Acclaim Lighting DDC-1-AC, Руководство пользователя

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CONFIGURATION
DALI operates at just 1200 bits per second; this slow speed means that it will remain robust
and reliable when transmitted across standard cabling (with no termination); its control
cables can be run alongside high voltage power feeds and its devices can be arranged in
mixed topologies. Compare this against the much faster speed of 250,000 bits per second
for DMX; making DALI roughly 200 times slower. DMX is a streaming protocol, meaning
that the values for each of its 512 channels are continually re-transmitted, roughly 44 times
every second. By contrast, DALI is a vector protocol, which means that a command is only
transmitted when a change occurs.
When converting from DMX to DALI, the wide mismatch between the speeds of the two
protocols means that care should be taken to minimise complex dimming changes across
multiple DALI fixtures. Attempts to reproduce subtle colour changes or real-time fades
across individual DALI fixtures will result in very ‘steppy’ and unattractive results. This is
caused by interim values being discarded because the DALI bus cannot keep pace.
DMX TO DALI MODES
In DMX to DALI mode, the DDC-1-AC unit supports two DALI control modes:
• Channel
- [sw10: ON, sw11: ON] In this mode, the 64 DALI
channels will be assigned to 64 separate DMX channels
(beginning at the chosen start address) to provide maximum
control flexibility. However, this mode will impose the largest data
overhead on the DALI bus and could produce unattractive results.
• Broadcast
- [sw10: ON, sw11: OFF] In this mode, all of the 64
DALI channels will be assigned to the single DMX channel that
is chosen using the start address switches. This will provide the
best response times as only a single set of instructions need to be
issued across the whole DALI bus. However, all of the fixtures will
respond in the same way.
See page 8 for more details about switch settings.
NOTES
•
DALI addresses are numbered from 0 to 63, whereas DMX channels are numbered from 1
to 512.
•
If the DMX signal is lost, all DALI fixtures will return to their off condition.
•
RDM signals present on the DMX bus are not passed across the conversion process.
•
Query commands on the DALI bus are not passed across the conversion process.
DMX DALI
0
1
.
.
.
63
1
DMX
1
2
64
DALI
0
1
63