python-ivi / python-vxi11

Provides a VXI-11 driver for controlling instruments over Ethernet

Python VXI-11 Readme

For more information and updates: http://alexforencich.com/wiki/en/python-vxi11/start

GitHub repository: https://github.com/python-ivi/python-vxi11

Google group: https://groups.google.com/d/forum/python-ivi

Introduction

Python VXI-11 provides a pure Python VXI-11 driver for controlling instruments over Ethernet.

Requirements

• Python 2 or Python 3

Installation

Extract and run

# python setup.py install

Usage examples

Connecting to Agilent MSO7104A via LXI:

import vxi11
instr =  vxi11.Instrument("192.168.1.104")
print(instr.ask("*IDN?"))
# returns 'AGILENT TECHNOLOGIES,MSO7104A,MY********,06.16.0001'

Connecting to Agilent E3649A on GPIB address 5 via HP 2050A GPIB bridge:

import vxi11
instr = vxi11.Instrument("192.168.1.105", "gpib,5")
print(instr.ask("*IDN?"))
# returns 'Agilent Technologies,E3649A,0,1.4-5.0-1.0'

Connecting to Agilent MSO-X 3014A via USBTMC via Agilent E5810 GPIB bridge:

import vxi11
instr = vxi11.Instrument("192.168.1.201", "usb0[2391::6056::MY********::0]")
print(instr.ask("*IDN?"))
# returns 'AGILENT TECHNOLOGIES,MSO-X 3014A,MY********,02.35.2013061800'

It is also possible to connect with VISA resource strings like so:

import vxi11
instr =  vxi11.Instrument("TCPIP::192.168.1.104::INSTR")
print(instr.ask("*IDN?"))
# returns 'AGILENT TECHNOLOGIES,MSO7104A,MY********,06.16.0001'

and:

import vxi11
instr = vxi11.Instrument("TCPIP::192.168.1.105::gpib,5::INSTR")
print(instr.ask("*IDN?"))
# returns 'Agilent Technologies,E3649A,0,1.4-5.0-1.0'

and:

import vxi11
instr = vxi11.Instrument("TCPIP::192.168.1.201::usb0[2391::6056::MY********::0]::INSTR")
print(instr.ask("*IDN?"))
# returns 'AGILENT TECHNOLOGIES,MSO-X 3014A,MY********,02.35.2013061800'

python-vxi11's Issues

bytes -> bytearrays in read procedures

I had to transmit a lot of 128MB waveforms from my scope to the computer, which was extremely slow. After changing all the "bytes +=" parts in the read procedures to "bytearray.append", I was able to speed the process up by a factor of 10.

So I suggest applying these changes here too.

Setting socket Timeout on Instrument Class

Reading through the code, seems as though doing:

instrument_handle = "TCPIP::169.254.14.7::INSTR"
c = vxi11.Instrument(instrument_handle)
c.timeout = MY_TIMEOUT_IN_SECONDS

would work appropriately for setting the socket timeout duration.
Unfortunately, it seems the socket timeout duration is the same regardless of me setting this value.
Any thoughts on this?

Please implement a configurable timeout

Hello,

I have successfully used the python-vxi11 on a rigol MSO1104z over TCP.
See
https://github.com/x8-999-github/cw-projects-experiments/blob/master/visa/Scope_arm_and_capture.ipynb and

https://github.com/x8-999-github/cw-projects-experiments/blob/master/visa/VXI_MSO1104z.ipynb

The main problem was a timeout I was getting when connecting.
Is it possible to make the socket timeout configurable(I hardcoed it here)?

#diff --git a/vxi11/rpc.py b/vxi11/rpc.py
#index 9d889a6..c744f8c 100644
#--- a/vxi11/rpc.py
#+++ b/vxi11/rpc.py
#@@ -257,6 +257,7 @@ class RawTCPClient(Client):
# 
#     def connect(self):
#         self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
#+       self.sock.settimeout(2.0)
#         self.sock.connect((self.host, self.port))
# 
#     def close(self):

Vxi11Exception: 15 IOTimeout with Keysight E5810B connected devices only

When my instruments are connected directly to my PC, either by USB or by GPIB-USB converter, I can communicate with them without issue. However, when I connect to them through the Keysight E5810B bridge via GPIB, I get the IO timeout in the subject line.

