LSC Lighting MDR Splitter - Manual (Page 8)

MDR DMX512/RDM Data Splitter Operator Manual
Page 6 LSC Lighting Systems (Aust) Pty Ltd.
RDM Explained
RDM is an acronym for Remote Device Management which is a relatively new protocol that
overlays on the existing DMX512-A cable network, using the same 3-pins of the XLR
connector. The protocol has been released under the standard ANSI-E1.20-2006. Equipment
connected to the DMX512-A network wishing to use the advantages of RDM, must be RDM
compatible.
Unlike DMX512-A, RDM is bi-directional – meaning messages sent out can be responded to
and reported back to the originator. This can allow RDM controllers to interrogate, control
and report on any RDM enabled devices on the network, by:
 changing DMX start addresses
 reporting faults
 changing fixture mode settings
 requesting a list of fade curves available from a dimmer rack
 report on lamp hours usage per fixture
 temperature reporting of dimmers and other connected devices
and so on…..
RDM will allow a lighting console to discover all the devices connected to its outputs and
even to know how many DMX slots each item requires. This information could then be used
to auto-patch the entire rig. The user settings of all the devices could be saved as part of
the show file, so that when the show is re-loaded into the console, the system could ensure
that all devices are still connected and working, then check that the Pan invert settings and
custom dimmer curves on certain devices have not changed. In the case of a faulty moving
light, a new light could be connected and the user settings (eg. DMX address, mode, Tilt
invert) automatically uploaded to the new unit.
RDM is backwards compatible with existing DMX512 equipment, allowing non RDM devices
to be connected to the same cable as RDM devices. The non-RDM units, if fully conforming
to the DMX512-A standard, will simply ignore all the RDM data. The only exception to the
rule is DMX512-A data splitters. Non RDM units will simple block (stop) all RDM data from
any devices connected downstream of the DMX512-A splitter. Therefore any lighting system
using RDM must use RDM enabled DMX512-A data splitters.
Once the uptake of RDM by other manufacturers reaches levels where the majority of
equipment is RDM compatible, the advantages of RDM will become obvious and many users
will wonder how we survived without it.