Live Data Acquisition Tutorial Using Python and a Keithley 2700 Multimeter 

I will paste the code below. It is organized by file. There are 3 files, find_device.py, one_shot.py, and keithley_plotter.py. I apologize, this is the easiest way for me to get the code to you. find_device.py file import pyvisa print(pyvisa.ResourceManager().list_resources()) one_shot.py file import pyvisa multimeter = pyvisa.ResourceManager().open_resource('GPIB0::1::INSTR') # Connect to the keithley and set it to a variable named multimeter. #multimeter.write(":ROUTe:CLOSe (@101)") # Set the keithley to measure channel 1 of card 1 multimeter.write(":SENSe:FUNCtion 'TEMPerature'") # Set the keithley to measure temperature #print(multimeter.query(':SENSe:DATA:FRESh?')) # Collect the most recently measured data multimeter.write(":ROUTe:OPEN:ALL") # Open all card channels and thereby set the keithley to measure the front panel inputs. print(multimeter.query(':SENSe:DATA:FRESh?')) # Collect the most recently measured data keithley_plotter.py file import pyvisa import time import matplotlib.pyplot as plt # Initialize the keithley and create some useful variables multimeter = pyvisa.ResourceManager().open_resource('GPIB0::1::INSTR')# Connect to the keithley and set it to a variable named multimeter. multimeter.write(":ROUTe:CLOSe (@101)") # Set the keithley to measure channel 1 of card 1 multimeter.write(":SENSe:FUNCtion 'TEMPerature'") # Set the keithley to measure temperature. timeList = [] # Create an empty list to store time values in. temperatureList = [] # Create an empty list to store temperature values in. startTime = time.time() # Create a variable that holds the starting timestamp. # Setup the plot plt.figure(figsize=(10,10)) # Initialize a matplotlib figure plt.xlabel('Elapsed Time (s)', fontsize=24) # Create a label for the x axis and set the font size to 24pt plt.xticks(fontsize=18) # Set the font size of the x tick numbers to 18pt plt.ylabel('Temperature ($^\circ$C)', fontsize=24) # Create a label for the y axis and set the font size to 24pt plt.yticks(fontsize=18) # Set the font size of the y tick numbers to 18pt # Create a while loop that continuously measures and plots data from the keithley forever. while True: temperatureReading = float(multimeter.query(':SENSe:DATA:FRESh?').split(',')[0][:-2]) # Read and process data from the keithley. temperatureList.append(temperatureReading) # Append processed data to the temperature list timeList.append(float(time.time() - startTime)) # Append time values to the time list time.sleep(0.5) # Interval to wait between collecting data points. plt.plot(timeList, temperatureList, color='blue', linewidth=10) # Plot the collected data with time on the x axis and temperature on the y axis. plt.pause(0.01) # This command is required for live plotting. This allows the code to keep running while the plot is shown.

I use notepad++ and then I made a hotkey to run the code in Python (Anaconda)

I unfortunately don't have experience with RS-232 communications with the Keithleys. Any chance you can get ahold of a GPIB-USB cable?

Keithley/Tektronix has examples of controlling RS232 instruments via PyVisa. You should be able to find something in the examples for the DAQ6510, which is the successor to the 2700 and 2701.

The Keithley 2400 Sourcemeter uses some different SCPI commands. The overall python code structure will be the same but the commands you send over pyvisa will likely be a bit different. Take a look at the manual for the Keithley 2400 and look for the "one shot" measurement examples.

@@jesseadamczyk1745 Thanks so much for the reply man.

Hi Ahmad, are you using a special card in the back of the 2750 DMM? Perhaps the 7709 matrix card?

For Error 113, it says "Undefined Header". I am not quite sure what this means. 2182A is a little bit different for some reason. Try this code below but change the GPIB address to whatever is on your 2182A. If this does not work, send me a DM and I'll send you a python class I wrote for the 2182a. You'll be able to figure it out from there. import time import visa # Setup the instrument instrument = visa.ResourceManager().open_resource('GPIB ADDRESS GOES HERE') time.sleep(0.05) instrument.timeout = 30000 time.sleep(0.05) # Setup voltage measurement instrument.write(':SENSe:CHANnel 1') instrument.write(':SENSe:FUNCtion "VOLTage:DC"') instrument.write(':SENSe:VOLTage:DC:RANGe:AUTO ON') instrument.write(':SENSe:VOLTage:DC:NPLC 1') instrument.write('TRIGger:COUNt 1') # Take the voltage measurement voltage = self.instrument.query(':SENSe:DATA:FRESh?')

