class AnalogMFC(object):
""" Driver for controling an analog MFC (or PC) with
an AB Electronics ADCDAC """
def __init__(self, channel, fullrange, voltagespan):
self.channel = channel
self.fullrange = fullrange
self.voltagespan = voltagespan
self.daq = ADCDACPi() # create an instance of ADCDACPi
self.daq.set_adc_refvoltage(3.3)
def read_flow(self):
""" Read the flow (or pressure) value """
value = 0
for _ in range(0, 10): # Average to minimiza noise
value += self.daq.read_adc_voltage(1)
value = value / 10
#print('Value: ' + str(value))
flow = value * self.fullrange / self.voltagespan
return flow
def set_flow(self, flow):
""" Set the wanted flow (or pressure) """
voltage = flow * self.voltagespan / self.fullrange
print('Voltage: ' + str(voltage))
self.daq.set_dac_voltage(1, voltage)
return voltage
def complextriangle(period):
period = period * 2
#complex triangle wave
def f1(t,period,slope):
t=t%period
if (t<=period/5 or t>=4*period/5):
t=t%(period/15)
if (t<=period/30):
output = slope * t
else:
output = 1.0/3 - slope * (t-period/30)
elif (t<=2*period/5 or t>=3*period/5):
t=t%(period/15)
if(t<=period/30):
output = 2 * slope * t
else:
output = (2.0/3) - 2* slope * (t-period/30)
else:
t=t%(period/15)
if(t<=period/30):
output = 3 * slope * t
else:
output = 1 - 3 * slope * (t-period/30)
return output
t0=time.time()
t=0
out=0
n=0
i=0
period=.5*period
slope1 = (1.0/3)/(period/30) #calculated from the period
#initialize DAC
dac=ADCDACPi()
#infinite loop
print "Press ENTER to quit.\n"
while(True):
#exit when user presses enter
if sys.stdin in select.select([sys.stdin],[],[],0)[0]:
line = raw_input()
break
#get time
t=time.time()-t0
#make signal bipolar
if ((t//period)%2)==1:
out=f1(t,period,slope1)
dac.set_dac_voltage(1,.55*out)
else:
out=f1(t,period,slope1)
dac.set_dac_voltage(2,.55*out)
def simpletriangle(period): period=period * 2 #simple triangle wave def f(t,period,slope): t=t%(period/3) if t<=period/6: output = slope * t else: output = 1 - slope * (t-period/6) return output t0=time.time() t=0 out=0 n=0 i=0 period=.5*period slope2 = 1.0/(period/6) #initialize DAC dac=ADCDACPi() #infinite loop print "Press ENTER to quit.\n" while(True): #exit when user presses enter if sys.stdin in select.select([sys.stdin],[],[],0)[0]: line = raw_input() break #get time t=time.time()-t0 #make signal bipolar if ((t//period)%2)==1: out=f(t,period,slope2) dac.set_dac_voltage(1,.55*out) else: out=f(t,period,slope2) dac.set_dac_voltage(2,.55*out)
#!/usr/bin/python
from ABE_ADCDACPi import ADCDACPi
import time
"""
================================================
ABElectronics ADCDAC Pi 2-Channel ADC, 2-Channel DAC | DAC Write Demo
Version 1.0 Created 17/05/2014
Version 1.1 16/11/2014 updated code and functions to PEP8 format
run with: python demo-dacwrite.py
================================================
this demo will generate a 1.5V p-p square wave at 1Hz
"""
adcdac = ADCDACPi()
while True:
adcdac.set_dac_voltage(1, 1.5) # set the voltage on channel 1 to 1.5V
time.sleep(0.5) # wait 0.5 seconds
adcdac.set_dac_voltage(1, 0) # set the voltage on channel 1 to 0V
time.sleep(0.5) # wait 0.5 seconds
# set voltage to X volts
start = float(raw_input("Enter a starting voltage below 0.4 volts, then press [Enter]"))
while startV_flag == 1:
if start > 0.4:
start = float(raw_input("Incorrect, please enter a starting voltage below 0.4 volts, then press [Enter]"))
elif start < 0.0:
start = float(raw_input("Incorrect, please enter a positive value, then press [Enter]"))
