Clary Andrea

See if this application note helps:
Four Point Probe Resistivity with 2450

You have two keithleys and two gpib cables.
But how many GPIB interface boards does the computer have?
If only one gpib card in the PC, then only one program can take charge of it at a time.
A single program that sends commands to two different gpib address would be needed for simultaneous use of both keithleys.

The model 2701 uses port 1394 for the LAN communication.

You can try turning off the display:   :DISPLAY:ENABLE:STAT OFF

I found an FAQ on tek.com for this topic.  It is indicating that the TRACE buffer is not the fastest one.

Max Reading Rate from 2700, 2701 or 2750

Alternate commands:

*RST

:SENSE:FUNC 'VOLT:DC'

:SENSE:VOLT:NPLC 0.01

:SENSE:VOLT:RANGE 10

:SENSE:VOLT:AVER:STAT OFF

:SAMPLE:COUNT 1000

:TRIG:DELAY 0.0

:SYSTEM:AZERO:STAT OFF

:DISPLAY:ENABLE:STAT OFF

:READ?

Now read the data...

To check for maximum speed apply a 1V RMS at 2Hz to the input. Run the above command sequence.

The 1000 readings should show one complete cycle or less. This shows the meter is taking data at least at a rate of 2000 readings per second.

Here is some Python sample code for scanning some channels with model 3706A:

import pyvisa                                              
import time                                                
import matplotlib.pyplot as plt                
import pandas as pd


def check_error():
    status = my3706A.read_stb()
    if int(status) & 4 == 4 :    #test if the EAV (error available) bit is set
        error_response = my3706A.query("print(errorqueue.next())")
        print(error_response)
    else:
        print("No Errors")

def get_scanState():
    my3706A.write("scanState, scanCount, stepCount, lastReading = scan.state()")
    return int(float(my3706A.query("print(tonumber(scanState))")))
   

DEBUG = 0
my3706A = pyvisa.ResourceManager().open_resource('TCPIP0::192.168.1.214::INSTR')
#my3706A = pyvisa.ResourceManager().open_resource('USB0::0x05E6::0x3706::04428124::INSTR') # Connect to the keithley and set it to a variable named multimeter.
my3706A.timeout = 10000  #number of msec to wait for VISA command completions
#my3706A.write("")
#put instrument into known state
my3706A.write('reset()')
my3706A.write('status.reset()')
my3706A.write('errorqueue.clear()')
#allocate a buffer for the measurements
my3706A.write('buf=dmm.makebuffer(1000)')
my3706A.write('buf.clear()')
my3706A.write('buf.appendmode=1')
my3706A.write('buf.collectchannels=1')

if DEBUG: check_error()
#configure the DMM settings
my3706A.write("dmm.func= dmm.DC_VOLTS")  #   TWO_WIRE_OHMS   DC_VOLTS
my3706A.write("dmm.range=1")
my3706A.write("dmm.autorange=1")
my3706A.write("dmm.nplc= 1")   #0.0005 to 15 for 60Hz power
my3706A.write("dmm.autozero= dmm.ON")
my3706A.write("dmm.autodelay= dmm.ON")

if DEBUG: check_error()
#associate these dmm settings with a configuration name
# do not use a factory preset name, e.g., 'dcvolts'
# custom settings = requires custom name
my3706A.write('dmm.configure.set("my_dcvolts")')

if DEBUG: check_error()
#associate the dmm config with channels
my3706A.write('dmm.setconfig("1001:1008", "my_dcvolts")')


#define a scan
my3706A.write('scan.measurecount=1')  # one reading per scan
my3706A.write("scan.create('1001:1008')")
my3706A.write("scan.scancount = 10")     # 10 scans
# now that scan is setup, run the scan
my3706A.write("buf.clear()")   # just in case, clear the buffer of any content
#my3706A.write("scan.execute(buf)")  # this one does not return until scan completes
my3706A.write("scan.background(buf)")  # this one returns;  Python needs to coordinate with done.

# setup a while loop to exit when scan state goes to 6 = scan.SUCCESS = done
script_running = True
DEBUG_LOOP = 0
while script_running:
    present_state = get_scanState()
    if DEBUG_LOOP: print("Scan State: " + str(present_state))
    if present_state == 6:
        script_running = False
    time.sleep(0.5) #delay before asking again

#ask for the data
my3706A.write("printbuffer(1, buf.n, buf.relativetimestamps, buf.readings)")
raw_data = my3706A.read()
# raw data will be comman delimited string:
# time, ch1, time, ch2, time, ch3, time, ch4, time, ch5, time...
# parse the data
raw_data_array = raw_data.split(",")
timestamps = []
chan1001 = []
chan1002 = []
chan1003 = []
chan1008 = []
num_channels = 8
num_elements = num_channels * 2  #time, ch1, time, ch2, time, ch3, time, ch4, time, ch5, time....
for element in range(0, len(raw_data_array), num_elements):
    timestamps.append(float(raw_data_array[element]))
    chan1001.append(float(raw_data_array[element+1]))
    chan1002.append(float(raw_data_array[element+3]))
    chan1003.append(float(raw_data_array[element+5]))
    chan1008.append(float(raw_data_array[element+15]))
#create dataframe
data = {'Timestamp': timestamps, 'Channel 1': chan1001, 'Channel 2': chan1002, 'Channel 3': chan1003, 'Channel 8': chan1008}
df = pd.DataFrame(data)

# Set 'Timestamp' as the index
df.set_index('Timestamp', inplace=True)
# Print the DataFrame
print(df)
# ********************  Simple Graph ******************
plt.figure()
plt.subplot(3, 1, 1) # nrows=3, ncols=1, index=1
plt.plot(timestamps, chan1001, 'o-b')
plt.subplot(312)
plt.plot(timestamps, chan1002, 'x-r')
plt.subplot(313)
plt.plot(timestamps, chan1003, '.-g')
plt.show()


my3706A.clear()
my3706A.close()

The electrochemistry scripts for use with 2450, 2460 or 2461 are not open source.

The scripts can be obtained on model number EC-UPGRADE

EC-UPGRADE Kit Quick Start Guide

In attached document, is more info and a sample TSP script.

On each of the DB78 connectors on the 3720 card, there are the +ILK and -ILK pins.
Make sure to jumper these two pins together to enable the closure of the backplane relay.

NOTE:  when using the 3720-ST wiring accessory, these jumpers are made for you.

The IVI driver did not define a means to query that information from the card.
The IVI driver does however have WriteString and ReadString as part of the DirectIO interface.

//ask for closure counts from a channel list 
driver.System.DirectIO.WriteString("print(channel.getcount(\"1001,1911\"))");
                
resultsListBox.Items.Add(driver.System.DirectIO.ReadString());

 

Hello,
Please elaborate on the sweep until it finds a drop in current.  Is the sweep implemented as a loop controlled from LabVIEW?  And the LV code is where the evaluation about current drop occurs?