def run_simple(self, bias, gateLim, avg = 6.0, field = 0.0, runs = 1,
cvResistor = 1.0, cvAmp = 1.0, gateAmp = 9.1788,
measDelay = 0.1, gateDelay = 1.0, nplc = 1, nvmRange = 0.1):
""" This runs the actual experiment. It can be called independently of the
run() function. """
tools.write_log('fixBias_swpGate', locals(), self.filename+'.log')
source = keithleypair.FixedBias("GPIB::22", timeout = 60.0) #keithley object
daqGate = nidaqmx.AnalogOutputTask() #DAQ output object
daqGate.create_voltage_channel('Dev1/ao0', min_val = -10.0, max_val = 10.0)
gateBuffer = tools.get_buffer_size(gateLim[0], gateLim[1], gateLim[2])
gates = np.linspace(gateLim[0], gateLim[1], gateBuffer)
#setup 6220/2182A
source.general_setup()
source.bias_setup(bias/cvResistor)
source.voltmeter_channel_setup(nplc, nvmRange)
source.single_point_setup(avg, measDelay)
#check that everything is setup
print "current source state: ", source.source_chk_op_evnt_reg()
print "voltmeter state: ", source.voltmeter_chk_meas_evnt_reg()
source.write(":outp 1")
time.sleep(2.0)
data = np.zeros(gateBuffer)
for run in range(runs):
end = False
for i, gate in enumerate(gates):
daqGate.write([gate/gateAmp])
time.sleep(gateDelay)
data[i] = source.get_meas()
data[i] = data[i]*cvAmp
np.savetxt(self.file, [[gate, data[i], run+1]], fmt = '%+.6e', delimiter = '\t')
self.file.flush(); os.fsync(self.file)
if msvcrt.kbhit():
if ord(msvcrt.getch()) == 113:
end = True
print "Program ended by user.\n"
break
if end: break
gates = gates.reshape(-1)[::-1] #sweep in the other direction
data.fill(0.0)
print 'Cleaning up...'
source.write(":outp 0") #turn off current source
source.close()
daqGate.write([0.0]) #turn off gate
del daqGate, source #delete DAQ object so it can be reused
self.file.close()
def run(
self,
bias,
points=100,
gateDelay=0.75,
cvResistor=10.0,
cvAmp=-1e-7,
gateAmp=1.0,
nplc=1,
nvmRange=1.0,
filename="roomTemp_cntTest_{0:.0f}".format(time.time()),
):
""" This runs the actual experiment. It can be called independently of the
run() function. """
tools.write_log("gateTest_vBias_", locals(), filename + ".log.txt")
file = open(filename + ".dat.txt", "a")
self.end_run = False
self.start_run = False
source = keithleypair.FixedBias("GPIB::22", timeout=60.0) # keithley object
self.data = np.zeros((points, 4))
# setup 6220/2182A
source.general_setup()
source.bias_setup(bias / cvResistor, analogFilt=True)
source.voltmeter_channel_setup(nplc, nvmRange, digital_filter=False)
source.bus_trig_setup(points)
# check that everything is setup
print "current source state: ", source.source_chk_op_evnt_reg()
print "voltmeter state: ", source.voltmeter_chk_meas_evnt_reg()
# ramp up bias voltage
if bias < 0:
c = -1.0
else:
c = 1.0
for i in range(-9, 0):
outp = c * 2 * math.pow(10, i)
if abs(outp) > abs(bias):
source.write(":sour:curr {0:.15f}".format(bias / cvResistor))
time.sleep(1.0)
break
else:
source.write(":sour:curr {0:.15f}".format(outp / cvResistor))
if i == -9:
source.write("outp 1")
time.sleep(1.0)
print "wait for stable current..."
time.sleep(5.0)
# run experiment
print "GO!"
start_time = time.time()
for i in range(points):
time.sleep(gateDelay)
source.write_serial("*TRG")
self.data[i, 0] = time.time() - start_time
if (msvcrt.kbhit() and ord(msvcrt.getch()) == 113) or self.end_run:
print "Program ended by user."
break
self.data[:, 1] = source.read_2182A_buffer()
self.data[:, 2] = self.data[:, 1] * cvAmp
self.data[:, 3] = bias / self.data[:, 2]
np.savetxt(file, self.data, fmt="%+.6e", delimiter="\t")
# ramp down bias voltage
print "Turning off bias..."
for i in range(0, 10):
outp = c * 2 * math.pow(10, -i)
if abs(outp) > abs(bias):
continue
else:
source.write(":sour:curr {0:.15f}".format(outp / cvResistor))
time.sleep(1.0)
source.write(":outp 0") # turn off current source
source.close() # close gpib instrument
del source # delete DAQ object so it can be reused
file.close()
print "Done."
