driver/pyvisa: extend Test and Measurement equipment support by Sabolik · Pull Request #1835 · labgrid-project/labgrid

Sabolik · 2026-03-04T09:59:12Z

Description

Main purpose:

Extend generic support for T&M instruments (SCPI based test & measurement equipment) using already existing pyvisa driver with appropriate backend (e.g. pyvisa-py)
Add pyvisa remote access by introducing an agent wrapper module.
Extend pyvisa driver with the option to select specific resource type (e.g. INSTR/SOCKET).
Add remote client support.
Introduce the tminstrument driver as high-level wrapper for low-level drivers, (pyvisa, usbtmc), with PowerProtocol support. Potentially replacing the standalone usbtmc driver.
Add backend support for various laboratory instruments, e.g. convenient command wrapper for SCPI commands.

The implementation was tested only by using it with devices on our lab environment, both locally and remotely for following interfaces:

TCPIP INSTR
TCPIP SOCKET
ASRL INSTR
USB INSTR

Checklist

Documentation for the feature
Tests for the feature

The arguments and description in doc/configuration.rst have been updated

Add a section on how to use the feature to doc/usage.rst

Add a section on how to use the feature to doc/development.rst

PR has been tested

Man pages have been regenerated

Emantor

remote: client: add remote pyvisa access needs a commit message explaining why the change is done.

I wonder if the current backend() calling mechanic can't be simplified to be more explicit instead of inspecting the imported module backend and calling functions on it again. It looks like we are cramming a lot of calls through the backend() function, while we have the explicit module with function definitions for each instrument. Why not call the functions on the module directly?

Emantor · 2026-03-04T10:09:28Z

-    def query(self, cmd):
-        return self.proxy.query(self.device_identifier, self.pyvisa_resource.backend, cmd)
+    def query(self, cmd, timeout=TIMEOUT_DEFAULT):
+        return self.proxy.query(self.device_identifier, self.pyvisa_resource.backend, cmd, timeout).rstrip()


This rstrip() is added here, can you add a description to the commit why it was added?

The termination might differ among instruments. Another option might be to properly set the read_termination parameter of the resource, but I would rather keep rstrip for simplicity.

Emantor · 2026-03-04T10:10:50Z

 from ..util.agentwrapper import AgentWrapper
 from .common import Driver

+TIMEOUT_DEFAULT = 2000  # Default timeout for visa operations in ms


I think I prefer having the default in the keyword arguments i.e. def command(self, cmd, timeout=2000) and we also want a docstring which documents this to be in miliseconds.

Agree. Thanks

Emantor · 2026-03-04T10:13:48Z

    Args:
        type (str): device resource type following the pyVISA resource syntax, e.g. ASRL, TCPIP...
-        url (str): device identifier on selected resource, e.g. <ip> for TCPIP resource
+        url (str, default=''): optional device identifier on selected resource, e.g. <ip> for TCPIP resource


Why can the default be changed to an empty string here? Is this not mandatory?

No, it is optional. Some interfaces are fully specified by the type parameter, e.g. serial devices like ASRL/dev/ttyACM0.

Emantor · 2026-03-04T10:14:58Z


    type = attr.ib(validator=attr.validators.instance_of(str))
    url = attr.ib(default="", validator=attr.validators.instance_of(str))
+    resource = attr.ib(default="INSTR", validator=attr.validators.instance_of(str))


If there is a finite amount of resource type definitions we might want to extend the validator, but this can be added later.

It seems to be fixed based on the VISA documantation, but honestly I am not familiar with all of them, so I am not sure what are the consequences. But the most common are INSTR and SOCKET and RAW, might be good idea to create a validator for them.

Sabolik · 2026-03-05T14:54:03Z

@Emantor thanks a lot for review, all comments should be fixed now.

Regarding backend() implementation:

I think there is a direct call, once you call for it and proper module is imported based on identification (first call).
There is an option to list all backend methods available in case None is passed instead of backend command
I pushed a minor change fixing overwriting _self.backend module each time backend is called.

threexc · 2026-03-10T12:58:36Z

@Sabolik thanks for doing this work. Do you have some example device names you've tested this with? I have an SDG1032X waveform generator which supports VISA that I may try it out on.

Sabolik · 2026-03-10T13:53:02Z

@Sabolik thanks for doing this work. Do you have some example device names you've tested this with? I have an SDG1032X waveform generator which supports VISA that I may try it out on.

it should be pretty generic from the SCPI commanding point of view. There might be (optionally) backend implemented as SCPI convenient commands wrapper. Few equipment are already supported, listed here.

