Lightronics AT SERIES User manual

Page 1 of 10
AT SERIES ARCHITECTURAL DIMMER
Revision 0.3 OWNERS MANUAL 03/16/2020
www.lightronics.com
Lightronics Inc. 509 Central Drive Virginia Beach, VA 23454 Tel [phone]
DESCRIPTION OF UNIT
The AT series dimmer is a unit specifically optimized for architectural applications. It can be supplied with up to
four 2400 Watt lighting circuits (channels) and be remotely controlled by a DMX lighting console. The AT series
dimmers are provided with a fast acting 20 Amp magnetic circuit breaker for each channel. A table at the end of
this manual gives a description of the different model numbers. The AT series dimmers can be supplied for 230
VAC operation.
The unit is intended for wall mounting. AT Series dimmers are for INDOOR USE ONLY.

Page 2 of 10
AT SERIES ARCHITECTURAL DIMMER
Revision 0.3 OWNERS MANUAL 03/16/2020
www.lightronics.com
Lightronics Inc. 509 Central Drive Virginia Beach, VA 23454 Tel [phone]
POWER REQUIREMENTS
The AT Series dimmer requires a 120 or 230VAC hot power feed line for each lighting circuit (channel), a common
neutral, and an earth ground. Each of these feeds must powered by a circuit providing a minimum of 20 Amps and
supplies only one of the AT Series dimmer lighting circuits. The power feed for channel 1 also powers the unit's
internal electronic circuitry. The internal circuitry is protected by a replaceable 1/2 Amp, 250 Volt, fast acting fuse.
The AT dimmer may be operated from either single phase or three phase power and may be switched between
these power types by the user.
INSTALLATION
LOCATION AND MOUNTING
The unit is to be wall mounted using the mounting holes provided in the chassis. Orient the unit such that the circuit
board is in the lower left area of the chassis. The unit may (but is not required to be) spaced out from the wall
approximately 1 inch. This may be desirable if the unit must be used in a location with a high ambient temperature.
Standard sized knockout holes are provided in the top, bottom and right side of the chassis for wiring. Be sure that
the vent holes in the chassis and cover are not obstructed since they are needed for proper cooling.
INPUT POWER CONNECTIONS
WARNING
Make sure that all power is removed from feed circuits before proceeding with wiring.
Connect power input leads to the lower terminal strip positions as indicated on the terminal strip labels. A hot feed
line is needed for each channel. Associated NEUTRALS are to be connected to the NEUTRAL bar provided. An
earth ground is also needed. A ground lug is provided. The terminal strip connection torque specification is 16 lb.-
in. max. The minimum wire size is AWG#12. Consult the applicable electrical codes for your location for exact wire
specifications. The power terminal connections are intended for copper wire only. This unit will work on either
single or three phase power. Any dimmer channel may get power from any phase.
LOAD CONNECTIONS
The AT Series dimmer is a triac based dimmer meant for forward phase loads. You can connect up to 2400 Watts
of lighting to each channel. Connect lighting loads to the upper terminal strip positions as indicated by the label in
the unit (see page 1). The neutral bar and ground lug may be used for lighting loads. The terminal strip connection
torque specification is 16 lb.-in. max.

Page 3 of 10
AT SERIES ARCHITECTURAL DIMMER
Revision 0.3 OWNERS MANUAL 03/16/2020
www.lightronics.com
Lightronics Inc. 509 Central Drive Virginia Beach, VA 23454 Tel [phone]
OPERATIONAL CONTROLS
The AT Series dimmer provides a user interface on the circuit board and connection points for switches to activate
scenes that can be preset into the AT series dimmer. This is also the connection point for the DMX control wires.
INITIAL SET UP
Set up of the AT Series dimmer is done using the 2 LED indicators and the 3 push buttons located at the bottom
left of the low voltage section of the circuit board inside of the unit. Use these controls to set the unit to operate
correctly for the type of input power being applied to the unit.
Set the Input Power Phase for each dimmer channel. This must be set correctly or dimmers will not operate
correctly.
Symbol
Function
Value
P2
Ch. 2 Input Phase
A, B, or C
P3
Ch. 3 Input Phase
A, B, or C
P4
Ch. 4 Input Phase
A, B, or C
For P2-P4, set to A, B, or C depending on which phase each channel gets its power from. For single phase power
set P2, P3, and P4 to "A".

