Introduction

lvmnps allows for basic, homogeneous control of a variety of network power supplies (NPS). Currently the supported NPS are

• Digital Loggers Inc devices, in particular the Pro Switch

• NetIO devices.

The code allows to retrieve the status of the various outlets, set outlet status (on, off, cycle), and execute user functions (only for DLI devices).

Installation

lvmscp can be installed using pip as

pip install sdss-lvmnps

To install lvmnps for development, first clone the repository

git clone https://github.com/sdss/lvmnps

and then install using poetry

poetry install

Using the library

To connect to an NPS, first import the switch client class (available implementations are DLIClient and NetIOClient) and instantiate them with the appropriate parameters. Then call NPSClient.setup to initialise the connection and refresh the list of outlets.

from lvmnps import DLIClient

client = DLIClient(host='127.0.0.1', port=8088, user='admin', password='admin')
await client.setup()

We can then retrieve the list of outlets and their status

   >>> client.outlets
   {'argon': DLIOutletModel(id=1, name='Argon', normalised_name='argon', state=False, index=0, physical_state=False, transient_state=False, critical=False, locked=False, cycle_delay=None),
'neon': DLIOutletModel(id=2, name='Neon', normalised_name='neon', state=False, index=1, physical_state=False, transient_state=False, critical=False, locked=False, cycle_delay=None),
'ldls': DLIOutletModel(id=3, name='LDLS', normalised_name='ldls', state=False, index=2, physical_state=False, transient_state=False, critical=False, locked=False, cycle_delay=None),
'quartz': DLIOutletModel(id=4, name='Quartz', normalised_name='quartz', state=False, index=3, physical_state=False, transient_state=False, critical=False, locked=False, cycle_delay=None),
'hgne': DLIOutletModel(id=5, name='HgNe', normalised_name='hgne', state=False, index=4, physical_state=False, transient_state=False, critical=False, locked=False, cycle_delay=None),
'xenon': DLIOutletModel(id=6, name='Xenon', normalised_name='xenon', state=False, index=5, physical_state=False, transient_state=False, critical=False, locked=False, cycle_delay=None),
'outlet_7': DLIOutletModel(id=7, name='Outlet 7', normalised_name='outlet_7', state=False, index=6, physical_state=False, transient_state=False, critical=False, locked=False, cycle_delay=None),
'outlet8': DLIOutletModel(id=8, name='Outlet8', normalised_name='outlet8', state=False, index=7, physical_state=False, transient_state=False, critical=False, locked=False, cycle_delay=None)}

All outlets share some common attributes, including id (a numerical identifier), name, normalised_name (a normalised version of the name, useful for programmatic access), and state (the current state of the outlet). Certain types of outlets may include additional parameters.

To retrieve an outlet by name or id

>>> client.get(5)
DLIOutletModel(id=5, name='HgNe', normalised_name='hgne', state=False, index=4, physical_state=False, transient_state=False, critical=False, locked=False, cycle_delay=None)

To refresh the internal state of the outlets you can issue

await client.refresh()

And to switch an outlet on or off

await client.set_state(5, on=True)
await client.set_state('hgne', on=False)

NPSClient.set_state accepts either a single outlet (identifid by its name or id) or a list of outlets. In the latter case, the NPS implementation will try to switch on/off the outlets are quickly as possible while preventing in-rush overcurrent.

Configuration files

To run as an actor, a YAML configuration file is required. An example of a valid configuration file is

nps:
    type: dli
    init_parameters:
        host: 127.0.0.1
        port: 8088
        user: admin
        password: admin

actor:
    name: lvmnps.test
    host: localhost
    port: 5672

The actor section is common to other CLU actors, and we refer the reader to the CLU documentation. An nps section is required, defining the type of the power supply (valid types are dli and netio) and the parameters necessary to initialise the relevant client class.

Running the actor

The actor can be run by executing

lvmnps -c CONFIG-FILE start [--debug]

where --debug allows to run the actor without detaching the running instance. To stop the actor use lvmnps stop.

To test the communication with the actor you can install the CLU command line interface, then execute clu and issue lvmnps status.