Leprecon LD-360 - Manual (Page 8)

MIDI System Interface
Even disregarding the MIDI System Interface, the LM-850 functions beautifully as a multi-scene mem-
ory console, with lots of memory for storing scenes, chases and songs. The MIDI capabilities add much
more versatility, however. In conjunction with a computer (with the necessary MIDI interface and
software), or with a sequencer, the user can store and recall scenes, chases, songs, and even console
setups, and record and edit a performance in either real time, or by typing in a group of specific com-
mands. Such a setup allows a complete lighting show to be recorded and then played back flawlessly each
time, synced perfectly to the music. With a SMPTE-to-MIDI interface or a MIDI-tape sync unit, the LM-
850 can be even synchronized to tape recorded music, video, or any type of recorded program. It is
through the MIDI System Interface-the In, Out, and Thru jacks on the LM-850's rear panel-that the
console can communicate with any other MIDI device.
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sizer, effects unit, or other device, a new program can be accessed. On a synthesizer, this would call up a
different sound from memory, making it active on the keyboard. With an effects device, a program
change might switch from a chorus program to a reverb setting. On the LM-850, program changes are
used to select the Next Scene (anyone of the 100 scenes in memory) while in Scene mode, to step
through song steps while in Song mode, or to step through chase steps while in Chase mode. There are
128 program numbers (0 through 127) recognized by MIDI.
MIDI is a serial communications protocol, operating at 31.25 kilobaud, and connections are made
through 5-pin DIN connectors (only three of the pins are actually used). There are three types of MIDI
ports: MIDI In, MIDI Out, and MIDI Thru. Similar to an audio setup, the MIDI Out of one device feeds
the MIDI In of another. If you are sending data from a keyboard to the LM-850, then, you should plug a
MIDI cable from the MIDI Out jack of the keyboard to the MIDI In jack of the LM-850. The MIDI Thru
port allows for daisy-chaining devices together; it sends out an exact replica of the data that comes into
the In port. Note that this is different from the MIDI Out, and often leads to confusion. The MIDI Out of
a device sends only the data that that device generates. The MIDI Thru sends out only the data that the
device receives from the MIDI In.
.
The LM-850 is set up to run two completely separate MIDI “networks" -one in the normal fashion (the
System Interface), which connects the LM-850 to sequence, computers, etc, and one specifically for
operating special MIDI-controlled dimmers. The two networks are completely independent-MIDI data
from one cannot "bleed over" to the other.
MIDI Dimmer Interface
The MIDI Dimmer Interface, with three MIDI Outs, is used for the sending of channel level data from
the console to MIDI-controlled dimmers, such as the Leprecon LD-360M. This is provided in addition to
the DMX-512 dimmer output, which works at a higher speed, but requires an expensive decoder for use
with analog dimmers. The MIDI dimmer outputs are specially equipped so that cable lengths are not
limited to the usual fifty feet (as outlined in the MIDI Specification)-runs of several hundred feet will
work fine with quality low-capacitance cables.
The MIDI dimmer outputs are switchable to send either MIDI continuous controller data or MIDI note-
on/off data. Leprecon MIDI-controlled dimmers respond to either data type. Continuous controller output
should normally be used, because it is more efficient, and doesn't require as much data transmission.
However, the note-on/off output is useful for connecting the LM-850 dimmer output to a synthesizer or
other MIDI device that responds only to note data. In note mode, because more data must be sent, a
slight lag in dimmer response time may be apparent when controlling a large number of channels
simultaneously.