LMI RD Dimmer Rack Overview
The RD-2033 module controls the power regulation for the rack
The RD-2033 module has four LEDs on the front. Three of them are for PHASE A, B, and C to let you know that voltage is present at these phases or not. The other LED represents the DC voltage that feeds the dimming cubes.
The RD-2031B Module is your signal converter card. This card converts your incoming console control signal (either DMX , LMI, and many other protocols) into a control protocol called Micro2 which is used by the RD-2034 modules to turn the lights on and off. This card is not used in all systems, only systems with a DMX or LMI control console. If you were to remove this module you would see a chip with a sticker containing your system number on it. All of these cards contain site specific custom programming.
The RD-2034A Modules are your dimmer firing cards. These convert the Micro2 signal from the 2031B card into Pulse width signal to fire the dimmers and dim your system. These modules are addressable based on your system configuration and each card controls a phase of dimmers in the rack. As you can tell by looking at the rack there are 6 2.4k modules across each row. Phasing is based on each module slot. For the dimmers this phasing is A,B,C,A,B,C in each row. The addresses on the front card determine the signal start number and the rest of the electronics are smart enough to understand which dimmers get fired based on what the console is turning on. In most systems the cards are addressed as 1,5 and 9.
So looking at the top row:
- The Left hand 2034 card controls 1,2,7,8
- The Center 2034 card controls 3,4,9,10
- The Right hand 2034 controls 5,6,11,12
This continues through the rack in series. Based on this if you are having a problem with one of these cards the associated dimmers to the card will be affected.
The RD-2035 cards are analog control cards which control Houselights/Architectural lights. These cards combined with a series of relays wired to the back of the rack behind the cards and interpret button hits from your house and panic control stations and their faders. The button hits on the stations trigger the relays inside the rack and the faders send analog control signal to the card which converts the analog signal into pulse width signal to turn the dimmers on and off. In most systems the houselights are not controlled by the console and the console cannot control the houselights. In all cases the stations are hardwired to the relays and it was custom installed. If you need to troubleshoot the architectural side of the system job prints are essential.
Everything everything you always wanted to know about RD dimming, but were afraid to ask. (From Mike Meskill and David North in 2001)
This document is provided as a guideline for RD dimming system design and architecture. As with many early LMI products, customization did occur occasionally. For any systems in the field that do not subscribe to the following information, with the help of this document, you should be able to troubleshoot from the basic facts.
Note: RD touring racks were manufactured by LMI and several dealers at the time. They tend to be different in construction, control, and bussing.
Control Signal Definitions:
Micro II: LMI control signal primarily used in the RD card cage backplane to pass dimmer values from the receiver card to the ramp cards. There are a few RD racks that use this as control from a console to the ramp cards in the rack directly.
FastPatch: LMI control signal usually found on the output of a FastPatch unit (the predecessor to the Response Network Controller). Truss dimmers (TD dimmers) accept this signal.
Control Cards:
RD control cards can be broken down into basic form and functions.
RD2031: Digital signal receiver card. Translates Micro II, AMX, or FastPatch to Micro II. Can contain dimmer tabling.
RD2031A: Digital signal receiver card. Translates Micro II, AMX, or FastPatch to Micro II. Can contain dimmer tabling.
RD2031B: Digital signal receiver card. Translates Micro II, AMX, DMX, Colortran, ECMux, or K96 to Micro II. Can contain dimmer tabling.
RD2033: RD card cage power supply card.
RD2034A: Micro card. Converts Micro II into 0-5vdc pulse-width output dimmer signals. May have slide switches for backup assignments.
RD2034C: Micro card. Converts Micro II into 0-5vdc pulse-width output dimmer signals. Also has direct 0-10vdc analog input control of dimmers. May have slide switches for backup assignments.
RD2035: Ramp card. Converts 0-10vdc input into 0-5vdc pulse-width output dimmer signals.
Please note the different control protocols that each RD2031 card can work with. The RD2031B can
Dimmer modules:
Over the production years, and continuing today, there were a number of dimmer modules and their variants available for RD racks.
RD0000: Blank module
RD1200: 4 x 1.2kW module. Used either 4-Q116 cubes or 2-Q119 cubes. Used only two chokes placed on input instead of output.
RD2400: 2 x 2.4kW module. Used 2-Q116 cubes and two chokes.
RD6000: 1 x 6kW module. Used 1-Q115 cube and two chokes.
RD2400C: 2 x 2.4kW constant module. These were not on the official list but are known to exist.
RD2400ND: 2 x 2.4kW non-dim module. ???
Early dimmer module production included items such as split power pins, hand-wound chokes and single density power cubes. Later on, Chinese lantern power pins and dual density power cubes were used, although not necessarily simultaneously.
Very late racks used sil-pads for heat conduction between the cube and the heatsink. This does not seem to cause a problem since the extrusion and the cube both have very flat surfaces.
Split power pins cause most of the problems with modules and racks, especially after numerous insertions. The pins lose their spread and arcing begins. This should be checked yearly.
Rack layout and phasing:
RD racks consist of a stack of chassis in 19” cabinets. Working from the bottom up will be:
RD2432 High Slope Panel: This is a one space high chassis that generates the zero crossing ramp signals to the RD2034 cards and power to the fan chassis. Three fuses protect each of the three phase inputs to the high slope card and to the three neon lamps.
RD2030 Electronics Chassis: This is a three space high chassis that contains all of the slide in control cards.
RD2420 Fan Chassis: This is a four space high chassis that contains two B105 flat fans and a fiberglass filter assembly.
RD2415 Dimmer Chassis: This is a four space high chassis that contains slide in dimmer modules.
There have been several different phasing configurations in RD racks. We will discuss the most common.
In the six slots available for dimmer modules in the RD2415 chassis, from left to right, the phasing is ABCABC. As far as Micro cards are concerned, control will be 123123 or 456456 depending on which part of the rack you are in. The top part of the rack will be controlled by the first three RD2034 cards and the bottom half of the rack by the last three Micro cards.
Each Micro card will control up to 18, 20 or 24 dimmers. This is determined by the software that is in the EPROM. The EPROM label will state DIM18, DIM20, or DIM24. Therefore, to control 96 dimmers, you will need 6 Micro cards using DIM18 software or greater. It should be noted that you can have an Micro card with software greater than the number of dimmers needed to control, but DIM24 software may occasionally flicker based on update rates and processor speed limitations.
The split between the top part of the rack and the bottom part of the rack is determined by the RD2034 software and the job code in the RD2031 card. If you have job prints for the rack you are maintaining, there is a page that will show you the Micro card to dimmer assignments.
