Communications¶

Various communication standards are supported by BLISS:

Serial line¶

https://en.wikipedia.org/wiki/Serial_port

Controller side¶

Example of code to declare a Serial line object within a controller:

from bliss.comm.util import get_comm, SERIAL

class Mechonics(Controller):

    def __init__(self,  *args, **kwargs):
        Controller.__init__(self, *args, **kwargs)

        # Communication
        comm_option = {'baudrate': 19200}
        self.serial = get_comm(self.config.config_dict, **comm_option)

Note

In this example, baudrate is hard-coded in controller module: it cannot be changed in YML file.

YML configuration¶

Example of YML configuration file to be used with previous controller:

-
  controller:
    class: Mechonics
    name: mechoCN30
    serial:
      url: /dev/ttyS0
    axes:
       - name: m1
         velocity: 1
         acceleration: 1
         steps_per_unit: 1
         channel: 1

Note

url field is the serial device file name and the only mandatory parameter.

Optional parameters¶

baudrate
- Usually in: 1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200
- Default: 9600
bytesize
- Usually in:
  - 7 (for true ASCII)
  - 8 (for most kinds of data, as this size matches the size of a byte)
- Default: 8
dsrdtr
- Enable hardware (DSR/DTR) flow control
- Data Set Ready / Data Terminal Ready
- Default: False
interCharTimeout
- inter byte timeout setting.
- Default: None
- NB: inter_byte_timeout in new PySerial version
parity
- Usually in: 'N': none 'O': odd, 'E': even (not really used: 'M': mark, 'S': space)
- Default: None
port
- Default: identic to url
rtscts
- Enable hardware (RTS/CTS) flow control.
- Request to Send / Clear to Send
- Default: False
stopbits
- Default: 1
timeout
- Default: 5.0
writeTimeout
- Default: None
xonxoff
- Default: False

ser2net¶

Ser2net (aka rfc2217) is a protocol to deport serial line over ethernet.

Such a remote serial line can be used in rfc2217 mode or ser2net mode.

ser2net mode allows to define the remote serial device to use in local config (considering a well configured (with control port) ser2net server)

rfc2217 mode uses the mapping “port <-> serial device” defined on the remote host in ser2net config file

-
  controller:
    class: Mechonics
    name: mechoCN30
    serial:
      url: ser2net://lidXXX:29000/dev/ttyRP11
    axes:
       - name: m1
         velocity: 1
         acceleration: 1
         steps_per_unit: 1
         channel: 1

or:

-
  controller:
    class: Mechonics
    name: mechoCN30
    serial:
      url: rfc2217://lidXXX:28001
    axes:
       - name: m1
         velocity: 1
         acceleration: 1
         steps_per_unit: 1
         channel: 1

Not declared in config¶

Serial line detached from a controller¶

Mainly for tests and debugging purpose.

Declared in config¶

To get a ser0 object usable in a BLISS session using the comm plugin.

plugin: comm
controller:
- name: ser0
  serial:
    url: /dev/ttyS0

Not declared in config¶

Example to declare a serial line directly from a BLISS shell.

from bliss.comm.util import get_comm, SERIAL

conf = {"serial": {"url": "/dev/ttyS0"}}
opt = {"parity": "N"}
kom = get_comm(conf, ctype=SERIAL, **opt)
print(kom.write_readline(b"*IDN?\n"))

Serial BLISS devices structure¶

Screenshot

TCP socket¶

TCP socket detached from a controller¶

Mainly for tests and debugging purpose.

Declared in config¶

Not declared in config¶

Example to use in BLISS shell.

conf = {"tcp": {"url": "trucmuch.esrf.fr"}}
opt = {"port":5025}
kom = get_comm(conf, ctype=TCP, **opt)
print(kom.write_readline(b"*IDN?\n"))

Controller side¶

Example to get a Socket object:

from bliss.comm.util import get_comm, TCP

class Aerotech(Controller):

    def __init__(self,  *args, **kwargs):
        Controller.__init__(self, *args, **kwargs)

    def initialize(self):
        config = self.config.config_dict
        opt = {'port':8000, 'eol':'\n'}
        self._comm = get_comm(config, ctype=TCP, **opt)

other example:

class PressureTransmitter(object):
    def __init__(self, name, config):
        self.comm = get_comm(config, baudrate=9600)

YML configuration¶

Example of YML configuration file to be used with previous controller:

- class: aerotech
    name: Аэрофлот
    tcp:
        url: 160.103.99.42
    axes:
       - name: rot
         aero_name: X
         velocity: 10.1
         acceleration: 25.0
         steps_per_unit: 6789.444

Mandatory parameters¶

url: It can be an IP address or a fully qualified name.
- examples:
  - 160.103.14.92
  - zorglub.esrf.fr
port: It’s the target host’s port to use.
- example:
  - 5025

Optional parameters¶

port¶

Default:

timeout¶

Default: 5.0

eol¶

The eol parameter that can be defined in config or in get_comm() function is used by socket to read lines. It is not sent by the write*() functions and therefore a terminaison character must be added in all messages sent to a device.

Default: \n

GPIB¶

There are various ways to communicate with Gpib devices: * Gpib PCI board - localy if BLISS is run on the same computer than the Gpib driver - remotely if BLISS is run on another computer * Gpib ethernet device: Enet box

Exmaple of gpib communication with PCI gpib board and tango device server:

gpib:
  url: tango_gpib_device_server://id42/gpib_lid421/0
  pad: 13
  timeout: 10.

Exmaple of gpib communication with enet device:

gpib:
  url: enet://gpibid42a.esrf.fr
  pad: 15
  timeout: 3.

UDP Socket¶

TODO

SCPI¶

TODO

modbus¶

TODO