Page 4 of 10
AT SERIES ARCHITECTURAL DIMMER
Revision 0.3 OWNERS MANUAL 03/16/2020
www.lightronics.com
Lightronics Inc. 509 Central Drive Virginia Beach, VA 23454 Tel [phone]
SET UP FOR A SINGLE PHASE POWER INSTALLATION
Press the NEXT button repeatedly until P2 appears on the LED indicator. This tells the unit which phase circuit 2 is
getting its power from, hence P2 (phase - Channel 2). Use the UP/DOWN buttons to set the right hand indicator to
"A". Do the same for P3 and P4 (phase - Channel 3) (phase - Channel 4).
SET UP FOR A THREE PHASE POWER INSTALLATION
Hold down the NEXT button until P2 appears on the LED indicator. Use the UP/DOWN buttons to set the right hand
indicator to "B" or "C". If the unit does not fade smoothly between preset levels or some of the channels seem to
operate in an OFF/ON only fashion then you should change this setting to the other three phase choice (B or C).
OPERATION
CIRCUIT BREAKERS
AT Series dimmers use a 20 Amp magnetic circuit breaker for each dimmer channel located on the right side of the
unit. To operate a channel, the associated circuit breaker must be closed. Channel numbers for the circuit breakers
are labeled on the unit. If a circuit breaker will not remain closed then there is an overload at the lamps for that
channel, which MUST be corrected before operation can continue.
INDICATORS
There is an LED indicator for each channel on the circuit board. They provide an indication of the current lighting
intensity for the associated channel.
DIMMER CURVE
Dimmer curves can be set independently for each of the available dimmers in an AT series unit. LL= LED (Lutron
LED or IN=Incandescent). To set the dimmer curve, press next until you see c1. Use the up/down buttons to select
LL or IN. Repeat on C2-C4 for each channel.
DMX OPERATION
The DMX channels are set by selecting the start address. The address is set on two separate menus dH for the
hundreds position (0-5, 0 being for any number lower than 100) and dL for the ten’s and one’s position (0-99). To
set the DMX address press the NEXT button until dH appears on the LED DISPLAY. Set the dH value to the first
digit of the 3 digit address using the UP/DOWN buttons. Then press the NEXT button again or until you see dL.
Set the dL value to the last two digits of the DMX address using the UP/DOWN buttons.
Loss of DMX: If there is a loss of DMX control signal during operation, the AT-402 will revert back to the last active
Preset until DMX operation returns.
EXAMPLE: Start address of DMX 509 dH=05 dL=09

Page 5 of 10
AT SERIES ARCHITECTURAL DIMMER
Revision 0.3 OWNERS MANUAL 03/16/2020
www.lightronics.com
Lightronics Inc. 509 Central Drive Virginia Beach, VA 23454 Tel [phone]
REMOTE SWITCH CONTROL
GENERAL REMOTE SWITCH OPERATION - A SMALL THEATER EXAMPLE
During theater operation, the lighting is controlled by external momentary switch closures either manually or by
automated equipment. The AT-402 dimmer is designed to activate preset lighting conditions in response to these
controls.
A simple scenario is described in the following table. The table is for an installation where a four channel unit is
used. AT-402 dimmer channels 1 and 2 are connected to the house lights and AT-402 dimmer channels 3 and 4
are connected to the stage lights.
REMOTE SWITCH CONNECTIONS EXAMPLE

