Universal Signal Waveform Acquisition & Generation

A GUI-based software for controlling oscilloscopes and signal generators from a variety of vendors. Supported devices include:

• Keysight Technologies DSOX1102A
• TiePie engineering Handyscope HS3 & HS5
• Tektronix TBS1072C
• Hantek 6022BE/BL
• Tektronix AFG1022

Most prominent features are:

• Realtime display of oscilloscope measurement data (in both time and frequency domain)
• Preview of signal generator output according to the current settings
• CSV compatibility - load arbitrary data from file into signal generator & save displayed oscilloscope measurement data to file
• Hot plugging support - devices can be inserted or removed during runtime
• Runs on both Linux and Windows

Extending the software

You can add more signal generators & oscilloscopes from other vendors to the collection of compatible devices without much of a hassle by following these 5 steps:

1. Have a look at what functionalities you need: gen_properties.py & osc_properties.py

First determine, whether the device you want to add is of the type signal generator (from now on abbreviated simply as generator) or oscilloscope. Then, open the respective device_properties/...properties.py file. This file contains the entire collection of methods and properties corresponding to that device type across all vendors & models.

If the properties of the device you’re about to add happen to be a subset of this collection, you can skip to step 2. Otherwise, you’ll have to add new lines of code here.

You’ll notice that each device property requires implementation of two Python functions. The first one always carries the @QtCore.Slot decorator, this is the function invoked by frontend. In order not to block the GUI thread, this function will then invoke the second, similarly named function in its own thread. Depending on the value parameter passed by frontend, the ..._thread function will then access the getter and / or setter for that property.

You can use the existing functions as a template to implement the missing ones. Just keep in mind that frontend always passes the value parameter as string, so make sure to cast it properly before use.

2. Implement the interface to the hardware: generators/ & oscilloscopes/

Have a look at the devices/device.py file and closely examine both the classes (Device & Channel) featured in that file. Afterwards, do the same with either devices/generator.py or devices/oscilloscope.py, depending on the type of device you’re about to add.

When you got a grasp of the concepts, create a new Python file for your device in either the devices/generators/ or the devices/oscilloscopes/ subdirectory. In that file, create one class that inherits from Generator or Oscilloscope, respectively. Then, add a second class that inherits from GenChannel or OscChannel, respectively.

Both of the classes you’ve added in the newly created file must implement all abstract methods, as well as the desired subset of getters & setters invoked in the ..._thread functions of device_properties/...properties.py. You can use the existing ...gen.py & ...osc.py files as guidelines on how to use the provided class variables, mutexes, methods, etc.

3. Enable the Device Manager to create objects of your new interface: device_manager.py

In order to let the Device Manager create instances of the newly implemented interface to your device, you’ll need to update device_manager.py. In there, look for the _on_add_device method.

...
elif device_vendor == 'Tiepie':
    added_devices.append(TiepieOsc(..., self._device_stopped))
    added_devices.append(TiepieGen(...))
elif device_vendor == 'Keysight':
    added_devices.append(KeysightOsc(..., self._device_stopped))
elif device_vendor == 'Tektronix':
    added_devices.append(TektronixGen(...))
...

Add another elif case for your device’s vendor where you append your interface to added_devices. Remember to pass self._device_stopped to your constructor if it’s an oscilloscope.

4. Make the USB Daemon recognize your device: usb_device_daemon.py

The USB Daemon monitors the USB ports of the computer for events caused by plugging devices in or out. If one of those devices happens to be a generator or oscilloscope supported by the application, the Daemon notifies the Device Manager which updates its device list accordingly.

If your device isn’t an actual physical device that needs to be connected via USB, you can skip to step 5. Otherwise, you’ll have to add new lines of code in usb_device_daemon.py.

Look for the _event_handler method.

...
# get all available information on the device vendor
...

# check which vendor's device was plugged in
# and invoke "new device" callback function with corresponding parameters

if 'TiePie engineering' in dev_vendor_info:

    ...

elif 'Keysight_Technologies' in dev_vendor_info:

    ...

elif 'TEKTRONIX' in dev_vendor_info:

    ...

# for all VISA devices on Windows only
elif 'IVI Foundation, Inc' in dev_vendor_info and platform == 'win32':
...

Add another elif case for your device’s vendor similar to the other cases.

Remember to do these two updates within the case 'IVI Foundation, Inc' in dev_vendor_info and platform == 'win32' if your device uses the VISA interface, because it won’t be recognized on Windows otherwise:

• Add the vendor’s name to the known_visa_vendors list
• Map the new entry in known_visa_vendors to the Manufacturer ID by extending the following snippet with another elif:

...
# prettify the list of all currently connected devices of this vendor
...
for dev in dev_list_raw:

    ...
    if manufacturer == 'KEYSIGHT TECHNOLOGIES':
        visa_vendor = 'Keysight'
    elif manufacturer == 'TEKTRONIX':
        visa_vendor = 'Tektronix'
...

5. Design the GUI’s settings bar for your device and its channels: qml/devices/generators/ & qml/devices/oscilloscopes/

When selecting an entry in the device list during application runtime, frontend attempts to load two QML files, one for the overall device settings and one for the channel-specific settings. These two files need to be located inside of the qml/devices/generators/ or qml/devices/oscilloscopes/ directory, depending on the device type. It is of great importance that the naming scheme for the files follows this format, otherwise frontend won’t be able to find the correct file:

• Vendor_Modelname_DEVICE.qml for the device file
• Vendor_Modelname_CHANNEL.qml for the channel file

Create both files in the correct directory and then proceed to fill them with appropriate content. You can use the existing files as templates in order to do that. Basically you have to:

• Set the GridLayout’s number of columns to the number of available settings
• Create one text label for each setting describing what it does
• Create one widget (ComboBox, TextField, CheckBox or Button) for each setting which invokes the corresponding @QtCore.Slot function from device_properties/...properties.py
• Adjust the reload...Settings function so that all property getters are called once. Remember that for comboboxes, you only need to call the ..._avail function, since it will automatically invoke the getter for the current value
• Create one on... function for each value that is returned from backend after invoking property getters. Use the passed value parameter to update the corresponding widget’s current placeholder text, index selection, etc.

Summary

1. Check and potentially extend device_properties/...properties.py
2. Create interface file in devices/.../ with 2 classes inheriting from either Generator & GenChannel or Oscilloscope & OscChannel.
3. Extend _on_add_device in device_manager.py
4. Potentially extend _event_handler in usb_device_daemon.py
5. Create Vendor_Modelname_DEVICE.qml & Vendor_Modelname_CHANNEL.qml in qml/devices/.../