The IO timeout occurs for roughly 75% of all commands -- at times, the very same commands are successful.

I can see that the E5810B gateway has the LAN and GPIB LEDs flash green during communication, indicating that it is receiving the command. But, alas, the timeout error usually plagues communication.

Is there a particular set of configuration commands that need to be sent for using the gateway?

Steps to debug:

• increase timeout
• Preset E5810B gateway and reconfigure
• secured HW connections
• verified issue does not occur with direct connection to PC. only connection to gateway

Here are specific details of the setup:

• Keysight E5810B fresh out of the box, configured with a static IP on a corporate LAN FW B.01.07 (latest)
• Keysight N7752A Power Meter + VOA connected to the E5810B via GPIB (also used Tektronix TDS744, Agilent 86142 OSA, etc.)
• Windows 10 host OS
• using VXI11 version 0.9

Code:

import vxi11
inst = vxi11.Instrument("138.120.217.76", "gpib0,5") 
inst.ask("*IDN?")       # Fails with vxi11Exception
inst.timeout = 10000
inst.ask("*IDN?")      # Fails with vxi11Exception

Rigol LXI - via NAT

Hello,

I have my Rigol instrument connected to router in local network with forwarding port 5555 to external address (f.eg. 8000).
Can I use contructior of vxi11.Instrument class with host:port?

vxi11.Instrument("192.168.1.104:8000")

Becase I have 5 Rigols I need to forward each of them to separate port (8000, 8001,...)

F

advice for vxi11-gpib bridge

not to request a product endorsement, but could give some links products that will allow me to control GPIB instruments with python-vxi11?

i have been goggling and i am confused as to what does what. do you have experience with a specifc product, that is still purchasable?

Problems connecting to GW Instek MFG-2230-M

I think this is an implementation issue at GWI, but wondered if anyone had any ideas or previous experience? I suspect this is all due to me not understanding the difference between VISA, VXI, LXI etc., but I have been working happily with PyMeasure in a way that seems to work OK, until I hit this problem.

I have several instruments that all seem to work quite happily, but not this one (GW Instek MFG-2230-M). I think it will only accept VISA connections, so a connection string something like:

“TCPIP :: 172.16.28.144 :: 1026 :: SOCKET”

.. which is rejected by the vxi11 library as a malformed string, and presumably it would need to parse the socket number as well, rather than performing the vxi protocol (or whatever it is) to establish a socket.

If I try a connection string like: “TCPIP :: 172.16.28.144 :: INSTR”, this is accepted by the vx11 library, but I just get a "connection refused" error when I try to send a message.

Timout when reading more than max_recv_size bytes

When trying to read raw binary data with more than 16*1024=16384 bytes (this is the value of max_recv_size), I get I/O TIMEOUT Errors.

I have seen in the source code that data is received in packages up to max_recv_size bytes and then joined.

I tried to manually set smaller or larger values for max_recv_size without success.
However, I found out, that in fact there are only a few bytes missing, causing the last client.device_read(...) to produce a timeout.
For example if I set max_recv_size=4096 and try to read 32000 bytes I can receive 7 packages à 4096 bytes (thats 28672 in total) but the last read call raises a timeout exception because it can't read all of the expected missing 3328 bytes (but probably some or even most of them).

It is just an idea, but maybee there are bytes lost in the timewindow between the calls to client.device_read(...) where you append data to the previously read?

Any thoughts on that?

close() hanging if a Ctrl+C presseed ie. KeyboardInterrupt was raised

The Instrument.close() method hanging (or throws a timeout exception) if ctrl+c was pressed during a read operation.
Some instrument commands consume time (eg.: saving/fetching screenshot of the oscilloscope). If I press Ctrl+C during an ask() or read(), the close()method cannot finish properly: it throws timeout error after the timeout time has been elapsed, which timeout must be big in some cases (because of the time consuming commands.)

create_intr_chan error

line 443, you use pack_device_docmd_params, the correct call is be unpack_device_remote_func_parms.