Let me give you few possible ways how to access the equipment (USB rigol DM3068 as example):

Directly (just for explanation purpose):

Usage example:

## bind target to driver directly in code

from labgrid.resource.pyvisa import PyVISADevice
from labgrid.driver.tminstrument import TMInstrument
from labgrid import Target

t = Target('example')
# equipment connected via USB
PyVISADevice(t, name=None, type='USB0', url='6833::3220::DM3O224500792::0', backend='@py')

# using low-level pvisa driver
from labgrid.driver.pyvisadriver import PyVISADriver
visa_driver = PyVISADriver(t, name="tm-inst-visa-rigol-dmm")
t.activate(visa_driver)
visa_driver.identify()
# equivalent to
visa_driver.query('*IDN?')

# or using of high level driver (TMInstrument) with VISA backend (Reomended way)
from labgrid.driver.tminstrument import TMInstrument
tm_inst_driver = TMInstrument(t, name="tm-inst-visa-rigol-dmm")
t.activate(tm_inst_driver)
tm_inst_driver.identify()
# equivalent to
tm_inst_driver.query('*IDN?')

Bind resource to drivers via environment configuration:

Config (config_visa.yaml):

targets:
  main:
    resources:
    - PyVISADevice:
        name: dmm-rigol
        type: "USB0"
        url: "6833::3220::DM3O224500792::0"
        backend: "@py"
    drivers:
    - PyVISADriver:
        name: driver-visa-rigol-dmm
        bindings: { pyvisa_resource : 'dmm-rigol'}
    - TMInstrument: 
          bindings: { inst : 'driver-visa-rigol-dmm' }
          name: 'tm-inst-visa-rigol-dmm'

Usage example:

## bind target to driver using config file

from labgrid import Environment
env = Environment('config_visa.yaml')
targets=env.get_target()

inst_visa_rigol_psu = targets.get_driver(TMInstrument, name="tm-inst-visa-rigol-dmm")
inst_visa_rigol_psu.identify()
# equivalent to
inst_visa_rigol_psu.query('*IDN?')

You may control the device also remotely using labgrid-client, if resources are properly exported, see example here

Emantor · 2026-03-19T14:44:30Z

@threexc Did you find some time to test this?

threexc · 2026-03-19T19:30:46Z

@threexc Did you find some time to test this?

I've been looking at it. I was able to do a basic test on my side with my SDG1032X and confirm it can communicate:

(venv) tgamblin@outpost:~/workspace/git/labgrid-power-up$ labgrid-client -c workbench/wb-client.yaml inst identify --name 'tm-inst-sdg1032x'
Selected role main and place workbench from configuration file
/usr/lib/python3/dist-packages/pyvisa_py/protocols/usbtmc.py:116: UserWarning: Unexpected MsgID format. Consider updating the device's firmware. See https://github.com/pyvisa/pyvisa-py/issues/20Expected message id was 2, got 46.
  warnings.warn(
Siglent Technologies,SDG1032X,SDG1XDFQ6R5627,1.01.01.33R

This is with the following exporter config for the device:

  wb-generator-1:
    cls: 'PyVISADevice'
    type: 'USB0'
    url: '0xF4EC::0x1103::SDG1XDFQ6R5627::0'
    backend: '@py'

and a client config like:

      - PyVISADriver:
          name: 'sdg1032x-driver'
          bindings:
            pyvisa_resource: 'wb-generator-1'
      - TMInstrument:
          name: 'tm-inst-sdg1032x'
          bindings:
            inst: 'sdg1032x-driver'

Seems reasonable enough to me. My only major issue with this PR is that there are examples in the commits but not really any updates to the docs? It would be good to have decent examples of the exporter and client configs, along with example commands to run (the ones in some of the commit messages that I've been pointed at are probably enough).

@Sabolik, can you add another commit to reflect that?

gastmaier · 2026-03-24T07:59:31Z

        assert isinstance(cmd, str)
        cmd = b2s(cmd.encode("ASCII") + b"\n")
-        res = s2b(self.wrapper.usbtmc(self.index, cmd, read=True))
+        res = s2b(self.wrapper.usbtmc(self.dev_index, cmd, read=True))


is any change in this file really needed?

