Re: [Linux-gpib-general] how to program wait_for_srq with linux-gpib in Python

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Hi Dave,

thank you very much for that short working example.

I will try that as soon as my system is setup properly again.
(Could take some time though :-(  )

As you are the second person with a working  *** wait( SRQ ) ***  example i think it should be a problem with my setup.

Just out of curiosity, is it just for your convenience that you use the 1<<12 and 1<<14 as a value for the mask parameter?

Will that be transferred via the binding/c-wrapping exactly like the hex values ( 0x800 / 0x1000 ) ?

Anyway, i will try both when my system is up again.

Thanks a lot for looking at this!

Joerg

> On 10. Sep 2017, at 21:11, dave penkler <dpe...@gm...> wrote:
> 
> Hi Joerg,
> I have tried this little program on a vanilla 4.0.3 with a BEIMING adaptor which behaves like an Agilent 82357a
> 
> Below is the code and the log running it once when pressing a function key and the other time without.
> Note that the wait function is on the board and not the device.
> Hope this helps.
> cheers,
> -Dave
> 
> $ cat srq.py 
> import sys
> sys.path.append('/usr/local/lib64/python2.7/site-packages')
> import gpib
> 
> board  = 2
> device = 1
> SRQI   = (1<<12)
> TIMO   = (1<<14)
> 
> # Shamelessly borrowed from cfo
> def query(handle, command, numbytes=100):
>         gpib.write(handle,command)
>         response = gpib.read(handle,numbytes)
>         response = response.rstrip("\r\n") 
>         return response
> 
> print gpib.version()          # Show package version
> t = gpib.dev(board,device)    # Open the HP9111A Graphics tablet
> gpib.clear(t)                 # Start out clean
> print query(t,"OI")           # Output ID
> gpib.write(t,"DF")            # Default mode
> gpib.write(t,"IM 7,128,0")    # Assert SRQ on special function key
> gpib.wait(board, TIMO | SRQI) # Wait for special function key
> sta = gpib.ibsta()            # Get status
> if (sta & TIMO) != 0:
>    print "Timed out"
> else:
>   print "SRQ asserted"
>   print query(t, "RS")        # Request special function key index
> gpib.close(t)
> $ python srq.py 
> 4.0.3
> 9111T
> SRQ asserted
> 1
> $ python srq.py 
> 4.0.3
> 9111T
> Timed out
> $
> 
> 
> On Mon, Sep 4, 2017 at 10:18 PM, J. Sommersberg <js...@gm... <mailto:js...@gm...>> wrote:
> Hello Wilhelm,
> 
> thank you for answering.
> 
> It doesn’t work for me ( i described it in my first post )
> 
> I will get an error about invalid arguments.
> 
> I can do it with the supplied ibtest tool.
> I found out that this tool is written in C.
> So it seems like my implementation of the Python-C interface is broken at this point.
> 
> I am digging deep into all docs of C and Python and try to understand how the wrapping is done in detail.
> 
> I tried to make a quick hack with gpinter.c which seems to be the place where the magic Python-C glueing is done.
> 
> I did some copy&paste with the declartion of gpib_wait function.
> 
> My copy looks like this
> 
> /* joerg 1.9.2017 try to use waitsrq                        */
>  
>  
>  
>  
> static char gpib_waitsrq__doc__[] =
> "waitsrq -- wait for the SRQ event (board)\n"
> "waitsrq(handle)";
> 
> static PyObject* gpib_waitsrq(PyObject *self, PyObject *args)
> {
>     int device;
>     int mask = SRQI;
>     int result;
>     
>     if (!PyArg_ParseTuple(args, "i:waitsrq", &device))
>         return NULL;
>     
>     Py_BEGIN_ALLOW_THREADS
>     sta = ibwait(device, mask);
>     Py_END_ALLOW_THREADS
>     
>     if(sta & ERR) {
>         _SetGpibError("waitsrq");
>         return NULL;
>     }
>     
>     return PyInt_FromLong(sta);
> }
> 
>  
>  
>  
> /* waitsrq joerg                                            */
> 
> ./configure
> make
> make install
> 
> i am getting no errors.
> 
> 
> But when i try to use the „new“ function:
> gpib.waitsrq(interface)
> 
> i am getting an error
> 
> AttributeError: 'module' object has no attribute 'waitsrq'
> 
> I admit, that would have been too easy :-)
> 
> 
> So i need to dig some more….
> 
> 
> Any help is highly appreciated!
> 
> Thanks
> 
> Joerg
> 
> 
> 
>> On 2. Sep 2017, at 16:03, Wilhelm Kusian <ku...@t-... <mailto:ku...@t-...>> wrote:
>> 
>> Hi Joerg,
>> 
>> I recognized that you are using Python to program your DMM. I do the same with a DMM Prema 6031 that also understands IEEE488.1 only.