else:
startV_flag = 0
high = float(raw_input("Enter a max voltage up to 0.4 volts, then press [Enter]"))
while maxV_flag == 1:
if high > 0.4:
high = float(raw_input("Incorrect, please enter a max voltage up to 0.4 volts, then press [Enter]"))
elif high < 0.0:
high = float(raw_input("Incorrect, please enter a positive value, then press [Enter]"))
else:
maxV_flag = 0
# start test
raw_input("Press [Enter] to begin the test")
adcdac.set_dac_voltage(1, start) # set the voltage on channel 1 to 1.5V
# set to max voltage
raw_input("press [Enter] to set DAC %0.3f volts" %high)
adcdac.set_dac_voltage(1, high) # set the voltage on channel 1 to 1.5V
# back to start voltage
raw_input("press [Enter] to set DAC back to %0.3f volts" %start)
adcdac.set_dac_voltage(1, start) # set the voltage on channel 1 to 1.5V
# set to Zero volts
raw_input("press [Enter] to set DAC to 0 volts")
adcdac.set_dac_voltage(1, 0)
Version 1.1 16/11/2014 updated code and functions to PEP8 format
run with: python demo-dacwrite.py
================================================
this demo will generate a 1.5V p-p square wave at 1Hz
"""
# The ADCDAC Pi uses GPIO pin 22 to control the DAC.
# This will need to be turned off for the DAC to operate correctly.
GPIO.setwarnings(False)
GPIO.setmode(GPIO.BOARD)
GPIO.setup(22, GPIO.OUT)
GPIO.output(22, False)
adcdac = ADCDACPi(1) # create an instance of the ADCDAC Pi with a DAC gain set to 1
# set voltage to X volts
adcdac.set_dac_voltage(1, 0.401) # set the voltage on channel 1 to 1.5V
raw_input("press [Enter] to set DAC back to 0 volts")
adcdac.set_dac_voltage(1, 0)
# toggle
#while True:
# adcdac.set_dac_voltage(1, 1.5) # set the voltage on channel 1 to 1.5V
# time.sleep(0.5) # wait 0.5 seconds
# adcdac.set_dac_voltage(1, 0) # set the voltage on channel 1 to 0V
# time.sleep(0.5) # wait 0.5 seconds
class DetectPi:
def __init__(self):
'''
Initialise ADC-DAC Pi. The DAC gain factor is set to 1, which allows
the DAC output voltage to be set between 0 and 2.048 V. The DAC gain
factor may also be set to 2, which gives an output range of 0 to 3.3 V.
'''
# Create instance of ADCDACPi, with gain set to 1
self.adcdac = ADCDACPi(1)
# Set reference voltage to 3.3 V
self.adcdac.set_adc_refvoltage(3.3)
return
def getDetails(self):
'''
Return details of ADC_DAC Pi. This function does not currently return
any details, but this may change later.
'''
return
def writePort(self, Port, Volt):
'''
Write values to a DAC pin. Values may be written to either channel 1
or channel 2. The maximum voltage is specified by the gain factor.
Note: Setting a voltage of 5 V will return an error for exceeding
the maximum voltage.
'''
# Ensure port is of type list
if type(Port) == str:
Port = [Port]
# Convert DAQT7 DAC ports to DAC Pi channels
if "DAC0" in Port:
channel = 1
elif "DAC1" in Port:
channel = 2
# Set DAC output voltage <Volt> on channel <channel>
self.adcdac.set_dac_voltage(channel, Volt)
return
def readPort(self, Port):
'''
Read values from an ADC pin. Values may be read from either channel 1
or channel 2.
'''
# Ensure port is of type list
if type(Port) == str:
Port = [Port]
# Convert DAQT7 AIN ports to ADC Pi channels
if "AIN0" in Port:
channel = 1
elif "AIN1" in Port:
channel = 2
# Read voltage from channel <channel> in single ended mode
voltRead = self.adcdac.read_adc_voltage(channel, 0)
return np.float(voltRead), time.time()
def streamRead(self, scanRate, scansPerRead, Port):
'''
Read analogue input values from an ADC pin, in stream mode.
