Tango attribute as counters

tango_attr_as_counter class allows to read a Tango number attribute as a BLISS counter.

Configuration parameters¶

class: name of the controller class to use: tango_attr_as_counter
uri: address of the Tango device
- <host>:<port>/ prefix has to be added if device is defined on another TANGO_HOST than the default one.
counters: list of counters wanted
- name (str): name to use for the BLISS counter
- attr_name (str): name of the Tango attribute
- unit (optional) (str): If specified, it will be used by BLISS instead of Tango configuration parameter unit.
- mode (optional, default:MEAN) (str): If specified, sampling mode to use to read this counter. The string corresponding to one of the SamplingMode.
- format (optional) (str): string representing the display format to use.
- index (optional) (int): index of the wanted value in case the attribute is an array.
- allow_failure (optional, default:True) (bool): raise exception or return numpy.nan upon error reading the attribute

Note

allow_failure: False is useful when you don’t want a scan interrupted by a failed reading of a tango attribute. Data will be numpy.nan in this case.

cnt.allow_failure==True means “the scan will crash if reading of cnt counter fails”

Tango attribute parameters¶

If the following parameters are defined in the attribute configuration (in Tango database), and not overwritten in YAML configuration, they will be used in BLISS:

unit (string): label used to specify units of the attribute value.
display_unit (float): conversion factor (to change unit of the attribute value) by which the raw read value is multiplied.
format (string): string representing the display format to use.

Note

display_unit is really a conversion factor. In the configuration of a Tango device server, it’s a string (eventually "None") interpreted as a float.

see https://tango-controls.readthedocs.io/en/latest/development/device-api/ds-guideline/device-server-guidelines.html for details about theses attributes.

info¶

As tango_attr_as_counter class provide a __info__() method, some info about the counter and its value can be obtained just by typing the name of the counter:

DEMO [2]: hpz_off_2
raw_value=167.193531174

Out [2]: 'hpz_off_2` Tango attribute counter info:
            device server = id16ni:20000/id16ni/hpz/metrology
            Tango attribute = Offsets
            Tango format = "%6.2f"
            Beacon unit = "mm"
            index: 2
            value: 167.19

Note

The formated and the raw values can be obtained directly via .value and .raw_value properties:

DEMO [5]: hpz_off_2.value
Out  [5]: 167.19
DEMO [6]: hpz_off_2.raw_value
Out  [6]: 167.193531174

Examples¶

Example to read ring current and beam lifetime from The Machine device server:

acs.esrf.fr:10000/ prefix is used to access Tango database of The Machine.

- class: tango_attr_as_counter
  uri: acs.esrf.fr:10000/fe/master/id42
  counters:
    - name: srcur
      attr_name: SR_Current
      mode: MEAN
      unit: mA
      format: "3.2f"
    - name: lifetime
      attr_name: SR_Lifetime
      allow_failure: False

Example to read a wago thermocouple via a Tango device server attribute:

- class: tango_attr_as_counter
  uri: id42/wcid42k/tg
  counters:
    - name: kohztc5
      attr_name: kohztc5
      mode: SINGLE
      unit: deg
    - name: kohztc6
      attr_name: kohztc6
      mode: LAST
      unit: deg
    - name: kohztc7
      attr_name: kohztc7
      unit: deg

Example of ct() with timing:

first count : 106 ms
second count : 65 ms

DEMO [2]: import   time
DEMO [3]: t0=time.time();ct(0.0001, kohztc5, flowBase, flowM2, flowM1,
                            m0m2, pptc1);print("duration=", time.time()-t0)

Tue Jul 23 15:56:13 2019

           dt[s] =          0.0 (         0.0/s)
  flowBase[l/mn] =        0.489 (      4890.0/s)
    flowM1[l/mn] =       0.8865 (      8865.0/s)
    flowM2[l/mn] =       0.7301 ( 7300.999999999999/s)
            m0m2 =      23.3999 ( 233998.99999999997/s)
    kohztc5[Deg] =         20.6 (    206000.0/s)
      pptc1[Deg] =         14.1 (    141000.0/s)

duration= 0.10665655136108398


DEMO [4]: t0=time.time();ct(0.0001, kohztc5, flowBase, flowM2, flowM1,
                            m0m2, pptc1);print("duration=", time.time()-t0)
Tue Jul 23 15:56:15 2019

            dt[s] =          0.0 (         0.0/s)
  flowBase[l/min] =       0.5111 (      5111.0/s)
    flowM1[l/min] =       0.9117 (      9117.0/s)
    flowM2[l/min] =       0.6843 (      6843.0/s)
             m0m2 =      23.3999 ( 233998.99999999997/s)
     kohztc5[Deg] =         20.6 (    206000.0/s)
       pptc1[Deg] =         14.1 (    141000.0/s)

duration= 0.06498312950134277

Tests¶

Tests files:

tests/test_counters.py
tests/test_configuration/tango_attribute_counter.yml

Tests are using:

tests/test_configuration/dummy.yml
tests/dummy_tg_server.py

pytest tests/test_counters.py -k test_tango_attr_counter