It seems to be needed. The reason is that the same attribute is used by power resource as power port identification. Power resource is directly supported by tminstrument driver while conflicting with low-level usbtmc driver (usbtmc device identification)

actually not needed. There was conflict between power driver implementation using USBTMC resource used locally in past in our lab, but this is not part of this PR.

Signed-off-by: Hermann Leinweber <hermann.leinweber@erweka.com>

The agent supports remote access to instruments connected locally, e.g. via USB or a serial port. The pyVISA library also supports USBTMC devices; therefore, the dedicated USBTMC driver can be replaced by pyVISA. Signed-off-by: Martin Sabol <martin.sabol@seznam.cz>

Introduce NetworkPyVISADevice for remote access to pyVISA resources. Use an agent wrapper to support both local and remote resource access. Signed-off-by: Martin Sabol <martin.sabol@seznam.cz>

It has been replaced by visa_instrument.py agent. Signed-off-by: Martin Sabol <martin.sabol@seznam.cz>

Allow users to configure the timeout for resource I/O operations while keeping the original 2-second default. Remove possible termination characters. This might differ among various instruments/manufacturers. Signed-off-by: Martin Sabol <martin.sabol@seznam.cz>

Supports VISA resource types, see https://www.ni.com/docs/en-US/bundle/ni-visa/page/visa-resource-types.html?srsltid=AfmBOopVXVhQ0TRR_zFesL1Bj90aKB7_MFSa3nbKvgZ47RRAbv-WIlAE Defaults to INSTR resource type. If a raw socket is used (e.g., TCPIP::IPaddress::Port::SOCKET), set the termination character. Always clear the resource after it is opened. Signed-off-by: Martin Sabol <martin.sabol@seznam.cz>

Provides a common interface for SCPI-compatible instruments. The instrument can be controlled using different low-level drivers, such as PyVISA, USBTMC, or custom backends. An appropriate command backend can be mapped within the driver for convenient instrument control. PowerProtocol is supported. Signed-off-by: Martin Sabol <martin.sabol@seznam.cz>

Add a method to the tminstrument driver for querying iterables, such as lists of readings. Signed-off-by: Martin Sabol <martin.sabol@seznam.cz>

Add tminstrument driver access using a remote labgrid client. Following functions are available: - command: send a command to the instrument - query: send a command and read the response from the instrument - query_iterable: send a command and read the response from the instrument as a list of floats usage example: $ labgrid-client -c config_remote.yaml inst identify --name "tm-inst-visa-rigol-psu_ch2" with "tm-inst-visa-rigol-psu_ch2" driver configured in config_remote.yaml (expected ps-rigol resource exported): targets: main: resources: RemotePlace: name: !template 'MyPlace' drivers: - PyVISADriver: name: driver-visa-rigol-psu_ch2 bindings: { pyvisa_resource : 'ps-rigol'} - TMInstrument: bindings: { inst : 'driver-visa-rigol-psu_ch2' } name: 'tm-inst-visa-rigol-psu_ch2' Signed-off-by: Martin Sabol <martin.sabol@seznam.cz>

Add convenient functionality for: - Rigol Technologies DP832, 3-channel laboratory power supply - Siglent Technologies SDM3065X-SC laboratory DMM - RND 320-KD3305P, 3-channel laboratory power supply - ITECH Electronics IT-M3632, power supply and regenerative DC load Signed-off-by: Martin Sabol <martin.sabol@seznam.cz>

@gastmaier

apply suggestion from @gastmaier: - use find_spec from importlib to check for module availability. - remove un-necessary try-catch block Co-authored-by: Jorge Marques <2892061+gastmaier@users.noreply.github.com> Signed-off-by: Martin Sabol <martin.sabol@seznam.cz>

- update pyvisadriver part - add: - tminstrument driver - tminstrumentpower driver - networkpyvisa resource - extend pyvisa resource usage Signed-off-by: Martin Sabol <martin.sabol@seznam.cz>

It shows how to use more then pne instrument. Here as example two USBTMC instrumnets, multimeter / power supply. Signed-off-by: Martin Sabol <martin.sabol@seznam.cz>

Sabolik · 2026-04-13T11:12:29Z

@threexc Did you find some time to test this?