Support list_devices()

I have some proprietary (closed source) super slow C library for working with vxi11 and that one provides a function that returns all vxi11 devices at the network (and that's fast). This is the only function I miss in this python library.

Is there any chance to provide a search function in this library as well?

Interface timeout / hangs on *RST for Rigol DP832

Trying this simple sequence of commands sometimes hangs the LAN interface of the Rigol DP832(A) with firmware version 00.01.14.00.03 and resets the connection:

Python 2.7.6 (default, Nov 23 2017, 15:49:48) 
[GCC 4.8.4] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import vxi11
>>> inst = vxi11.Instrument("192.168.1.15")
>>> inst.ask("*IDN?")
u'RIGOL TECHNOLOGIES,DP832,DP8C194205678,00.01.14'
>>> inst.ask("*RST")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.7/dist-packages/vxi11/vxi11.py", line 743, in ask
    return self.read(num, encoding)
  File "/usr/lib/python2.7/dist-packages/vxi11/vxi11.py", line 731, in read
    return self.read_raw(num).decode(encoding).rstrip('\r\n')
  File "/usr/lib/python2.7/dist-packages/vxi11/vxi11.py", line 701, in read_raw
    raise Vxi11Exception(error, 'read')
vxi11.vxi11.Vxi11Exception: 15: IO timeout [read]
>>>

$ cat /usr/lib/python2.7/dist-packages/vxi11/version.py
__version__ = '0.9'

Sometimes the connection seems to be only half closed so that further commands or a reconnection to the device fails until the DP832 is power-cycled. In this state the web interface does not work as well.

Doing the same directly via telnet 192.168.1.15 5555 does not cause any problems.

FINDLSTN via E5810a

How do I issue the command FINDLSTN to the ethernet<->gpib converter (Agilent E5810a) to list all active listeners?

I've read the source code and it isn't apparent how to accomplish this.

An attempt produces this:

import vxi11
i=vxi11.Instrument("*************","gpib0")
i.ask("FINDLSTN")
Traceback (most recent call last):
File "", line 1, in
File "/usr/lib/python3.5/site-packages/vxi11/vxi11.py", line 664, in ask
return self.read(num, encoding)
File "/usr/lib/python3.5/site-packages/vxi11/vxi11.py", line 652, in read
return self.read_raw(num).decode(encoding).rstrip('\r\n')
File "/usr/lib/python3.5/site-packages/vxi11/vxi11.py", line 622, in read_raw
raise Vxi11Exception(error, 'read')
vxi11.vxi11.Vxi11Exception: 17: IO error [read]

or

import vxi11
i=vxi11.Instrument("*************") # No gpib0 (in hopes to enumerate com port as well
Traceback (most recent call last):
File "", line 1, in
File "/usr/lib/python3.5/site-packages/vxi11/vxi11.py", line 663, in ask
self.write(message, encoding)
File "/usr/lib/python3.5/site-packages/vxi11/vxi11.py", line 648, in write
self.write_raw(str(message).encode(encoding))
File "/usr/lib/python3.5/site-packages/vxi11/vxi11.py", line 560, in write_raw
self.open()
File "/usr/lib/python3.5/site-packages/vxi11/vxi11.py", line 530, in open
raise Vxi11Exception(error, 'open')
vxi11.vxi11.Vxi11Exception: 3: Device not accessible [open]

Specifying term_char is broken

I get this traceback when specifying term_char on python 3.8:

File "/usr/lib/python3.8/site-packages/vxi11/vxi11.py", line 727, in write
self.write_raw(str(message).encode(encoding))
File "/usr/lib/python3.8/site-packages/vxi11/vxi11.py", line 640, in write_raw
data += term_char
TypeError: can't concat int to bytes

It seems this can be fixed by changing line 639 from:
term_char = str(self.term_char).encode('utf-8')[0]
to:
term_char = str(self.term_char).encode('utf-8')[:1]

ImportError: No module named vxi11

Hell guys,
I tried to install the vxi11 python lbrary in Ubuntu 16.04 using the next command:

sudo python setup.py install

I get the next log:

