def _calibrate_temperature():
"""Routine for calibrating the temperature probe."""
expected_temperature = interfaces.read_user_value(
"Ref solution temperature?")
interfaces.lcd_out("Put probe in sol",
style=constants.LCD_CENT_JUST,
line=1)
interfaces.lcd_out("", line=2)
interfaces.lcd_out("Press 1 to", style=constants.LCD_CENT_JUST, line=3)
interfaces.lcd_out("record value", style=constants.LCD_CENT_JUST, line=4)
# Waits for user to press enter
interfaces.read_user_input()
expected_resistance = analysis.calculate_expected_resistance(
expected_temperature)
actual_temperature, actual_resistance = interfaces.read_temperature()
interfaces.lcd_clear()
interfaces.lcd_out(
"Recorded temperature: {0:0.3f}".format(actual_temperature), line=1)
diff = expected_resistance - actual_resistance
new_ref_resistance = (
constants.TEMPERATURE_REF_RESISTANCE +
diff * constants.TEMPERATURE_REF_RESISTANCE / expected_resistance)
constants.TEMPERATURE_REF_RESISTANCE = float(new_ref_resistance)
# reinitialize sensors with calibrated values
interfaces.lcd_out("{}".format(new_ref_resistance), line=2)
interfaces.setup_interfaces()
def _test_temperature():
"""Tests the temperature probe"""
for i in range(5):
temperature, res = interfaces.read_temperature()
interfaces.lcd_out("Temperature: {0:0.3f}C".format(temperature), 1)
interfaces.lcd_out("Res: {0:0.3f} Ohms".format(res), 2)
interfaces.delay(0.5)
def wait_pH_stable(total_sol, data):
"""
Continually polls probes until pH values are stable
:param total_sol: total amount of HCl added to the solution so far
:param data: list of recorded temperature, pH, and solution volume data so far
:return: mean stable pH value of last 10 values
"""
# keep track of 10 most recent pH values to ensure pH is stable
pH_values = [0] * 10
# a counter used for updating values in pH_values
pH_list_counter = 0
# flag to ensure at least 10 pH readings have been made before adding solution
valid_num_values_tested = False
while True:
pH_reading, pH_volts = interfaces.read_pH()
temperature_reading = interfaces.read_temperature()[0]
interfaces.lcd_out("pH: {0:>4.5f} pH".format(pH_reading), line=1)
interfaces.lcd_out("pH V: {0:>3.4f} mV".format(pH_volts * 1000),
line=2)
interfaces.lcd_out("Temp: {0:>4.3f} C".format(temperature_reading),
line=3)
pH_values[pH_list_counter] = pH_reading
if pH_list_counter == 9:
valid_num_values_tested = True
# Check that the temperature of the solution is within bounds
if (abs(temperature_reading - constants.TARGET_TEMPERATURE) >
constants.TEMPERATURE_ACCURACY):
# interfaces.lcd_out("TEMPERATURE OUT OF BOUNDS")
# TODO output to error log
pass
# Record data point (temperature, pH volts, total HCl)
data.append(
(temperature_reading, pH_volts, total_sol, None, None, None, None))
pH_list_counter = 0 if pH_list_counter >= 9 else pH_list_counter + 1
if (valid_num_values_tested and analysis.std_deviation(pH_values) <
constants.TARGET_STD_DEVIATION):
return pH_reading
interfaces.delay(constants.TITRATION_WAIT_TIME)
def test_mode_read_values(numVals=60, timestep=0.5):
numVals = numVals
timestep = timestep
timeVals = np.zeros(numVals)
tempVals = np.zeros(numVals)
resVals = np.zeros(numVals)
pHVals = np.zeros(numVals)
voltVals = np.zeros(numVals)
for i in range(numVals):
temp, res = interfaces.read_temperature()
pH_reading, pH_volts = interfaces.read_pH()
interfaces.lcd_out("Temp: {0:>4.3f} C".format(temp), line=1)
interfaces.lcd_out("Res: {0:>4.3f} Ohms".format(res), line=2)
interfaces.lcd_out("pH: {0:>4.5f} pH".format(pH_reading), line=3)
interfaces.lcd_out("pH V: {0:>3.4f} mV".format(pH_volts * 1000),
line=4)
interfaces.lcd_out("Reading: {}".format(i), 1, console=True)
timeVals[i] = timestep * i
tempVals[i] = temp
resVals[i] = res
pHVals[i] = pH_reading
voltVals[i] = pH_volts
interfaces.delay(timestep)