mpylab.device.powermeter module

mpylab.device.powermeter module.

class mpylab.device.powermeter.POWERMETER(SearchPaths=None)

Bases: DRIVER

Child class for all py-drivers for power meters.

The parent class is mpylab.device.driver.DRIVER.

The configuration template for this device class is:

conftmpl={'description':
             {'description': str,
              'type': str,
              'vendor': str,
              'serialnr': str,
              'deviceid': str,
              'driver': str},
            'init_value':
                {'fstart': float,
                 'fstop': float,
                 'fstep': float,
                 'gpib': int,
                 'virtual': strbool,
                 'nr_of_channels': int},
            'channel_%d':
                {'name': str,
                 'filter': int,
                 'unit': str,
                 'resolution': int,
                 'rangemode': str,
                 'manrange': float,
                 'swr1': float,
                 'swr2': float,
                 'sensor': str,
                 'interpolation': str,
                 'file': _file_source}}

The meaning is:

• Section description

  • description: string describing the instrument

  • type: string with the instrument type (here: POWERMETER)

  • vendor: string ddescribing the vendor/manufactor

  • serialnr: string with a unique identification

  • deviceid: string with an internal id

  • driver: filename of the instrument driver (.py, .pyc, .pyd, .dll)

• Section init_value

  • fstart: lowest possible frequency in Hz of the device

  • fstop: highest possible frequency in Hz of the device

  • fstep: smallest frequency step in Hz of the device

  • gpib: GPIB address of the device

  • virtual: 0, false or 1, true. Virtual device are usefull for testing and debugging.

  • nr_of_channels: indicates how many channel sections follow

• Section channel_%d (%d may be 1, 2, …)

  • name: a string identifying the channel.

  • filter: device specific integer specifying the filter used

  • unit: a string containing the unit of the returned power readings. However, scuq will ignore dB-settings, and the returned power will contain the unit anyway.

  • resolution: device specific integer giving the resolutuion of the returned power

  • rangemode: ‘auto’, ‘autoonce’, or ‘manual’

  • manrange: fload specifiing the range in manual range mode

  • swr: VSWR of the measured two port. May be used in uncertainty calculations

  • sensor: string specifying the used power sensor. May be used in uncertainty calculations.

Parameters:

SearchPaths (sequence of path-like, optional) – Directories searched for device INI files and referenced limit data.

GetData()

Read one power value including mismatch uncertainty.

Returns:

(status, power) where power is a scuq.Quantity, or None if communication failed.

Return type:

tuple

GetDataNB(retrigger=False)

Read power through the non-blocking driver interface.

The base implementation delegates to blocking GetData().

Parameters:

retrigger (bool or str, optional) – Trigger a new acquisition after reading when true or equal to "on".

Returns:

(status, power) where power is a scuq.Quantity when available.

Return type:

tuple

GetFreq()

Read the sensor correction frequency.

Returns:

(status, frequency) with the value in hertz, or None when unavailable.

Return type:

tuple

GetSafetyLimit(what)

Return a named safety limit at the current frequency.

Parameters:

what (str) – Limit-channel name, for example MAXIN.

Returns:

(0, limit) with an interpolated scuq.Quantity, or (-1, None) if the limit or current frequency is unavailable.

Return type:

tuple

Init(ini=None, channel=None, ignore_bus=None)

Initialize the power meter and its optional safety limits.

Parameters:

• ini (path-like or file-like, optional) – Device configuration source.

• channel (int or str, optional) – Initial measurement channel.

• ignore_bus (bool or None, optional) – Bus policy. None selects normal hardware communication.

Returns:

Device status; zero indicates success.

Return type:

int

RANGE = ('MANUAL', 'AUTO', 'AUTOONCE')

SetFreq(freq)

Set and read back the sensor correction frequency.

Parameters:

freq (float) – Requested frequency in hertz.

Returns:

(status, frequency) with the read-back value in hertz.

Return type:

tuple

Trigger()

Trigger a single power measurement.

Returns:

Device status; zero indicates success.

Return type:

int

Zero(state='on')

Set the power-meter zero-correction state.

Parameters:

state (str or bool-like, optional) – "on" enables zero correction; every other value disables it.

Returns:

(status, 0).

Return type:

tuple of int

ZeroCorrection = ('OFF', 'ON')

conftmpl = {'channel_%d': {'file': <function _file_source>, 'filter': <class 'int'>, 'interpolation': <class 'str'>, 'manrange': <class 'float'>, 'name': <class 'str'>, 'rangemode': <class 'str'>, 'resolution': <class 'int'>, 'sensor': <class 'str'>, 'swr1': <class 'float'>, 'swr2': <class 'float'>, 'unit': <class 'str'>}, 'description': {'description': <class 'str'>, 'deviceid': <class 'str'>, 'driver': <class 'str'>, 'serialnr': <class 'str'>, 'type': <class 'str'>, 'vendor': <class 'str'>}, 'init_value': {'fstart': <class 'float'>, 'fstep': <class 'float'>, 'fstop': <class 'float'>, 'gpib': <class 'int'>, 'nr_of_channels': <class 'int'>, 'virtual': <function strbool>}}

get_standard_mismatch_uncertainty()

Calculate relative standard uncertainty caused by mismatch.

swr1 and swr2 are read from the active channel configuration. The result is on a linear relative scale. An expanded uncertainty is obtained by applying the desired coverage factor.

Returns:

Relative standard uncertainty for a U-shaped phase distribution.

Return type:

float

Raises:

ValueError – If either configured VSWR is non-finite or smaller than one.

update_internal_unit(ch=None, unit=None)

Select the internal unit used to interpret power readings.

Parameters:

• ch (int, optional) – Channel number for multichannel devices, starting at one. The active channel is used when omitted.

• unit (str or scuq.units.Unit, optional) – Device-side unit. The current internal unit is retained when omitted.

• posibilities:: (The table shows the) – Unit SCPI notation Watt W dB DB dBm DBM dBuV DBUV