_running install
running bdist_egg
running egg_info
writing python_vxi11.egg-info/PKG-INFO
writing top-level names to python_vxi11.egg-info/top_level.txt
writing dependency_links to python_vxi11.egg-info/dependency_links.txt
writing entry points to python_vxi11.egg-info/entry_points.txt
reading manifest file 'python_vxi11.egg-info/SOURCES.txt'
reading manifest template 'MANIFEST.in'
writing manifest file 'python_vxi11.egg-info/SOURCES.txt'
installing library code to build/bdist.linux-x86_64/egg
running install_lib
running build_py
creating build/bdist.linux-x86_64/egg
creating build/bdist.linux-x86_64/egg/vxi11
copying build/lib.linux-x86_64-2.7/vxi11/cli.py -> build/bdist.linux-x86_64/egg/vxi11
copying build/lib.linux-x86_64-2.7/vxi11/vxi11.py -> build/bdist.linux-x86_64/egg/vxi11
copying build/lib.linux-x86_64-2.7/vxi11/version.py -> build/bdist.linux-x86_64/egg/vxi11
copying build/lib.linux-x86_64-2.7/vxi11/init.py -> build/bdist.linux-x86_64/egg/vxi11
copying build/lib.linux-x86_64-2.7/vxi11/rpc.py -> build/bdist.linux-x86_64/egg/vxi11
byte-compiling build/bdist.linux-x86_64/egg/vxi11/cli.py to cli.pyc
byte-compiling build/bdist.linux-x86_64/egg/vxi11/vxi11.py to vxi11.pyc
byte-compiling build/bdist.linux-x86_64/egg/vxi11/version.py to version.pyc
byte-compiling build/bdist.linux-x86_64/egg/vxi11/init.py to init.pyc
byte-compiling build/bdist.linux-x86_64/egg/vxi11/rpc.py to rpc.pyc
creating build/bdist.linux-x86_64/egg/EGG-INFO
copying python_vxi11.egg-info/PKG-INFO -> build/bdist.linux-x86_64/egg/EGG-INFO
copying python_vxi11.egg-info/SOURCES.txt -> build/bdist.linux-x86_64/egg/EGG-INFO
copying python_vxi11.egg-info/dependency_links.txt -> build/bdist.linux-x86_64/egg/EGG-INFO
copying python_vxi11.egg-info/entry_points.txt -> build/bdist.linux-x86_64/egg/EGG-INFO
copying python_vxi11.egg-info/top_level.txt -> build/bdist.linux-x86_64/egg/EGG-INFO
zip_safe flag not set; analyzing archive contents...
creating 'dist/python_vxi11-0.9-py2.7.egg' and adding 'build/bdist.linux-x86_64/egg' to it
removing 'build/bdist.linux-x86_64/egg' (and everything under it)
Processing python_vxi11-0.9-py2.7.egg
Removing /usr/local/lib/python2.7/dist-packages/python_vxi11-0.9-py2.7.egg
Copying python_vxi11-0.9-py2.7.egg to /usr/local/lib/python2.7/dist-packages
python-vxi11 0.9 is already the active version in easy-install.pth
Installing vxi11-cli script to /usr/local/bin

Installed /usr/local/lib/python2.7/dist-packages/python_vxi11-0.9-py2.7.egg
Processing dependencies for python-vxi11==0.9
Finished processing dependencies for python-vxi11==0.9_

as you can see there is no errors in the installation, when I tried to use in my python script:

import vxi11

get me the next error:

import vxi11
ImportError: No module named vxi11

any idea what I did wrong?

SALUDOS!!!!!

Instrument.write_raw() and term_char

I'm using Python 3.5 on Ubuntu.

I modified this routine to show what I think it should be. Before it was flags = OP_FLAG_TERMCHAR_SET if a terminating char exists but was immediately followed by flags = 0.

But I'm also confused by the behavior if term_char is set. It looks like the intent is the convert it to an integer than append to data. I've been passing bytes objects to this routine. This will fail when it attempts data += term_char. Also you cannot specify term_char as a single element bytes literal such as b'\r'.

If the encoding is assumed to be 'UTF-8' anyway shouldn't this line simply be ord(term_char)?

