| Products > Test Equipment |
| Keithley 2015 measurements with computer display? |
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| Performa01:
As no one has mentioned it so far: AFAIK only the Keithley 2015P can perform spectrum analysis. The 2015 (without P) only does THD measurements. |
| 3roomlab:
--- Quote from: JSE009 on October 03, 2015, 06:48:19 pm ---I have a 2015 for a couple of weeks now and received my 2nd one today :-+ I played around with trying to communicate via RS232 by using a software program Putty and a USB/Serial adaptor. Until now I can not get the Keithley 2015 to response :o I also would like to get the data into Excell but do not now how to start :-// --- End quote --- i think i have just overcome most of the problems with my unit. (short of cleaning the innards) i use WinXP SP 3 --> Python 2.7 (pyserial 2.7) --> FTDI USB RS232 --> keithley 2015 THD i think many ppl use PROLIFIC RS232, and this was the cause of many problems. but after opening up the FTDI, it is not much of a tiptop gear either in terms of construction, its all made in china . the expensive bit is the genuine chip are you still having problems? i OTOH could not get NI VISA to work in python :( see here for python code, *xls logging (post #19) https://www.eevblog.com/forum/projects/is-this-a-real-ns-lm399-%28from-polida-ebay%29/msg769388/#msg769388 |
| 3roomlab:
--- Quote from: G0HZU on October 03, 2015, 07:41:07 pm ---I'm not a programmer by profession but I wrote my own Windows app for my little Win7 netbook a couple of years ago and it controls the Keithley 2015 remotely and gets the THD data from it in real time. The GUI runs fairly slow if you select all 64 harmonics but with 20 or less harmonics it runs fast even on my basic and slow netbook. I added a mouse/marker function to allow me to click on any harmonic to read its frequency and level etc and this is circled in blue. In the screenshot below it is looking at the spectral purity of one of my DSP based sig gens so the harmonic content is very low. I'm afraid I don't give away my programs (because I ALWAYS end up regretting it for various reasons) but maybe my GUI will give you a few starting ideas :) --- End quote --- did you have to deal with memory leak? in python 2.7, it seems in very long logs, there is something leaky :/ |
| Macbeth:
You know there is always PyVISA https://github.com/hgrecco/pyvisa :-+ |
| eas:
I tried using PyVISA before giving up on RS-232 and getting a VXI-11/GPIB gateway. PyVISA worked, but I didn't feel like I gained much, if anything, from the added complexity of the VISA layer since both RS-232 and VXI-11 were available using basic OS level functionality (serial drivers and/or TCP/IP sockets) rather than requiring a hardware specific driver like a GPIB card or USB adapter. One issue I ran into with the Keithley VISA drivers was that the really only worked at ~9600 baud or so, while raw serial access seemed reliable at much higher rates. Also, as has been mentioned, for many hardware/firmware version combinations, the Keithley 2000 has a problem that causes serial communication to die sporadically but frequently unless the RTS pin is disconnected somehow. Given that the K2015 seems to share the same motherboard as the K2000, I'd expect this to be an issue with the K2015 as well. I didn't see any obvious indication of general python memory leaks when I was running my logging script, but I'm also using a different OS and relying on different libraries. Looking at the code you published in your other topic, it looks like you don't save things to disk until you've filled a worksheet, which means it sits in memory until then. Furthermore, you don't explicitly close the worksheet/workbook when you are done with them. I'd think they'd get garbage collected at some point, but perhaps not. |
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