Measurement Tool Box functions

In the following a simple doc string representation of all tool box functions are displayed. These functions can be used to simplify your own measurement plugin. You can simply import it and save an instance of this class and reference it. Or more conveniently, your measurement plugin can inherit the tools class and make every member of tools a member of your plugin. To see how this works see in the tutorial section the chapter Add a new measurement.

class measurement_plugins.forge_tools.tools(framework=None, event_loop=None)

Some tools for forging your own measurement plugins. It needs the framework and the event_loop object

capacitor_discharge(device_dict, relay_dict, Setterminal=None, terminal=None, do_anyway=False)

This function is rather special for SQC. It checks if the capacitor of the decouple box is correctly discharged

Parameters

• device_dict -- Device object

• relay_dict -- Relay object

• Setterminal -- set terminla command

• terminal -- terminal Front or back

• do_anyway -- Do it anyway

Returns

Bool

change_value(device_dict, order, value='')

This function simply sends a command to a device.

Parameters

• device_dict -- The device object

• order -- The command to be send

• value -- The value for the command

Returns

None

change_value_query(device_dict, order, value='', answer='1', ignore_answer=False)

This function query a command to a device and waits for a return value and compares it with the answer statement, if they are the same a true is returned otherwise a None

Parameters

• device_dict -- Device object

• order -- The command to be send

• value -- The value

• answer -- The answer it should have

• ignore_answer -- Should the answer be ignored

Returns

Answer or None

check_compliance(device, compliance=None, command='get_read')

This function checks if the current compliance is reached.

Parameters

• device -- The device object

• compliance -- The compliance value

• command -- The command to check

Returns

Bool

config_setup(device, commands=(), delay=0.0)

This function configures the setup for a specific measurement. Commands is a list of tuples, containing (command, values) if no value is defined only command will be send

Parameters

• device -- The device object

• commands -- A list of tuples with (command, values). If no value is defined only command will be send

• delay -- The delay between each command

Returns

None

do_ramp_value(resource, order, voltage_Start, voltage_End, step, wait_time=0.05, compliance=None, set_value=None)

This functions ramps a value from one point to another. It actually sends the commands to the device

Parameters

• resource -- Device object

• order -- The command to set tje voltage

• voltage_Start -- Start point

• voltage_End -- End point

• step -- Stepsize

• wait_time -- Wait between values

• compliance -- Compliance, if None the compliance check will be skipped

• set_value -- If you want to set a value each interation in the state machine (must be a callable function)

Returns

True

query_device(device_dict, command)

This command just sends the command directly to the device, and waits for an answer. Warning it is not recommended to use this function. Use this function only if you must! Use query_value instead

Parameters

• device_dict -- Dictionary of the device

• command -- The command you want to send to the device

Returns

Return string from the device

query_value(device_dict, order, value='')

This function simply queries a command to a device.

Parameters

• device_dict -- The device object

• order -- The command to be send

• value -- The value for the command

Returns

the return from the device

ramp_value(min_value, max_value, deltaI)

Generates a list of values in the defined stepsize between the and min/max values

Parameters

• min_value -- Start point of list

• max_value -- End point of list

• deltaI -- Stepsize between points

Returns

List

ramp_value_log10(min_value, max_value, deltasteps)

This function takes a min and max value, deltasteps and generates a list of values in log10 format with each deltasteps values per decade

Parameters

• min_value -- Start value

• max_value -- End Value

• deltasteps -- How many steps per decade

Returns

List

refine_ramp(ramp, start, stop, step)

Refines a ramp of values eg. for IVCV, in the beginning it makes sense to refine the ramp

Parameters

• ramp -- A list of values

• start -- Start point of refinement (must be inside of ramp)

• stop -- End point of refinement (must be inside of ramp)

• step -- The step size of the refinement

Returns

Updated list

send_to_device(device_dict, command, seperate=None)

This command just sends the command directly to the device. Warning it is not recommended to use this function. Use this function only if you must! Use change_value instead.