I might also change the if self.term_char is not None to if self.term_char for readability/simplicity.

    def write_raw(self, data):
        "Write binary data to instrument"
        if self.link is None:
            self.open()

        # TODO: Test
        flags = 0

        if self.term_char is not None:
            flags |= OP_FLAG_TERMCHAR_SET
            term_char = str(self.term_char).encode('utf-8')[0]
            data += term_char

        # Was this: flags = 0

        num = len(data)

Timeout when sending a *IDN? command to a Siglent SDS2000 scope

I'm trying to get python-vxi11 working with all of my test equipment, and most of my instruments work great with it except for my Siglent SDS2000 scope. When sending the *IDN? command the ask command hangs, and then times out. I've included the wireshark file if it helps.

Tracing through the code, it seems to attempt to open a second connection to the instrument, and hangs up there.

This is what gets returned after a while:

File "/home/srodgers/projects/python/PycharmProjects/dp832/instrument.py", line 60, in identify
return self.s.ask("*IDN?")
File "/usr/local/lib/python3.4/dist-packages/python_vxi11-0.8-py3.4.egg/vxi11/vxi11.py", line 717, in ask
File "/usr/local/lib/python3.4/dist-packages/python_vxi11-0.8-py3.4.egg/vxi11/vxi11.py", line 702, in write
File "/usr/local/lib/python3.4/dist-packages/python_vxi11-0.8-py3.4.egg/vxi11/vxi11.py", line 610, in write_raw
File "/usr/local/lib/python3.4/dist-packages/python_vxi11-0.8-py3.4.egg/vxi11/vxi11.py", line 580, in open
File "/usr/local/lib/python3.4/dist-packages/python_vxi11-0.8-py3.4.egg/vxi11/vxi11.py", line 493, in init
File "/usr/local/lib/python3.4/dist-packages/python_vxi11-0.8-py3.4.egg/vxi11/rpc.py", line 522, in init
File "/usr/local/lib/python3.4/dist-packages/python_vxi11-0.8-py3.4.egg/vxi11/rpc.py", line 257, in init
File "/usr/local/lib/python3.4/dist-packages/python_vxi11-0.8-py3.4.egg/vxi11/rpc.py", line 261, in connect
TimeoutError: [Errno 110] Connection timed out

wireshark.zip

New release for PyPI?

Hi Alex
Do you have any plans to make a new release of python-vxi11? The latest version in PyPI is 0.9. Since then there have been various improvements (performance and list_resources). It would be nice if these were available when installing with Pip.

How to use your tcp server

Hi,
I'm not able to work with your TCPServer. Would you have an example of how you use it?

Problem with max_recv_size

There seems to be a problem with the max_recv_size value that is returned by the CoreClient.create_link() method. The code that's calling it is in vxi11/vxi11.py.

In particular, the line that I believe is causing the issues is this:
error, link, abort_port, max_recv_size = self.client.create_link(self.client_id, 0, self.lock_timeout, self.name.encode("utf-8"))

The problem is the following:

I'm connecting to an Agilent DSO 9000 series via Ethernet. The max_recv_size returned is 4294967295. However, after trying to read something with this default setting I get an error:

import vxi11
instr = vxi11.Instrument("192.168.1.104")
print(instr.ask("*IDN?"))
Traceback (most recent call last):
File "", line 1, in
File "/usr/local/lib/python2.7/dist-packages/python_vxi11-0.5-py2.7.egg/vxi11/vxi11.py", line 418, in ask
return self.read(num, encoding)
File "/usr/local/lib/python2.7/dist-packages/python_vxi11-0.5-py2.7.egg/vxi11/vxi11.py", line 413, in read
return self.read_raw(num).decode(encoding).rstrip('\r\n')
File "/usr/local/lib/python2.7/dist-packages/python_vxi11-0.5-py2.7.egg/vxi11/vxi11.py", line 383, in read_raw
raise Vxi11Error("error reading data: %d" % error)
vxi11.vxi11.Vxi11Error: error reading data: 5

By using a manual receive size it works fine:

instr = vxi11.Instrument( ... hidden)
instr.write("*IDN?")
print instr.read(10000)
Agilent Technologies,DSO9054H,MY53060106,04.60.0005

I suspect that the returned max_recv_size is invalid, so I'm not sure how it would be best to fix this. Also I'm unsure if this is a problem of the create_link method or of the Agilent oscilloscope, since with a Lecroy oscilloscope this seems to work fine. Nevertheless it is annoying and it took me a while to realize what was the issue since it was not clear from the error message.

