are
used. Air enters the dimmer through slots on the
side and exits through holes in the bottom of the
face plate. Make certain these ventilation holes are
not obstructed. Do not place the RD122 where it will
be exposed to moisture or excessive heat. The
RD122 is intended for INDOOR USE ONLY.
POWER CONNECTIONS
Consult your local electrical codes to determine the
proper wire type and wiring methods for your
installation.
Power enters the RD122 through a knockout sized
for 1” conduit at the rear of the unit. Remove the top
cover and install an appropriate cable clamp in the
knockout hole. Pass the power cables through the
hole. Behind the hole is a terminal block with three
lugs. The connections labeled "H1" and "H2" are the
line connections or "hots". The center connection
labeled "N" is the neutral. There is an additional lug
labeled "G" to the right of the terminal block. This is
for connecting the unit to earth ground. When
connections are completed, reinstall the cover and
tighten the cable clamp.
OUTPUT CHANNEL CONNECTIONS
The RD122 can be supplied with one of several rear
panel output options. Channel output connections
are according to the rear panel selected. Channel
connections generally proceed from left to right (if
you are facing th
e rear of the unit). Channel “1” will
be on the left end. On a unit supplied with edison
plug outlets, channels 1 - 6 are on the top row (from
left to right). Channels 7 - 12 are on the lower row
(from left to right). Connections for load Neutrals are
provided. There is also a ground lug terminal to be
used for your load circuit grounds.
CONTROL SIGNAL CONNECTIONS (Units with
DB9 connectors)
A control signal enters the RD122 through
connectors on the rear of the unit. If you are using
the 3 pin multiplex protocol ("LMX" or compatible),
plug the control cable into the 3 pin "XLR" connector.
If you are using the DMX-512 protocol, plug your 5
pin DMX control cable into the 5 pin to 9 pin adapter
supplied with the RD122 and plug the 9 pin
connector into the upper 9 pin connector on the rear
of the dimmer. In either case, the lower 9 pin
connector and the ribbon cable jumper that is
supplied can be used to connect from the lower
connector of the first dimmer into the upper
connector of the next dimmer and so on. See the
WARNING
MAKE CERTAIN POWER IS
REMOVED FROM THE FEED
CIRCUITS BEFORE YOU BEGIN
INSTALLATION.
