rs-tool.py

#!/usr/bin/env python3
# author: grey@christoforo.net
import ipaddress
import numpy
import sys
import time
import math

import k2450 # functions to talk to a keithley 2450 sourcemeter
import rs # grey's sheet resistance library

# for plotting
import matplotlib.pyplot as plt
plt.switch_backend("Qt5Agg")

# debugging/testing stuff
#visa.log_to_screen() # for debugging
#import timeit


def main():
  
  # ====for TCPIP comms====
  #instrumentIP = ipaddress.ip_address('172.17.3.60')
  instrumentIP = ipaddress.ip_address('192.168.1.204') # IP address of sourcemeter
  #fullAddress = 'TCPIP::'+str(instrumentIP)+'::INSTR'
  fullAddress = 'TCPIP::'+str(instrumentIP)+'::5025::SOCKET' # for raw TCPIP comms directly through a socket @ port 5025 (probably worse than INSTR)
  deviceTimeout = 1000 # ms
  openParams = {'resource_name': fullAddress, 'timeout': deviceTimeout, '_read_termination': u'\n'}
  
  # ====for serial rs232 comms=====
  #serialPort = "/dev/ttyUSB0"
  #fullAddress = "ASRL"+serialPort+"::INSTR"
  #deviceTimeout = 1000 # ms
  #sm = rm.open_resource(smAddress)
  #sm.set_visa_attribute(visa.constants.VI_ATTR_ASRL_BAUD,57600)
  #sm.set_visa_attribute(visa.constants.VI_ASRL_END_TERMCHAR,u'\r')
  #openParams = {'resource_name':fullAddress, 'timeout': deviceTimeout}
  
  if 'SOCKET' in fullAddress:
    rm = None
  else:
    import visa # https://github.com/hgrecco/pyvisa
    # create a visa resource manager
    rm = visa.ResourceManager('@py') # select pyvisa-py (pure python) backend
  sleepTime = 10 #s  
  
  # form a connection to our sourcemeter
  sm = k2450.visaConnect(rm, openParams)
  if sm is None:
    exit()

  # generic 2450 setup
  k2450.setup2450(sm)
  
  sweepParams = {} # here we'll store the parameters that define our sweep
  #sweepParams['maxCurrent'] = 0.005 # amps
  #sweepParams['sweepStart'] = -0.003 # volts
  #sweepParams['sweepEnd'] = 0.003 # volts
  #0.001 ua
  # for very unconductive samples
  sweepParams['maxCurrent'] = 0.00001 # amps
  sweepParams['sweepStart'] = -1 # volts
  sweepParams['sweepEnd'] = -0.5 # volts
  
  sweepParams['rangeType'] = 'BEST' # fixed, auto or best
  sweepParams['failAbort'] = 'OFF'
  sweepParams['dual'] = 'ON'
  sweepParams['nPoints'] = 21
  sweepParams['sourceFun'] = 'voltage'
  sweepParams['senseFun'] = 'current'
  sweepParams['fourWire'] = True
  sweepParams['nplc'] = 3 # intigration time (in number of power line cycles)
  sweepParams['autoZero'] = True
  sweepParams['stepDelay'] = 2 # ms (-1 for auto, nearly zero, delay)
  #sweepParams['durationEstimate'] = k2450.estimateSweepTimeout(sweepParams['nPoints'], sweepParams['stepDelay'], sweepParams['nplc'])
  
  #rOpt = {}
  #rOpt['n'] = 5
  #rOpt['fourWire'] = True
  #rOpt['nplc'] = 10
  #rOpt['sourceCurr'] = 1e-1 # amps
  #rOpt['vMax'] = 2e-4 # 20e-3, 200e-3, 2, 20 200 volts
  #rOpt['vMax'] = 200e-3
  #rOpt['vMax'] = 2e-3
  #rOpt['vMax'] = 20
  #rOpt['vMax'] = 200
  #rOpt['vMax'] = 2
  
  rsOpt = {}
  rsOpt['fourWire'] = True
  rsOpt['autoZero'] = True
  #rsOpt['nplc'] = 10
  #rsOpt['iMax'] = 5e-9
  #rsOpt['vLim'] = 50
  rsOpt['nplc'] = 1
  rsOpt['iMax'] = 1e-5
  rsOpt['vLim'] = 0.2
  rsOpt['nPoints'] = 21
  rsOpt['oCom'] = True
  rsOpt['failAbort'] = 'OFF'
  rsOpt['stepDelay'] = '-1' # in seconds, -1 is auto delay
  #rsOpt['stepDelay'] = '1' # in seconds, -1 is auto delay
  if k2450.rSweep(sm,rsOpt):
    # initiate the sweeps
    k2450.doSweep(sm)    
    [i,v,i2,v2] = k2450.fetchSweepData(sm,rsOpt)
    
    fig = plt.figure() # make a figure to put the plot into
    if i is not None:
      ax = fig.add_subplot(2,1,1)
      ax.clear()
      ax.set_title('Forward Sweep Results',loc="right")
      rs.plotSweep(i,v,ax) # plot the sweep results
      plt.show(block=False)
    
    # setup for reverse sweep
    #newEnd = sweepParams['sweepStart']
    #newStart = sweepParams['sweepEnd']
    #sweepParams['sweepStart'] = newStart # volts
    #sweepParams['sweepEnd'] = newEnd # volts
    #k2450.configureSweep(sm,sweepParams)
    #time.sleep(sleepTime)
    # initiate the reverse sweep
    #k2450.doSweep(sm)
    # get the data
    #[i,v] = k2450.fetchSweepData(sm,sweepParams)
    
    if i is not None:
      ax = fig.add_subplot(2,1,2)
      ax.clear()
      ax.set_title('Reverse Sweep Results',loc="right")
      rs.plotSweep(i2,v2,ax) # plot the sweep results
      plt.show()  
  
  print("Closing connection to sourcemeter...")
  sm.close() # close connection
  print("Connection closed.")

if __name__ == "__main__":
  main()