Maybe a fix would be to restrict the max_recv_size to something like 10^8 or 10^9 after the self.client.create_link call.

Keysight E5810B slows down after 10 connections

Each time a new TCP/IP connection is established with the Keysight E5810B, it internally spawns a process that takes 50-100% of a core's CPU power. It's possible that it's internally polling aggressively. When creating multiple Instrument objects, each with its own connection, at about 10 instruments the box slows down significantly as the CPU is at saturation.

An easy workaround would be to share the client connection between all Instruments and the InterfaceDevice.

I'd be happy to put up a PR that accepts an optional client input in the initializer; however, I'm not sure if this is the approach you would prefer. An alternative approach would be a connection pool keyed on the IP address of the host; it could then grab an existing connection rather than create a new one.

Tx/ Rx annotations

This is not really an issue but could not see anyplace to request a feature as below. So added it here.

So for the the ask function and write function using IDN as an example, would the output be able to show.
Tx> *IDN
Rx< device ID

Currently the command requested is not shown on the output, so if there was a complementary write or ask function that printed what command was sent that would be useful in a log.
Also the TX> and RX < with the <> brackets can be useful to show what was transmitted and what was received.

Obviously this functionality can be achieved, by printing the command and then sending it via ask or write, but if we can have a new combined function it will make a testers role much efficient in just writing single line instead of 2.

Hang sending large payloads to Keysight scopes

On Mac OS X, sending data larger than ~128K to a Keysight scope results in a timeout in recvfrag. This is caused by a bug in sendfrag where the code should have used sock.sendall instead of sock.send:

def sendfrag(sock, last, frag):
    x = len(frag)
    if last: x = x | 0x80000000
    header = struct.pack(">I", x)
    sock.sendall(header + frag)

USE PyVISA

This library is abandonware and broken on modern versions of Python.

Use PyVISA (https://pyvisa.readthedocs.io/en/1.8/names.html). It supports VXI11.

timeout for connexion

Hello!
I recently upgraded my version of vix11.py 0.8.1 => 0.9 and I no longer find my "instrument_timeout" and "connection_timeout" parameters during initialization:

instr=vxi11.Instrument(LecroyIP) 
instr.__init__(LecroyIP, instrument_timeout=5, connection_timeout=7)
#v0.8.1

I found "instrument_timeout" with:

instr=vxi11.Instrument(LecroyIP) 
instr.timeout=5 (s)

But I struggle a bit to find the "connection_timeout" that I used when my LECROY oscilloscopes are turned off or disconnected from the network.
I think it's not much but I just spent two mornings there lol
Have a nice day and thank you for your answers.
Guillaume

Request to support SRQ

I see that python-vxi11 has some code that says "SRQ", but it's not clear to me how to use it.

According to this thread I suspect that the functionality might not yet be properly implemented.

My use case is that our instrument sends an "SRQ" event when the data is ready, then I guess that I need to read the status byte and run a function that reads the data out.

I think that this library supports SRQ, but it does it via some C++.

Write/Ask commands need newline added to end

Fantastic library!
Following the provided examples I was unable to get any response from my machine, however adding a \n to the end of each command put things in gear. I'm running Linux (Debian 7) and wondered if it was a platform thing? In vxi11.py I inserted the following line:

message += '\n'

after line 396 and now everything runs as intended.

