# Build a desk profile from the fixture

- **MCP resource:** rdmbench://help/desk-profile
- **Version:** 0.2.0
- **Runs on:** macOS 15 Sequoia or later, Apple silicon or Intel
- **Needs:** An Enttec DMX USB Pro with its DMX/RDM firmware (major version 2)
- **Price:** Free

A desk patches a fixture with a profile: what each channel does in each
of its modes. Desks call it different things (see
[Three kinds of profile](/help/fixture-files/#three-kinds-of-profile)).
When the manual's channel table doesn't match what the fixture does,
the bench can tell you what the fixture says about itself, which is the
part to trust. It doesn't write the profile: there
is no file for Eos, grandMA or any other desk, and no GDTF file. You
copy what the bench reads into the desk's own fixture editor. How much
it can read depends on what the fixture reports.

## When the manual seems wrong

Check the mode before rewriting a profile. Usually the manual is right
about some mode, just not the one the fixture is in: a model sold in a
short and a long version, a firmware update that changed the list of
modes, or a desk patched in one mode while the fixture runs another.
The report's **DMX configuration** says which personality the fixture
is in and how many channels it takes. If that is not the table you are
reading, that is the fault (see
[Wrong colors: check the patch](/help/address-mode/)). Where the
bench has the model's GDTF file, it also says what a desk calls that
mode (see [Find a fixture's desk mode](/help/desk-mode/)), and
a desk profile may already exist.

## A fixture that reports its channels

Some fixtures report a slot table: a name, a kind and a starting level
for every channel of the mode they are in. The report's **Channels**
list shows it. That is the fixture's own map of the mode, and it wins
over the manual.

- **Every mode and its channel count:** choose **Fixture → Contribute
  Fixture Profile…**. The sheet reads every personality the fixture
  offers. **Cancel** closes it having sent nothing.
- **The channels of another mode:** a fixture reports only the mode it
  is in. Switch it to another mode at its menu, or with
  `rdmbench-cli set-personality 2` (the second mode in its list), and
  take the report again.

A slot table names a channel, but it doesn't say where each color or
gobo sits along it. For that, put the channel up and look (below).

## A fixture that reports no channels

Many fixtures answer RDM without a slot table. The report still gives
the mode and its channel count, so the desk's profile can at least be
the right width. Where the PID library has a profile for the model, its
channel names come from the manual and show *profile* beside them in
[Send DMX](/help/send-dmx/#the-channel-list). Otherwise every
channel is just "Channel 1", "Channel 2" and so on.

To map them, raise one channel at a time in **Fixture → Send DMX…**
and write down what it does. Or run a
[channel walk](/help/channel-walk/): it puts each channel up in
turn, and your note for each one is kept with the unit. Work in the
mode the desk will use, and raise a dimmer first. On many fixtures,
nothing shows until the master dimmer is up.

## A fixture with no RDM

There is nothing to read. If the bench finds no fixture and the
manual's menu has no RDM setting, the fixture doesn't support it (see
[When no fixture is found](/help/no-fixtures/)). Map it from the
desk's own faders, or from the bench with `rdmbench-cli dmx 1=255`,
which puts a level on a DMX channel with no RDM at all.

## Writing it into the desk

- Make the desk profile's channel count match the fixture's exactly.
  One too short leaves the last channel unpatched. One too long
  overlaps whatever is addressed next.
- Note the fixture's firmware version beside the profile. A firmware
  update can change the modes and their channels, and the report says
  which firmware this unit runs.

## From the command line

`rdmbench-cli slots` prints what each channel of the current mode does,
and where that came from. `rdmbench-cli export-profile` lists every
personality with its channel count. `rdmbench-cli set-personality 2`
switches to another mode. `rdmbench-cli walk` and `rdmbench-cli dmx`
put channels up.