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Download script from 2450_IV.py
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import os
import sys
import time
import pyvisa
import numpy as np
import matplotlib.pyplot as plt
rm = pyvisa.ResourceManager()
address = None
dev_list = []
devstr = ""
inst = None
def terminate():
print("")
exit()
def pint(s, defval = None):
try:
return int(s)
except:
return defval
def pfloat(s, defval = None):
try:
return float(s)
except:
return defval
def list(is_print = True):
global dev_list
dev_list = rm.list_resources()
if is_print:
print(" Device list:", dev_list)
return dev_list
def get_devstr(addr):
global dev_list
dev_list = list(is_print = False)
# print("dev_list=", dev_list)
for s in dev_list:
aa = s.split('::')
# print("s=", s, aa)
if len(aa) < 2:
continue
if pint(aa[1]) == addr:
return s
return None
def close_device():
global inst
if inst:
inst.close()
inst = None
return True
return False
def open_device(devname):
global devstr, address, inst
close_device()
inst = rm.open_resource(devname)
if inst:
print(f" found device [{devname}]. assigned to current instrument handle")
devstr = devname
aa = devname.strip().split('::')
address = pint(aa[1])
else:
print(f" Error: Can not open device [{devname}]")
return inst
def main():
global rm, dev_list, devstr, address, inst
dev_list = list()
if len(dev_list) > 0:
inst = open_device(dev_list[0])
devname = dev_list[0]
else:
print("Error: No device found")
terminate()
if inst is None:
return
keithley = inst
keithley.write(":SENS:CURR:RANG:AUTO ON")
keithley.write(":INIT")
Vlist = []
Ilist = []
for V in np.arange(-1.0, 1.001, 0.1):
keithley.write(f":SOUR:VOLT {V:10.4g}")
V, I = ret.split(',')
V = pfloat(V)
I = pfloat(I)
Vlist.append(V)
Ilist.append(I)
print(f" set V={V:10.4g} measured V={V:14.6g} I={I:14.6g}")
# print("Current:", current)
keithley.write(":OUTP OFF")
keithley.close()
plt.plot(Vlist, Ilist)
# plt.yscale('log')
plt.show()
if __name__ == "__main__":
main()