Rigol DM3068 workaround Device locked by another link [write]

Hello,

Got a new DM3068 yesterday and have been trying to connect to it without success. After a lot of searching it turns out that it require the lock_timeout to be set to 0 ( http://optics.eee.nottingham.ac.uk/vxi11/ ). Could be a useful example, it would have saved me hours.

import vxi11
instr = vxi11.Instrument("192.168.1.171")
print(instr.ask("*IDN?"))
Traceback (most recent call last):
File "", line 1, in
File "vxi11/vxi11.py", line 495, in ask
File "vxi11/vxi11.py", line 480, in write
File "vxi11/vxi11.py", line 423, in write_raw
vxi11.vxi11.Vxi11Exception: 11: Device locked by another link [write]
Error in sys.excepthook:
Traceback (most recent call last):
File "/usr/lib/python2.7/dist-packages/apport_python_hook.py", line 67, in apport_excepthook
binary = os.path.realpath(os.path.join(os.getcwd(), sys.argv[0]))
OSError: [Errno 2] No such file or directory

Original exception was:
Traceback (most recent call last):
File "", line 1, in
File "vxi11/vxi11.py", line 495, in ask
File "vxi11/vxi11.py", line 480, in write
File "vxi11/vxi11.py", line 423, in write_raw
vxi11.vxi11.Vxi11Exception: 11: Device locked by another link [write]

instr.lock_timeout = 0
print(instr.ask("IDN?"))
Rigol Technologies,DM3068,DM3O********,01.01.00.01.08.00

bytes/str problem with LeCroy scope

Hi I am trying to use the vxi11 interface to retrieve data from a Lecroy scope, unfortunately I am running into a bytes/string problem

In [2]: vxi11.version.__version__
Out[2]: '0.9'

In [3]: i=vxi11.Instrument("129.20.84.103")

In [4]: i.ask("*IDN?")
Out[4]: '*IDN LECROY,HDO4054A,THZSCOPE,8.5.1'

In [5]: i.ask_raw("C1:WF? DESC")
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-5-b118bed726b3> in <module>()
----> 1 i.ask_raw("C1:WF? DESC")

/home/marco/.local/lib/python3.7/site-packages/vxi11/vxi11.py in ask_raw(self, data, num)
    714     def ask_raw(self, data, num=-1):
    715         "Write then read binary data"
--> 716         self.write_raw(data)
    717         return self.read_raw(num)
    718 

/home/marco/.local/lib/python3.7/site-packages/vxi11/vxi11.py in write_raw(self, data)
    657                 self._lock_timeout_ms,
    658                 flags,
--> 659                 block
    660             )
    661 

/home/marco/.local/lib/python3.7/site-packages/vxi11/vxi11.py in device_write(self, link, timeout, lock_timeout, flags, data)
    409         return self.make_call(DEVICE_WRITE, params,
    410                 self.packer.pack_device_write_parms,
--> 411                 self.unpacker.unpack_device_write_resp)
    412 
    413     def device_read(self, link, request_size, timeout, lock_timeout, flags, term_char):

/home/marco/.local/lib/python3.7/site-packages/vxi11/rpc.py in make_call(self, proc, args, pack_func, unpack_func)
    175         self.start_call(proc)
    176         if pack_func:
--> 177             pack_func(args)
    178         self.do_call()
    179         if unpack_func:

/home/marco/.local/lib/python3.7/site-packages/vxi11/vxi11.py in pack_device_write_parms(self, params)
    201         self.pack_uint(lock_timeout)
    202         self.pack_int(flags)
--> 203         self.pack_opaque(data)
    204 
    205     def pack_device_read_parms(self, params):

/usr/lib/python3.7/xdrlib.py in pack_string(self, s)
    106         n = len(s)
    107         self.pack_uint(n)
--> 108         self.pack_fstring(n, s)
    109 
    110     pack_opaque = pack_string

/usr/lib/python3.7/xdrlib.py in pack_fstring(self, n, s)
     98         data = s[:n]
     99         n = ((n+3)//4)*4
--> 100         data = data + (n - len(data)) * b'\0'
    101         self.__buf.write(data)
    102 

TypeError: can only concatenate str (not "bytes") to str

Thanks a lot,
marco

Benchmarks?

Hi,

I'm trying to pull waveform data off a R&S RTO 1014 via gigabit ethernet. At the moment, it is receiving data rather slowly (10Mbit), whereas if I connect an agilent scope with USB and usbtmc, I can push close to the limit of 480MBit (I estimate something like 350MBit). Unfortunately this R&S one doesn't have USB, so I am stuck with ethernet.