Page 6 of 10
AT SERIES ARCHITECTURAL DIMMER
Revision 0.3 OWNERS MANUAL 03/16/2020
www.lightronics.com
Lightronics Inc. 509 Central Drive Virginia Beach, VA 23454 Tel [phone]
MANUAL ALL ON / RESUME OPERATION
The "All On / Resume" control may be activated by momentary external switch closure between one of the
"Common" terminals and the "All On / Resume" terminal of the circuit board Control Terminal Strip. . This function
overrides other switched channel controls and DMX input. It sets all channels to maximum intensity, and remains
in effect until the button is pushed again. At that time the unit will "Resume" normal operation (return to the intensity
settings provided by the other remote switch control signals).
ACTIVITY or PRESET
HOUSE LIGHTING
Channel 1
HOUSE LIGHTING
Channel 2
STAGE LIGHTING
Channel 3
STAGE LIGHTING
Channel 4
A Opening and Seating
90% (5 sec. Fade)
90% (5 sec. Fade)
90% (5 sec. Fade)
90%(5 sec. Fade)
B Introduction
50% (15 sec. Fade)
50% (15 sec. Fade)
0% (15 sec. Fade)
0% (15 sec. Fade)
C Main Performance
0% (5 sec. fade)
0%(5 sec. fade)
0%
0%
D Closing
60% (10 sec. Fade)
60% (10 sec. fade)
0%
0%

Page 7 of 10
AT SERIES ARCHITECTURAL DIMMER
Revision 0.3 OWNERS MANUAL 03/16/2020
www.lightronics.com
Lightronics Inc. 509 Central Drive Virginia Beach, VA 23454 Tel [phone]
PROGRAMMING THE UNIT:
The LED's will alternate between the SYMBOL (channel/preset level and preset fade) and its VALUE (intensity and
fade time). There are 2 digits and 3 buttons to control everything. Press the NEXT button to advance through each
SYMBOL. Press the UP and DOWN buttons to change the VALUE for the alternately displayed SYMBOL.
Note that the 100% intensity value on the LED display is indicated by "FL" (full).
You can STOP HERE, or continue and set the CHANNEL up/down fade times.

Page 8 of 10
AT SERIES ARCHITECTURAL DIMMER
Revision 0.3 OWNERS MANUAL 03/16/2020
www.lightronics.com
Lightronics Inc. 509 Central Drive Virginia Beach, VA 23454 Tel [phone]
TO SET THE INDIVIDUAL PRESET UP/DOWN FADE TIMES (or skip this section).These settings will over-ride
the fade up/down settings in the previous section.
SYMBOL FUNCTION VALUE
.A1 Channel 1, Preset A - up fade time 1-99 seconds
A1 Channel 1, Preset A - down fade time 1-99 seconds
.b1 Channel 1, Preset B - up fade time 1-99 seconds
b1 Channel 1, Preset B - down fade time 1-99 seconds
.C1 Channel 1, Preset C - up fade time 1-99 seconds
C1 Channel 1, Preset C - down fade time 1-99 seconds
.d1 Channel 1, Preset D - up fade time 1-99 seconds
d1 Channel 1, Preset D - down fade time 1-99 seconds
.A2 Channel 2, Preset A - up fade time 1-99 seconds
A2 Channel 2, Preset A - down fade time 1-99 seconds
.b2 Channel 2, Preset B - up fade time 1-99 seconds
b2 Channel 2, Preset B - down fade time 1-99 seconds
.C2 Channel 2, Preset C - up fade time 1-99 seconds
C2 Channel 2, Preset C - down fade time 1-99 seconds
.d2 Channel 2, Preset D - up fade time 1-99 seconds
d2 Channel 2, Preset D - down fade time 1-99 seconds
.A3 Channel 3, Preset A - up fade time 1-99 seconds
A3 Channel 3, Preset A - down fade time 1-99 seconds
.b3 Channel 3, Preset B - up fade time 1-99 seconds
b3 Channel 3, Preset B - down fade time 1-99 seconds
.C3 Channel 3, Preset C - up fade time 1-99 seconds
C3 Channel 3, Preset C - down fade time 1-99 seconds
.d3 Channel 3, Preset D - up fade time 1-99 seconds
d3 Channel 3, Preset D - down fade time 1-99 seconds
.A4 Channel 4, Preset A - up fade time 1-99 seconds
A4 Channel 4, Preset A - down fade time 1-99 seconds
.b4 Channel 4, Preset B - up fade time 1-99 seconds
b4 Channel 4, Preset B - down fade time 1-99 seconds
.C4 Channel 4, Preset C - up fade time 1-99 seconds
C4 Channel 4, Preset C - down fade time 1-99 seconds
.d4 Channel 4, Preset D - up fade time 1-99 seconds
d4 Channel 4, Preset D - down fade time 1-99 seconds
If individual times do not need to be set, then proceed to P2-P4 Channel Input Power Phase selection.
P2 Channel 2 Phase A, B or C
P3 Channel 3 Phase A, B or C
P4 Channel 4 Phase A, B or C
c1 Channel 1 Curve LL or IN (LED/INCANDESCENT)
c2 Channel 2 Curve LL or IN (LED/INCANDESCENT)
c3 Channel 3 Curve LL or IN (LED/INCANDESCENT)
c4 Channel 4 Curve LL or IN (LED/INCANDESCENT)