>> 
>> In order to wait for the SRQ I'm using the following commands:
>> 
>> def measure():
>>     gpib.serial_poll(DMM)        # reset SRQ-Bit
>>     gpib.write(DMM,"MR")         # start measurement and display result (special for Prema 6031)
>>     gpib.wait(interface, 0x1000) # wait for SRQ-Bit
>>    x = gpib.read(DMM,13)        # readout measurement result (13 characters are special for Prema 6031)
>>    gpib.wait(interface, 0x100)  # wait for I/O-Operation complete
>>     return float(X)   
>> 
>> This function is called with
>> x = measure()
>> 
>> In my case this works perfect. Hope that this will help you.
>> 
>> Best regards
>> Wilhelm
>> 
>> 
>> 
>> Am 30.08.2017 um 19:43 schrieb ve...@mi... <mailto:ve...@mi...>:
>>> What gpib card are you using?
>>> 
>>> For waiting on SRQ, I usually do either this:
>>> 
>>> -------------------------------
>>>     ii = iblines(gpib,&clines);
>>>     if(ii & ERR) {
>>>         fprintf(stderr,"an error (%d) occurred in iblines.\n",iberr);
>>>     }
>>> 
>>>     if(clines & BusSRQ)
>>>         return 1;
>>> 
>>>     else
>>>         return 0;
>>> -------------------------------
>>> 
>>> 
>>> or this:
>>> 
>>> 
>>> -------------------------------
>>>         ss = 0;
>>>         adr[0] = dev;
>>>         adr[1] = NOADDR;
>>>         ReadStatusByte(gpib,adr[0],&ss);
>>>         fprintf(stderr,"ONE ADR: %d, Status: 0x%x\nibcnt: %d\n",
>>>                 adr[0],(int)ss,ibcnt);
>>> 
>>>         fprintf(stderr,"error variable: %d\nibsta: 0x%x\n",
>>>                 iberr,ibsta);
>>> 
>>>         if(iberr & 20) {
>>>             fprintf(stderr,"No SRQ requested\n");
>>>             return 0;
>>>         }
>>>         return (int)ss;
>>> -------------------------------
>>> 
>>> The second one didn't work with some cards, mainly the non-NI cards.
>>> 
>>> Vince.
>>> 
>>> 
>>> 
>>>> Hi,
>>>> 
>>>> i am trying to log data from an old DMM.
>>>> That device can only do IEEE488.1 standard.
>>>> 
>>>> I am able to do almost all functions.
>>>> 
>>>> I can send the ASCII strings to configure the device ( function, range ,
>>>> integration time, â€¦. ) with gpib.write(instrument,â€œCOMMANDâ€œ).
>>>> 
>>>> I can read the result of a measurement with gpib.read(instrument).
>>>> 
>>>> What i can not do ( at least on my linux-box ) is the programming to wait
>>>> for the SRQ ( service request ) event of the device.
>>>> 
>>>> I need it because i am using long integration times ( 20s, 40s, 80s ) and
>>>> i dont want to set the timeout variable to such a long time.
>>>> So i think the cleanest way to program this is the wait_for_srq() function
>>>> which is not available in linux-gpib.
>>>> 
>>>> On my winows notebook i have the pyvisa modul ( package? ) installed and i
>>>> can program it very nicely.
>>>> 
>>>> while TRUE:
>>>> 	instrument.wait_for_srq()
>>>> 	print (instrument.read())
>>>> 
>>>> It works perfectly.
>>>> 
>>>> I thought that the wait() function of linux-gpib should give a similar
>>>> result when used properly.
>>>> 
>>>> So i tried it in the Python shell:
>>>> 
>>>> gpib.wait(interface,0x1000)
>>>> gpib.GpibError: wait() failed: One or more arguments to the function call
>>>> were invalid.
>>>> 
>>>> gpib.wait(instrument,0x800)
>>>> ( this call will never return, i have to send CTRL-C )
>>>> 
>>>> I checked with the ibtest tool and it looks like the bit is set
>>>> 
>>>> get bus line status returns:
>>>> DAV off
>>>> NDAC on
>>>> NRFD off
>>>> IFC off
>>>> REN on
>>>> SRQ on
>>>> ATN on
>>>> EOI off
>>>> gpib status is:
>>>> ibsta = 0x1174  < SRQI CMPL REM CIC ATN LACS >
>>>> 
>>>> when i serial poll the instrument the SRQ bit gets cleared.
>>>> 
>>>> Am i having a very basic misunderstanding on how to implement this in
>>>> Python ( without Pyvisa )?
>>>> 
>>>> Or is it just a bug in the Python version of linux-gpib?
>>>> 
>>>> Any help is very much appreciated.
>>>> 
>>>> 
>>>> Best regards
>>>> 
>>>> Joerg------------------------------------------------------------------------------
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>>>> 
>> 
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> 
> 
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Re: [Linux-gpib-general] how to program wait_for_srq with linux-gpib in Python

Linux GPIB Driver package (source)

Re: [Linux-gpib-general] how to program wait_for_srq with linux-gpib in Python