Are there any benchmarks on what sort of data rate I can expect using python-vxi11? For me right now, 15MB of waveform data takes about 6 seconds on a point-to-point gigabit ethernet connection (no router or switches in between) which is far too slow. I have checked and the interface is definitely running at 1000MBit.

I'm running Ubuntu 15.04 x64 on a Core i3 box, using the intel gigabit adapter on the motherboard.

ask_for_values

the pyvisa project used to have a function called ask_for_values , which believe has recently been renamed and re-written to query_values. essentially it was an ask, with delimiter splitting and casting, that was ideal for reading arrays.

in either case, this function is very useful, and was wondering if a similar thing could implemented in python-vxi11 or python-ivi (which ever is more appropriate). id be happy to do this

Invalid resource string

inst = vix11.Instrument("TCPIP:AAA99999-99999::INST0::INSTR")

why isn't this resource string accepted?

I'm trying to interact with a rohde-schwarz machine VXI-11 protocol format for addressing the devices in the machine is as follows:

"""
"TCPIP[board]::host address[::LAN device name][::INSTR]"

The LAN device name for sub-instrument n equals inst. Example: inst0 for sub-instrument 1. VXI-11 is a protocol that has been specifically developed for test and measurement instruments. """

Maybe the parse_visa_resource_string function needs some adjustments.

Regards,
Tyron

TCP Retransmissions happens in Linux connecting to older VXI-11 devices

I don't think it is really an issue, but I think it will make the application better than before.
I was working with an old device (I think it was created around nineties) that has an VXI-11 TCP server on it. I was trying to communicate with this device using both a Linux(Ubuntu 14,04) and a Windows machine. In the Windows machine, the communication was successful but on the Linux side it was not. In the Linux client, there was a lot of re-transmission and the calls started to become even more delayed because the way Linux deal with TCP protocol. I figured out it using Wireshark and analyzing the packets. After a while breaking my head on it, I figured out a solution.
In Linux we have a TCP feature called TCP_QUICKACK that is used to send out acknowledgements as early as possible than delayed under some protocol level exchanging, and it's not stable/permanent, subsequent TCP transactions. This feature was causing a lot of double ACK in the TCP communication because the device I was using can not deal with this quick ack packets. What I did to temporally fix the problem was disabling the socket TCP_QUICKACK in the socket properties in my application, but I think it would be more elegant and correct if we could add this option in the python-vxi11 library. I am running out of time so I forked the project and I will make a commit with this new option as soon as I get some time. If you guys have some better ideas than mine, I would be very grateful to listen from you. Thank you a lot.

Following is what I did to make my application work without changing anything on the python-vxi11 library. It is important to say that TCP_QUICKACK is restarted every socket send and recv command, so it has to be changed every time we send a command:

#!/usr/bin/python

import socket
import vxi11

def generateSocketSendAllWithoutTcpQuickAck(oldSocketSendAll, *args, **kwargs):
    def newSocketSendAll(*args, **kwargs):
        args[0].setsockopt(socket.IPPROTO_TCP, socket.TCP_QUICKACK, 0)
        oldSocketSendAll(*args, **kwargs)
    return newSocketSendAll

socket.socket.sendall = generateSocketSendAllWithoutTcpQuickAck(socket.socket.sendall)

oldDevice = vxi11.Instrument("192.168.170.33")

oldDevice.open()

answer = oldDevice.ask("*IDN?\n\r")

print "Version of Device: " + answer

oldDevice.close()

Use waitlock flag in lock()

lock() does not wait the lock timeout before failing. The waitlock flag (bit 0) is not being set. Is there a reason why this flag would never be set? If there is, perhaps add a default wait = False argument?

    def lock(self):
        "Send lock command"
        if self.link is None:
            self.open()

        # flags = 0

        # TODO: Added waitlock flag.
        flags = 1 

        error = self.client.device_lock(self.link,
                                        flags,
                                        self._lock_timeout_ms)

        if error:
            raise Vxi11Exception(error, 'lock')