Parameters

• device_dict -- Dictionary of the device

• command -- The command you want to send to the device

• seperate -- if specified, the string gets split and the command will be send separately at the separator

Returns

None

steady_state_check(device, command='get_read', max_slope=0.001, wait=0.2, samples=4, Rsq=0.95, compliance=5e-05, do_anyway=False, check_compliance=True, iteration=7, wait_time_factor=1.0)

This function reads values from a device and fits a linear fit to it. If the fit exceeds a maximum slope it waits a specified time and does ot again. If the slope condition is not reached after a few attempts the function returns False. Otherwise it returns True and indicates a equilibrium has been reached.

Parameters

• device -- The device object which should be queried

• command -- The command which should be queried

• max_slope -- The maximum slope, x-axis is measured in seconds, so a slope of 1e-9 is a change of 1n per second

• wait -- How long to wait between attempts

• samples -- How many samples should be used

• Rsq -- Minimum R^2 value

• compliance -- The compliance value which the value should not exceed

• do_anyway -- If the result should be ignored

• check_compliance -- If the program should check the compliance value

• iteration -- number of iterations

• wait_time_factor -- factor the waiting time is increased with every iteration

Returns

Bool - True means steady state reached

stop_measurement()

Sends a signal to the framework to stop every measurement

VCW - Visa Connect Wizard

In the following a simple doc string representation of all VCW functions are displayed. These functions can be used to simplify your own measurement plugin. You can simply import it and save an instance of this class and reference it. Or more conveniently, your measurement plugin always gets a working instance of it in the form of the framework variables object. With it you can easy and savely send your devices any kind of command directly.

Note

Usually you are using a wrapper function of the Measurement Tool Box functions for this functions!

XYZ-Stage Control Class

The XYZ-Stage Control Class is a core feature of COMET it allows you to safely operate any configured automated table. An instance is generated on start up -if a stage is configured- in the Framework variables. It features several move functions which has build in the functionality to first move down the stage and then move to another location and if in position move the table up again. This prevents scratches on e.g. silicon sensors when contacted with needles.

Furthermore, it checks the position of the stage to make sure the table is always on the correct location. If not an error will be raised in the COMETs internal error handling system.

Switching System Control Class

The Switching System Control Class gives you functions to safely operate a switching system. An instance is generated on start up in the Framework variables. It has the ability to cope with lots of different variants of switching systems. In the following section the needed config files and a how to, will be explained.

First of all you need at least one switching device configured. This device needs an entry Device_type: Switching relay so that COMET knows that this device is a switching capable device. The other parameters of this device are of the same type as any other measurement device.

The other thing you need are configs to tell COMET what to switch. Therefore, you need a config YAML file in your project with the Settings_name: Switching entry and Device_type: Switching relay. This is followed by the entry Switching_Schemes. In it are the different measurement types to switch followed by the name of the device and then the switching relays which need to be closed.

To clarify what I mean with that see an example:

---
Settings_name: Switching
Device_type: "Switching relay"
Switching_Schemes:
  IV: # Name of the switching configuration
    HVSwitching: # Name or Alias of a Switching device
      - A1  # relay to switch
      - B1
      - C2
  Rpoly:
    HVSwitching: # Name or Alias of a Switching device
      - A1
      - B1
      - C1

    LVSwitching: # Name or Alias of a Switching device
      - 1C05
      - 1C06

Here two switching schemes are defined. IV and Rpoly. For IV only the device/alias HVSwitching will be switched with the relays: A1,B1,C2. For Rpoly not only HVSwitching also the switching device LVSwitching will be switched.

If you have configured your setup like this it is fairly easy to switch to the measurement configuration IV. Just call the function: switch_to_measurement("IV") and the class will handle the switching on its own.

Important

The class checks if the switching has been done correctly. If your switching of the device does not match the intended switching an error will be raised and the user will be informed.

Some devices have the ability to do a device exclusive switching, so all switching logic is done by the device. If you want to use this device exclusive switching, the device config file must have the entry: device_exclusive_switching: True Otherwise you can set it False or not state it at all. For non exclusive switching devices the switching logic will be done via the switching class.

Note

In future releases there will be a config option to decide BBM or MBB. Currently it is hard coded to BBM since this is the recommended way to do it.