Vacuubrand library

This library is used to control basic features of a Vacuubrand controller.

It is composed of a core library, an optional simulator and an optional tango device server.

So far only the DCP 3000 is supported.

Installation

From within your favorite python environment type:

$ pip install vacuubrand

Library

The core of the vacuubrand library consists of DCP3000 object. To create a DCP3000 object you need to pass a communication object.

The communication object can be any object that supports a simple API consisting of two methods (either the sync or async version is supported):

• write_readline(buff: bytes) -> bytes or
• write(buff: bytes) -> None or

Usually you end up using a connio.connection_for_url() object. Here is how to connect to a DCP 3000 controller:

import asyncio
from connio import connection_for_url
from vacuubrand.dcp3000 import DCP3000


async def main():
    # could also be a socket bridge: 'serial-tcp://<host>:<port>'
    comm = connection_for_url('serial:///dev/ttyS0')
    dcp = DCP3000(comm)

    print(await dcp.pressure())


asyncio.run(main())

Serial line

To access a serial line based DCP 3000 device it is strongly recommended you spawn a serial to tcp bridge using ser2net or socat

Assuming your device is connected to /dev/ttyS0 and the baudrate is set to 19200, here is how you could use socat to expose your device on the machine port 5000:

socat -v TCP-LISTEN:8500,reuseaddr,fork file:/dev/ttyS0,rawer,b19200,cs8,eol=10,icanon=1

The equivalent line in ser2net config file would be:

8500:raw:0:/dev/ttyR15:19200 8DATABITS NONE 1STOPBIT

It might be worth considering starting socat or ser2net as a service using supervisor or circus.

Simulator

A DCP 3000 simulator is provided.

Before using it, make sure everything is installed with:

$ pip install vacuubrand[simulator]

The sinstruments engine is used.

To start a simulator you need to write a YAML config file where you define how many devices you want to simulate and which properties they hold.

The following example exports 2 hardware devices. The first is a minimal configuration using default values and the second defines some initial values explicitly:

# config.yml

devices:
- class: DCP3000
  package: vacuubrand.simulator
  transports:
  - type: serial
    url: /tmp/dcp3000-1

To start the simulator type:

$ sinstruments-server -c ./config.yml --log-level=DEBUG
2020-07-02 12:18:45,065 INFO  simulator: Bootstraping server
2020-07-02 12:18:45,065 INFO  simulator: no backdoor declared
2020-07-02 12:18:45,065 INFO  simulator: Creating device DCP3000 ('DCP3000')
2020-07-02 12:18:45,067 INFO  simulator: Created symbolic link "/tmp/dcp3000-1" to simulator pseudo terminal '/dev/pts/7'
2020-07-02 12:18:45,067 INFO  simulator.DCP3000[/tmp/dcp3000-1]: listening on /tmp/dcp3000-1 (baud=None)

(To see the full list of options type sinstruments-server --help)

You can access it as you would a real hardware:

$ miniterm.py -e --eol CRLF /tmp/dcp3000-1
IN_PV_1
1004.1 mbar

or using the library:

$ python
>>> from connio import connection_for_url
>>> from vacuubrand.dcp3000 import DCP3000
>>> conn = connection_for_url("serial:///tmp/dcp3000-1")
>>> dcp = DCP3000(conn)
>>> print(await dcp.actual_pressure())
1004.1

Tango server

A tango device server is also provided.

Make sure everything is installed with:

$ pip install vacuubrand[tango]

Register a Vacuubrand tango server in the tango database:

$ tangoctl server add -s Vacuubrand/test -d DCP3000 test/dcp3000/1
$ tangoctl device property write -d test/dcp3000/1 -p url -v "/dev/ttyS0"

(the above example uses tangoctl. You would need to install it with pip install tangoctl before using it. You are free to use any other tango tool like fandango or Jive)

Launch the server with:

$ Vacuubrand test