Leprecon LD-360 - Manual (Page 5)

Using MIDI Thru connections to daisy chain LD-360M dimmers
The MIDI specification carefully and strictly defines the MIDI line driver and receiver hardware to be
used, and the impedance’s to be maintained. In order to be real MIDI ports, MIDI inputs must load the
line fully, and MIDI THRU ports must therefore be actively buffered in any equipment which has a
THRU port.
This is the reason that any MIDI device, including our LD-36OM MIDI dimmer, will stop passing the
MIDI signal from it’s IN to it's THRU port when it is not powered. This means that if a string of dim-
mers are daisy-chained in series, turning off any dimmer will block the MIDI control signal from
passing to the subsequent dimmers in the chain.
If this is a problem, there are several solutions. First, you can use the three MIDI OUTS on the LM-850
controller to feed three MIDI dimmers directly, without daisy chaining. If it is desired to run one MIDI
cable from the console to the general location of the dimmers and then split the signal to the dimmers,
you can buy a "MIDI THRU Box" from several manufacturers which buffers the MIDI signal and
outputs it from a number of THRU ports which can then be connected directly to the MIDI dimmers.
MIDI buffer boxes, patchers (smart buffer boxes), and many other neat MIDI signal splitting, merging,
filtering and patching gizmos are available from lots of companies including J.L. Cooper, KMX (2x8
merge-select box from $175. list), Digital Music etc. Check a copy of Electronic Musician for manu-
facturer’s names and addresses, reviews, and mail order distributors or stop by your local music store
specializing in MIDI equipment.
MIDI Control Cables
MIDI control cables are two conductor plus shield with male 5 pin 180' DIN connectors on each end.
Pin 1 and shell
= shield, pin 5 = data (sink), pin 4 = +5v drive source. The MIDI standard specifies a
maximum of fifty foot cables, but with the use of low capacitance cable such as we supply, runs of
hundreds of feet are reliable. The LM-850 console has high current output drivers which allow even
longer cable lengths. All MIDI inputs are opto-isolated, so ground loops and associated problems are
minimized.
DIMMER FEATURES
Load Capacity
The LM-850 MIDI and MIDI-HP dimmers are identical as far as control connection is concerned. They
differ in load capacity only. Either pack can control a maximum of 15 amps (1800 watts) of lamp load
on any one channel...but the maximum total pack load is limited to 15 amps or 2400 watts per power
cord by the noise filter current capacity and the heat dissipation capability of the chassis.
Because the most generally available electrical outlet in the U.S. is the parallel blade U-ground, we have
supplied the packs with this type of power plug. The maximum current rating of these connectors as
specified by the National Electrical Code is 15 amps..so the total load per cord cannot exceed this
capacity without a connector change.
.
*NOTE- The 360-HP versions are designed for economy and are not designed for 100% duty cycle full
power operation! Please do not operate at 100% load all full up for over 5 minutes. Allow 5 minutes
50% up or less cool down period.
Power Increase
If the connector on the end of the power cord is replaced with one rated for 20 amps, and a 20 amp
circuit is supplied, the total available pack capacity will be the full 20 amps. The HP version would
require both power plugs be changed.
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