Lightronics RD121 - Manual (Page 4)

Page 4 of 13
RD - 121 RACK MOUNT DIMMER
Version 1.2
OWNERS MANUAL
02/28/2005
www.lightronics.com
Lightronics Inc. 509 Central Drive, Virginia Beach, VA 23454 (757) 486-3588
OUTPUT CHANNEL CONNECTIONS
The RD-121 can be supplied with one of several rear panel output options. Channel output connections are
according to the the rear panel selected. Channel connections generally proceed from left to right (if you are
facing the rear of the unit). Channel “A” will be on the left end. Connections for load Neutrals are provided. There
is also a ground lug terminal to be used for your load circuits grounds.
CONTROL SIGNAL CONNECTIONS
A control signal enters the RD-121 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 RD-121 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 included drawings at the back of this
manual for clarification. The RD-121 is shipped with the power supply set to provide +15 volts DC console power
when using the 3 pin multiplex protocol. Note that the DMX-512 protocol does NOT provide a means for console
power via the control cable. Systems using the DMX protocol must have console power supplied by other means.
SETUP
The RD-121 has a front panel LCD display and operator controls. The display indicates dimmer status
information and is used with the operator control buttons to set up and monitor dimmer operation. A menu system
is used to access the various features of the RD-121. During normal dimmer operation the display shows the
current intensity setting for each channel and indicates what type of dimmer control is in affect. This is called the
STATUS DISPLAY and is shown in the diagram below.
STATUS DISPLAY AND OPERATOR CONTROLS