@@jesseadamczyk1745 Thank you so much! This fixed that error code.

Yes, the same commands or very similar should work.

Yes, that is possible. You will need to some extra setup though. I pasted some code from a python class I wrote specifically for collecting temperature and voltage at the same time (Seebeck measurements). I'm sorry for the poor formatting. Please paste the code into your IDE or notepad++ so it doesn't look so awful. If you want to run this code, you will have to remove the "self" in front of everything. If you were able to follow along with the video, you'll be able to edit the below code and get it working. You can see from the commented code that I'm setting channels 111 to 120 along with 211 and 212 to measure voltage. Channels 101 through 110 along with 201 and 202 are set to measure temperature. def continuousScanSetup(self): self.instrument.write("*RST") # Reset to defaults for this time.sleep(0.05) self.instrument.write(':SYSTem:BEEPer:STATe OFF') # Turn off the beeper. This has to be done again here because of *RST time.sleep(0.05) self.instrument.write(":TRACe:CLEar") # Clear the buffer time.sleep(0.05) #self.instrument.write(":FORMat:ELEMents CHANnel, READing, UNITs, RNUMber, TSTamp") # Format the output. These are not in order unfortunately because Keithley is setup that way. self.instrument.write(":FORMat:ELEMents CHANnel, READing, UNITs") # Format the output to include channel, reading, and units time.sleep(0.05) self.instrument.write(":INITiate:CONTinuous OFF") # Turn off continuous initiation time.sleep(0.05) self.instrument.write(":TRIGger:SOURce IMMediate") # Start scanning immediately after triggering occurs. No delays. time.sleep(0.05) self.instrument.write(":TRIGger:COUNt 1") # This is the number of times that triggering will occur. time.sleep(0.05) self.instrument.write(":SAMPle:COUNt 110000") # time.sleep(0.05) self.instrument.write(":FUNCtion 'VOLT', (@111:120,211,212)") # Set channels to measure voltage. time.sleep(0.05) self.instrument.write("VOLTage:NPLC 1, (@111:120,211,212)") time.sleep(0.05) self.instrument.write(":FUNCtion 'TEMP', (@101:110,201,202)") # Set channels to measure temperature. time.sleep(0.05) self.instrument.write("TEMPerature:NPLC 1, (@101:110,201,202)") time.sleep(0.05) self.instrument.write(":ROUTe:SCAN (@101:120,201,202,211,212)") # Set channels to be scanned. time.sleep(0.05) self.instrument.write(":ROUTe:SCAN:TSO IMM") # Scan source immediately? time.sleep(0.05) self.instrument.write(":ROUTe:SCAN:LSEL INT") time.sleep(0.05) return "Scan setup complete" Here are the other functions I used with the above function: def initiateContinuousScan(self): self.instrument.write(":INITiate:Immediate") # Start scanning immediately. return 'scan initiated' def readBuffer(self): data = self.instrument.query("TRACe:DATA?") return data

@@jesseadamczyk1745 Hi Jesse, thank you for your tutorial and your code. I am, unfortunately, a beginner in this and I have problems reading multiple channels. I want to read the VDC of several channels continuously. However, if I do instrument.write(":ROUTe:MULTiple:CLOSe (@101:102)"), it never is able to scan both channels seperately. DO you have any idea how I can fix that and how the output will be? Do I need to do a "for" with the string and seperate the two channels as output. The handbook is not that clear how the output is given for several channels.

Please see the link in the description!

No, the video is only for GPIB protocol

@@omunoz meanwhile I tried it myself and it is working. GPIB is not a protocol. It is a hardware interface. The protocol is called SCPI. You can replace the interface easily with Ethernet, serial or whatever the device supports

@@MarkusBurrer Are you using Ethernet cable instead of GPIB cable to the PC

@@NiteshKumar-ss4gg yes.