fig = plt.figure()
ax = fig.add_subplot(111)
ax.grid(True)
title_text = plt.title("bias = {0:+.2e}V".format(bias))
line, = ax.plot(self.data[:, 0], self.data[:, 2], "r-o")
plt.xlabel("time (s)")
plt.ylabel("current (A)")
plt.show()
self.end_run = True
def run_simple(
self,
bias,
avg=1.0,
field=0.0,
cvResistor=10.0,
cvAmp=-1e-7,
gateAmp=1.0,
measDelay=0.1,
gateDelay=0.75,
nplc=1,
nvmRange=1.0,
filename="roomTemp_cntTest_{0:.0f}".format(time.time()),
):
""" This runs the actual experiment. It can be called independently of the
run() function. """
tools.write_log("gateTest_vBias_", locals(), filename + ".log.txt")
file = open(filename + ".dat.txt", "a")
self.end_run = False
self.start_run = False
source = keithleypair.FixedBias("GPIB::22", timeout=60.0) # keithley object
daqGate = nidaqmx.AnalogOutputTask() # DAQ output object
daqGate.create_voltage_channel("Dev1/ao1", min_val=-10.0, max_val=10.0)
gat = np.arange(0, 10.25, 0.25)
gates = np.append(gat, [gat[::-1], -gat, -gat[::-1]])
self.data = np.zeros((len(gates), 3))
# setup 6220/2182A
source.general_setup()
source.bias_setup(bias / cvResistor, analogFilt=False)
source.voltmeter_channel_setup(nplc, nvmRange, digital_filter=False)
source.single_point_setup(avg, measDelay)
# check that everything is setup
print "current source state: ", source.source_chk_op_evnt_reg()
print "voltmeter state: ", source.voltmeter_chk_meas_evnt_reg()
# ramp up bias voltage
if bias < 0:
c = -1.0
else:
c = 1.0
for i in range(-9, 0):
outp = c * 2 * math.pow(10, i)
if abs(outp) > abs(bias):
source.write(":sour:curr {0:.15f}".format(bias / cvResistor))
time.sleep(1.0)
break
else:
source.write(":sour:curr {0:.15f}".format(outp / cvResistor))
if i == -9:
source.write("outp 1")
time.sleep(1.0)
print "wait for stable current..."
time.sleep(5.0)
# run experiment
exitGate = 0.0
print "GO!"
for i, gate in enumerate(gates):
daqGate.write(gate / gateAmp)
time.sleep(gateDelay)
self.data[i, 0] = gate
self.data[i, 1] = source.get_meas() * cvAmp
self.data[i, 2] = bias / self.data[i, 1]
np.savetxt(file, [self.data[i]], fmt="%+.6e", delimiter="\t")
if (msvcrt.kbhit() and ord(msvcrt.getch()) == 113) or self.end_run:
exitGate = gate
print "Program ended by user."
break
if i == 2:
self.start_run = True
# ramp down bias voltage
print "Turning off bias..."
for i in range(0, 10):
outp = c * 2 * math.pow(10, -i)
if abs(outp) > abs(bias):
continue
else:
source.write(":sour:curr {0:.15f}".format(outp / cvResistor))
time.sleep(1.0)
# ramp down back gate
print "Turning off gate..."
while True:
if abs(exitGate) < 1.0:
break
if exitGate < 0:
exitGate += 1.0
else:
exitGate -= 1.0
if abs(exitGate) < 1.0:
break
else:
daqGate.write(exitGate / gateAmp)
time.sleep(0.5)
source.write(":outp 0") # turn off current source
source.close() # close gpib instrument
daqGate.write(0.0) # turn off gate, should already be at 0
daqGate.clear()
del daqGate, source # delete DAQ object so it can be reused
file.close()
print "Done."
def run_simple(self, bias, samples = 1.0, gateDelay = 0.75, field = 0.0,
biasDivider = 1e-3, cvAmp = -1e-6, gateAmp = 9.1788,
filename = 'DAQIO_gateTest_{0:.0f}'.format(time.time())):
""" This runs the actual experiment. It can be called independently of the
run() function. """
tools.write_log('DAQIO_gateTest', locals(), filename+'.log.txt')
file = open(filename+'.dat.txt','a')
self.end_run = False
#setup output channels
bias_channel = 'Dev1/ao0'
bias_out = nidaqmx.AnalogOutputTask()
bias_out.create_voltage_channel(bias_channel, min_val = -10.0, max_val = 10.0)
gate_channel = 'Dev1/ao1'
gate_out = nidaqmx.AnalogOutputTask()
gate_out.create_voltage_channel(gate_channel, min_val = -10.0, max_val = 10.0)
gat = np.arange(0,10.1,0.1)
gates = np.append(gat, [gat[::-1], -gat, -gat[::-1]])
self.data = np.zeros((len(gates), samples+3))
sample_data = np.zeros((samples,1))
#setup input channel
input_channel = 'Dev1/ai0' #if using differential mode this should be the high side
sample_rate = 5000
itask = nidaqmx.AnalogInputTask()
itask.create_voltage_channel(input_channel, terminal = 'diff', min_val = -10.0, max_val = 10.0)
itask.configure_timing_sample_clock(rate = sample_rate, samples_per_channel = samples,
sample_mode = 'finite')
itask.alter_state('commit')
print 'bias turning on...'
bias_out.write(bias/biasDivider)
time.sleep(10.0)
#run experiment
exitGate = 0.0
print 'GO!'
for i, gate in enumerate(gates):
itask.start()
gate_out.write(gate/gateAmp)
time.sleep(gateDelay)
sample_data = itask.read()
itask.wait_until_done()
itask.stop()
self.data[i,0] = gate
self.data[i,1] = sample_data.mean()*cvAmp
self.data[i,2] = bias/self.data[i,1]
self.data[i,3:] = sample_data.transpose()
np.savetxt(file, [self.data[i]], fmt = '%+.6e', delimiter = '\t')
if (msvcrt.kbhit() and ord(msvcrt.getch()) == 113) or self.end_run:
exitGate = gate
print "Program ended by user."
break
bias_out.write(0.0)
bias_out.clear()
gate_out.write(0.0) #turn off gate, should already be at 0
gate_out.clear()
del gate_out, bias_out #delete DAQ object so it can be reused
file.close()
print 'Done.'
