Creating Custom Instrument Profiles in PyTestLab¶

This tutorial will guide you through the process of creating a custom instrument profile for PyTestLab. Instrument profiles are YAML files that define the capabilities and command mappings for a specific instrument, allowing PyTestLab to communicate with it effectively.

1. The Basic Structure of a Profile YAML File¶

An instrument profile is a YAML file that contains all the information PyTestLab needs to control an instrument. The top-level keys in the YAML file define the instrument's identity and its various components.

Here is a minimal example of a profile for a fictional power supply:

The main keys are:

• manufacturer: The name of the instrument manufacturer.
• model: The model number of the instrument.
• type: The instrument type (e.g., PowerSupply, Oscilloscope, Multimeter). This determines which base class PyTestLab will use.
• settings: Defines the instrument's configurable settings.
• commands: Defines the actions the instrument can perform.

2. Defining Instrument Settings¶

The settings section maps high-level attribute names (like voltage) to the corresponding SCPI commands. Each setting can have a query to read the value and a command to set it.

In our example:

settings:
  voltage:
    query: "VOLT?"
    command: "VOLT {value}"
  current_limit:
    query: "CURR?"
    command: "CURR {value}"

When you access instrument.voltage, PyTestLab sends the VOLT? query. When you set instrument.voltage = 5.0, it sends VOLT 5.0.

3. Defining Commands¶

The commands section defines methods that control the instrument. These are simple, parameter-less actions.

In our example:

commands:
  enable_output:
    command: "OUTP ON"
  disable_output:
    command: "OUTP OFF"

Calling instrument.enable_output() will send the OUTP ON command to the instrument.

4. Defining Parameters¶

For more complex interactions that require arguments, you can use the parameters section. This is useful for commands that take arguments but don't fit the simple setting = value model.

For example, to set the voltage and current on a specific channel:

parameters:
  set_channel_config:
    command: "INST:NSEL {channel}; VOLT {voltage}; CURR {current}"

You could then call instrument.set_channel_config(channel=1, voltage=3.3, current=0.5).

5. Loading and Using the New Profile¶

Once you have created your profile YAML file, you can load it in PyTestLab and connect to your instrument. You can use a simulated backend for testing without a physical instrument.

Conclusion¶

You have now learned the basics of creating a custom instrument profile in PyTestLab. By defining the structure, settings, commands, and parameters in a YAML file, you can extend PyTestLab to support a wide range of instruments.