I've been looking at it. I was able to do a basic test on my side with my SDG1032X and confirm it can communicate:
(venv) tgamblin@outpost:~/workspace/git/labgrid-power-up$ labgrid-client -c workbench/wb-client.yaml inst identify --name 'tm-inst-sdg1032x'
Selected role main and place workbench from configuration file
/usr/lib/python3/dist-packages/pyvisa_py/protocols/usbtmc.py:116: UserWarning: Unexpected MsgID format. Consider updating the device's firmware. See https://github.com/pyvisa/pyvisa-py/issues/20Expected message id was 2, got 46.
  warnings.warn(
Siglent Technologies,SDG1032X,SDG1XDFQ6R5627,1.01.01.33R
This is with the following exporter config for the device:
  wb-generator-1:
    cls: 'PyVISADevice'
    type: 'USB0'
    url: '0xF4EC::0x1103::SDG1XDFQ6R5627::0'
    backend: '@py'
and a client config like:
      - PyVISADriver:
          name: 'sdg1032x-driver'
          bindings:
            pyvisa_resource: 'wb-generator-1'
      - TMInstrument:
          name: 'tm-inst-sdg1032x'
          bindings:
            inst: 'sdg1032x-driver'
Seems reasonable enough to me. My only major issue with this PR is that there are examples in the commits but not really any updates to the docs? It would be good to have decent examples of the exporter and client configs, along with example commands to run (the ones in some of the commit messages that I've been pointed at are probably enough).

@Sabolik, can you add another commit to reflect that?

doc/configuration.rst: has been updated
examples/tminstrument: added example with two instruments, tested
labgrid-client usage example, I am unfortunatelly not sure where to put such example. There is generic labgrid-client CLI usage well docummented on Manual Pages.

Emantor requested changes Mar 4, 2026

View reviewed changes

Sabolik force-pushed the vzlu/pyvisa branch 3 times, most recently from 10cc6cf to fdda33e Compare March 5, 2026 14:46

threexc mentioned this pull request Mar 19, 2026

Agents not consistent with environment Python #1839

Open

gastmaier reviewed Mar 24, 2026

View reviewed changes

Sabolik force-pushed the vzlu/pyvisa branch from 194dd27 to c613238 Compare March 26, 2026 14:48

leinher and others added 10 commits March 30, 2026 14:11

driver/usbvideodriver: add support for Anivia W8 Webcam

a59de8b

Signed-off-by: Hermann Leinweber <hermann.leinweber@erweka.com>

driver: add pyVISA remote resource support

5835b2e

Introduce NetworkPyVISADevice for remote access to pyVISA resources. Use an agent wrapper to support both local and remote resource access. Signed-off-by: Martin Sabol <martin.sabol@seznam.cz>

examples: pyvisa driver does not support get_session method anymore

7805ca0

It has been replaced by visa_instrument.py agent. Signed-off-by: Martin Sabol <martin.sabol@seznam.cz>

driver: pyvisa: introduce query of iterables

250facf

Add a method to the tminstrument driver for querying iterables, such as lists of readings. Signed-off-by: Martin Sabol <martin.sabol@seznam.cz>

Sabolik force-pushed the vzlu/pyvisa branch 2 times, most recently from 1a4bb48 to 1d8be29 Compare March 30, 2026 12:38

Sabolik and others added 2 commits March 30, 2026 14:43

doc: extend configuration part.

e5b0db7

- update pyvisadriver part - add: - tminstrument driver - tminstrumentpower driver - networkpyvisa resource - extend pyvisa resource usage Signed-off-by: Martin Sabol <martin.sabol@seznam.cz>

Sabolik force-pushed the vzlu/pyvisa branch from 1d8be29 to e5b0db7 Compare March 30, 2026 12:45

example: add tminstrument driver usage example.

03ddc93

It shows how to use more then pne instrument. Here as example two USBTMC instrumnets, multimeter / power supply. Signed-off-by: Martin Sabol <martin.sabol@seznam.cz>

Sabolik closed this Apr 13, 2026

Sabolik reopened this Apr 13, 2026

Uh oh!

Conversation

Sabolik commented Mar 4, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

Emantor left a comment

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Sabolik commented Mar 5, 2026

Uh oh!

threexc commented Mar 10, 2026

Uh oh!

Sabolik commented Mar 10, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

Emantor commented Mar 19, 2026

Uh oh!

threexc commented Mar 19, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Sabolik commented Apr 13, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

5 participants

Sabolik commented Mar 4, 2026 •

edited

Loading

Sabolik commented Mar 10, 2026 •

edited

Loading

threexc commented Mar 19, 2026 •

edited

Loading

Sabolik commented Apr 13, 2026 •

edited

Loading