'''
# Ensure port is of type list
if type(Port) == str:
Port = [Port]
# Initialise array and time values
Read = [0, 1, 2]
StartingMoment = 0
FinishingMoment = 0
scansPerRead = int(scansPerRead)
# Determine timing characteristics
duration = scansPerRead / float(scanRate)
dt = 1 / float(scanRate)
StartingMoment = time.time()
# Allow for alternation between multiple ports
portIndex = 0
portLength = len(Port)
# Loop for the duration
while (time.time() - StartingMoment) < duration:
# Read the ADC value and append to an array
voltRead = self.readPort(Port[portIndex])[0]
Read[0].append(voltRead)
portIndex = (portIndex + 1) % portLength
# Wait for the program to run at the correct frequency
lastReadTime = readTime
readTime = time.time()
if readTime - lastReadTime < dt:
time.sleep(dt - readTime + lastReadTime)
# Calculate and print elapsed time
FinishingMoment = time.time()
print('Elapsed time %f seconds' % (FinishingMoment - StartingMoment))
return Read, StartingMoment, FinishingMoment
def close(self):
'''
Close ADC-DAC Pi.
'''
pass
def main(args):
user_input = sys.argv
startV = float(user_input[1])
maxV = float(user_input[2])
# lowV = float(user_input[3])
# endV = float(user_input[4])
print("User has typed in : %s" %user_input)
print("Test starts at %.3f volts" %startV)
print("Test peaks at %.3f volts" %maxV)
# initialize
adcdac = ADCDACPi(1) # create an instance of the ADCDAC Pi with a DAC gain set to 1
adcdac.set_adc_refvoltage(3.3) # powered off 3.3V GPIO rail
# TODO: add in sample number
csv_filename, test_csv = open_csv(1)
# Hardware settings/references
shunt_resistor = 10 # 10 Ohms
# High-Side Current Monitor IC
gain = 500
# DAC Vref = 2.048v internal
# ADC Vref = Vdd = 3.3v
# start test
raw_input("Press [Enter] to view Conditions")
adcdac.set_dac_voltage(1, startV) # set the voltage on channel 1
voltage = startV
# 1mV increments
# init = int(startV*1000)
# peak = int(maxV*1000)
# 10mV increments
init = int(startV*100)
peak = int(maxV*100)
count = 0
print("START is %0.3f VOLTS" %voltage)
print("HIGH is %0.3f VOLTS" %maxV)
print("INIT is %0.3f UNITS" %init)
print("PEAK is %0.3f UNITS" %peak)
raw_input("Press [Enter] to begin the test")
# ramp up
for i in range (init, peak, 1):
adcdac.set_dac_voltage(1, voltage)
# read channel 1 in single ended mode
voltage_reading = adcdac.read_adc_voltage(1, 0)
#print("%0.3f counts" %i)
# Vdrop @ shunt = voltage_reading/gain
# Current = Vdrop/Rshunt
calc_current = (voltage_reading/gain)/shunt_resistor
print("%.3f volts driven, %.3f volts seen" %(voltage, voltage_reading))
print("Calculated current is %.5f mA \n" %(calc_current*1000))
#save test results
count = count + 1
test_csv.write("%d, %.3f, %.3f, %s\n" %(count, voltage, voltage_reading, calc_current))
voltage = voltage+0.01
time.sleep(0.040)
# ramp down
for i in range (peak, init-1, -1):
adcdac.set_dac_voltage(1, voltage)
# read channel 1 in single ended mode
voltage_reading = adcdac.read_adc_voltage(1, 0)
#print("%0.3f counts" %i)
calc_current = (voltage_reading/gain)/shunt_resistor
print("%.3f volts driven, %.3f volts seen" %(voltage, voltage_reading))
print("Calculated current is %.5f mA \n" %(calc_current*1000))
#save test results
count = count + 1
test_csv.write("%d, %.3f, %.3f, %s\n" %(count, voltage, voltage_reading, calc_current))
voltage = voltage-0.01
time.sleep(0.040)
raw_input("press [Enter] to set DAC to 0 volts")
adcdac.set_dac_voltage(1, 0)
test_csv.close()
upload_file(csv_filename)