@@MarkusBurrer If i use USB to send the commands will it work?

I have never done this sort of measurement before, so I will only be so much help. If you can get python to read a frequency from the Keithley 2700, then you should be able to append the frequency value to a list of frequency values. Then using matplotlib, you would need to plot the frequency values on the x-axis and your other values on the y-axis. It would be something like: plt.plot(frequencyList, otherList)

I have not used this exact model of connector before. This seems like a Python issue, but here are a few things I would try: 1) If there are lights on the connector, check to make sure that they are the correct colors (i.e. connected vs fail etc) 2) Restart your computer. Sometimes the driver installation/USB connections magically get fixed after you do this. 3) Make sure PyVisa is installed correctly with "pyvisa-info" in the command prompt/terminal. 4) Try another GPIB-USB connector if you have one lying around. I have had these connectors die randomly once in a while. 5) Try installing pyvisa-py (pip install pyvisa-py) and use that instead of pyvisa. Sometimes this works but I'm not quite sure why. Best of luck!

@@jesseadamczyk1745 Thank you for your awesome support !!! :) In the meantime, I have changed connector with a 9 pin to USB and it worked ! But I will definitely try again the first connector with your guidance ! Thank you Jesse

I used the Keysight Instrument Control Bundle here: www.keysight.com/us/en/lib/software-detail/computer-software/keysight-instrument-control-bundle-download-1184883.html

The GPIB address is set to 01 on the multimeter because it is also set to 1 in the python code address: "GPIB0::1::INSTR"

@@jesseadamczyk1745 Thanks for replying!

Yes, this should work almost the same. You may have to play with the channels commands as I don't think the 2001 has the same style of card to install in the back.

@@jesseadamczyk1745 Thank you so much for your reply dear Jesse. I have no idea about it's input channels card, but I want to record from its panel inputs only.

@@jesseadamczyk1745 Dear Jesse, I have Keithley 2001. I want to set up a Data logging system using python and keysight gpib adapter. How code should be written in python in order to acquire data at specified intervals ? I don't want plot I need only saved readings.

Hi Joseph, For the thermocouple type, I have never set this via the code. I have only ever set this by the front panel controls of the Keithley. Page 3-50, table 3-7 of the Keithley 2700 manual shows the commands you would use to change the different thermocouple types. I am working on a new video that will cover scanning multiple thermocouples and sources at once. Here is a python script that will help you with your long/short plotting. I'll comment this up for the new video soon, but right now you can see how it works. Let me know if it does not work. import matplotlib.pyplot as plt import time import numpy as np fig, (ax1, ax2) = plt.subplots(1,2, figsize=(8,4)) ax1.set_xlabel('Total elapsed time (s)') time_list = [] sin_list = [] start_time = time.time() while True: current_time = time.time() - start_time time_list.append(current_time) sin_list.append(np.sin(current_time)) ax1.plot(time_list, sin_list, color='blue') if len(time_list) >= 10: plt.cla() ax2.plot(time_list[-10:], sin_list[-10:], color='red') ax2.set_xlabel('Last 10 measurements') if len(time_list) < 10: ax2.plot(time_list, sin_list, color='red') ax2.set_xlabel('Last 10 measurements') plt.pause(0.1) if time_list[-1] >=20: break

Link to Keithley 2700 Manual: download.tek.com/manual/2700-900-01K_Feb_2016.pdf

@@jesseadamczyk1745 Hi Jesse, Thank you! I really appreciate you taking the time to respond in detail. This information is very helpful. I am playing around with the thermocouple type. The one issue I see is I am having trouble figuring out if I can set different channels to different thermocouple types. What do you mean by setting the specific thermocouple type for the channels on the front panel? Thank you for including the manual. That would be awesome! I really look forward to seeing your new video on this. Do you know if it's possible to set the scan rate? If the default is the fastest possible then that is fine. Thank you for sharing your python script, I really appreciate you doing that. I am going to try it today and I will make sure to let you know if it works. Thank you for all of your help Jesse!

Hi Jesse, I just wanted to follow up. No worries if you are too busy!