Configuring a New Nicos Instrument - ISISComputingGroup/ibex_developers_manual GitHub Wiki

Wiki > The Backend System > Nicos > Configuring a new Nicos instrument

Nicos instruments configurations are stored under nicos-facility/inst-name/. These configurations are designed to be very modular.

An instrument requiring the Nicos daemon must have, as a minimum, a setups/ directory containing two setup files:

• daemon.py, which contains configuration parameters to run the daemon. This file is usually located in a special/ subdirectory, which would normally contain all the setup files for the Nicos services to run (e.g. cache.py when the Nicos cache is needed). Some documentation about the daemon setup file is available [here] (http://cdn.frm2.tum.de/fileadmin/stuff/services/ITServices/nicos-master/dirhtml/services/daemon/).
• startup.py, which doesn't have to contain much at all, but Nicos won't run without it. The startup files of various FRM II instruments contain the following comment:

# The startup setup is loaded first thing on NICOS session startup.  It should
# usually stay empty.  In particular, it should not include any other setups
# without good reason, so that on startup the previous master setups are loaded
# automatically.

A Nicos instrument can then have any number of additional setup files in the setups directory, each specifying a set of devices and commands that the daemon is configured to recognise (see for example Nicos demo). A setup file called system.py if present, is always loaded. Here we can define a modules section, listing the file names of the modules that should be included. Command files can be located in:

• nicos-core/nicos/commands in the case of generic Nicos commands
• the instrument's own directory in the case of instrument-specific commands

More documentation on the setup files is available [here] (http://cdn.frm2.tum.de/fileadmin/stuff/services/ITServices/nicos-master/dirhtml/setups/#setups).

It looks like it's possible for an instrument to include setup files from another instrument too, as long as it is listed in the setup_subdirs section of a file called nicos.conf in the root instrument directory (e.g. see antares/, which includes frm2/). NOTE: this hasn't been tested, but if it's the case it would allow us to have a basic Ibex instrument containing core commands and settings common to all Ibex instruments, without committing new files to the core nicos/commands directory.

To run the Nicos GUI, the instrument must have a guiconfig.py file in the root instrument directory (if copying from another Nicos instrument, make sure any hard-coded path containing the instrument name is adjusted correctly).

If no instrument is specified, Nicos will run demo by default.

There are at least two ways of specifying which instrument to run:

• have an environment variable called INSTRUMENT containing the instrument's facility and name in the format _facility_._name_: Nicos will then look for an instrument with that name under facility/
• have a nicos.conf file in the root nicos-core/ directory, pointing at the instrument and facility we wish to run. For example, to run the instrument ibex in nicos_isis, the file would contain:

[nicos]
instrument = ibex
setup_package = nicos_isis

Now, as we need the correct EPICS and CA environment variables to be set for running genie_python commands (and ultimately Nicos to run with all the other Ibex instrument processes), we need to launch Nicos processes through an EPICS terminal. This terminal already sets an INSTRUMENT environment variable, and so the start_script_server.bat will override this to be the ISIS default.

For testing purposes though, it's more convenient to have a nicos.conf file specifying the instrument to launch, even when running from an EPICS terminal.

Instructions on how to run Nicos can be found here.