2013/8/12 Marcos Anzorena <anzoren...@gmail.com>:
> Hello everyone:
>
> I wanted to share the code i wrote to communicate with a tektronix
> scope MSO2024. I used [0] and [1] as reference. I'm using PyUSB,
> libusb 1.0 and Fedora 16
>
> I wrote to main functions. One for opening the scope:
>
> def tekopen(idV=0x0699,idP=0x03A4):
> dev=usbc.find(idVendor=idV,idProduct=idP)
> if dev is None:
> raise ValueError('No se encontro el osciloscopio')
> if dev.is_kernel_driver_active(0):
> dev.detach_kernel_driver(0)
> dev.set_configuration()
> usbt.claim_interface(dev,0)
> return dev
>
> idV and idP can be obtained connecting the scope and then using "lsusb"
>
> The second function is for sending commands or queries to the scope:
>
> def tekcq(dev,comd,oendp=0x01,iendp=0x82):
> n=1
> ncomp=n^0xFF
> mlen=len(comd)
> fiveb=np.divide(mlen,256)
> fourb=np.mod(mlen,256)
> abytes=''
> if np.mod(mlen,4)!=0:
> nabytes=4-np.mod(mlen+12,4)
> for x in range(0,nabytes):
> abytes+=struct.pack('1B',0)
> header=struct.pack('12B',1,n,ncomp,0,fourb,fiveb,0,0,1,0,0,0)
> msg=header+comd+abytes
> if comd[-1]!='?':
> dev.write(oendp,msg,0,100)
> else:
> n=2
> ncomp=n^0xFF
> inr=struct.pack('12B',2,n,ncomp,0,0,1,0,0,0,0,0,0)
> dev.write(oendp,msg,0,100)
> dev.write(oendp,inr,0,100)
> if comd!=':curv?':
> res=dev.read(iendp,256,0,1000)[12:]
> res=res.tostring()
> return res
> else:
> res=dev.read(iendp,512,0,1000)
> fend=res[8]
> res=res[12:]
> data=np.array(res,dtype=np.uint8)
> while fend!=1:
> n+=1
> ncomp=n^0xFF
> inr=struct.pack('12B',2,n,ncomp,0,0,1,0,0,0,0,0,0)
> dev.write(oendp,inr,0,100)
> res=dev.read(iendp,512,0,1000)
> fend=res[8]
> res=res[12:]
> data=np.hstack((data,res))
> return data
>
> If we want to send a command to scope we use:
>
> tekcq(tek,':head off')
>
> If we want to send a query:
>
> a=tekcq(tek,':hor:sca?')
>
> One special case is when we want to query waveform data from the
> scope, in that case we use:
>
> data=tekcq(tek,':curv?')
>
> Hope is helpful for someone.
>
> [0] http://comments.gmane.org/gmane.comp.python.pyusb.user/477
>
> [1] http://www1.tek.com/forum/viewtopic.php?f=5&t=4389
>
>
This is something that better fits in an wiki. After I received a
sourceforge email notifying me that they were shutdown trac, I decided
to migrate everything but main page and downloads to github, but I had
no time, and eventually I think SF aborted this idea. I think I will
enable the github wiki for PyUSB, so people like you can put their
contributions there.
--
Best Regards,
Wander Lairson Costa
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