Page 9 of 10
AT SERIES ARCHITECTURAL DIMMER
Revision 0.3 OWNERS MANUAL 03/16/2020
www.lightronics.com
Lightronics Inc. 509 Central Drive Virginia Beach, VA 23454 Tel [phone]
MAINTENANCE
WARNING! RISK OF ELECTRICAL SHOCK
There are lethal voltages present in this product when power is applied to its feed circuits.
The cabinet should be opened only by a qualified electrician.
The only user servicable part in the AT Series dimmer is the Type ABC, ½ Amp, 250 Volt, fast acting fuse The fuse
may be replaced ONLY with an identical fuse.
WARNING!
Make sure that all power is removed from feed circuits before changing the fuse.
Service by other than the manufacturers authorized agents may void your warranty.
The best way to prolong the life of your unit is to keep it cool, clean, and dry. It is important that the cooling intake
and exit vent holes are clean and unobstructed.
MODEL NUMBERS AND CONFIGURATION
The table below shows the number of channels and circuit breaker information for each model number.
An additional suffix may also appear in the model number. This suffix is “/2” and indicated that the unit is for 230VAC
applications.
For one and two channel versions, only the components, indicators, and connection points for the applicable
channels will be present in the unit.
MODEL
NUMBER
DESCRIPTION
AT-402
4 Channels
AT-202
2 Channels
AT-102
1 Channel

This product is warranted for a period of TWO YEARS from the date of purchase against
defects in materials and workmanship.
This warranty is subject to the following restrictions and conditions:
A) If service is required, you may be asked to provide proof of purchase from an
authorized Lightronics dealer.
B) This warranty is valid only for the original purchaser of the unit.
C) This warranty does not apply to damage resulting from abuse, misuse, accidents,
shipping, and repairs or modifications by anyone other than an authorized
Lightronics service representative.
D) This warranty is void if the serial number is removed, altered or defaced.
E) This warranty does not cover loss or damage, direct or indirect arising from the use
or inability to use this product.
F) Lightronics reserves the right to make any changes, modifications, or updates as
deemed appropriate by Lightronics to products returned for service. Such changes
may be made without prior notification to the user and without incurring any
responsibility or liability for modifications or changes to equipment previously
supplied. Lightronics is not responsible for supplying new equipment in accordance
with any earlier specifications.
G) This warranty is the only warranty either expressed, implied, or statutory, upon
which the equipment is purchased. No representatives, dealers or any of their agents
are authorized to make any warranties, guarantees, or representations other than
expressly stated herein.
H) This warranty does not cover the cost of shipping products to or from Lightronics for
service.
I) Lightronics Inc. reserves the right to make changes as deemed necessary to this
warranty without prior notification.
Lightronics Inc. 509 Central Drive Virginia Beach, VA 23454
20100211
WARRANTY