From fde5429cc8555ec5762996fa65c59c5e797c9a4c Mon Sep 17 00:00:00 2001
From: "remi.clement@inrae.fr" <remi.clement@inrae.fr>
Date: Tue, 25 Oct 2022 17:44:41 +0200
Subject: [PATCH] inj time
---
ohmpi.py | 75 ++++++++++++++++++++++++++++++++++++--------------------
1 file changed, 48 insertions(+), 27 deletions(-)
diff --git a/ohmpi.py b/ohmpi.py
index 038d1372..49c6ab35 100644
--- a/ohmpi.py
+++ b/ohmpi.py
@@ -539,8 +539,6 @@ class OhmPi(object):
if injection_duration is None:
injection_duration = self.pardict['injection_duration']
- start_time = time.time()
-
# inner variable initialization
sum_i = 0
sum_vmn = 0
@@ -556,9 +554,9 @@ class OhmPi(object):
else:
polarity = 1
- # first reset the gain to 2/3 before trying to find best gain
- self.ads_current = ads.ADS1115(self.i2c, gain=2 / 3, data_rate=128, address=0x49)
- self.ads_voltage = ads.ADS1115(self.i2c, gain=2 / 3, data_rate=128, address=0x48)
+ # first reset the gain to 2/3 before trying to find best gain (mode 0 is continuous)
+ self.ads_current = ads.ADS1115(self.i2c, gain=2 / 3, data_rate=128, address=0x49, mode=0)
+ self.ads_voltage = ads.ADS1115(self.i2c, gain=2 / 3, data_rate=128, address=0x48, mode=0)
# turn on the power supply
oor = False
@@ -584,12 +582,24 @@ class OhmPi(object):
self.pin0.value = False
self.pin1.value = False
print('gain current: {:.3f}, gain voltage: {:.3f}'.format(gain_current, gain_voltage))
- self.ads_current = ads.ADS1115(self.i2c, gain=gain_current, data_rate=128, address=0x49)
- self.ads_voltage = ads.ADS1115(self.i2c, gain=gain_voltage, data_rate=128, address=0x48)
+ self.ads_current = ads.ADS1115(self.i2c, gain=gain_current, data_rate=860, address=0x49, mode=0)
+ self.ads_voltage = ads.ADS1115(self.i2c, gain=gain_voltage, data_rate=860, address=0x48, mode=0)
# one stack = 2 half-cycles (one positive, one negative)
pinMN = 0 if polarity > 0 else 2
+
+ # start counter
+ # we sample every 10 ms (as using AnalogIn for both current
+ # and voltage takes about 7 ms). When we go over the injection
+ # duration, we break the loop and truncate the meas arrays
+ # only the last values in meas will be taken into account
+ start_time = time.time()
for n in range(0, nb_stack * 2): # for each half-cycles
+ # sampling for each stack at the end of the injection
+ sampling_interval = 10 # ms
+ self.nb_samples = int(injection_duration * 1000 // sampling_interval) + 1
+ meas = np.zeros((self.nb_samples, 2))
+
# current injection
if (n % 2) == 0:
self.pin0.value = True
@@ -599,19 +609,30 @@ class OhmPi(object):
self.pin1.value = True # current injection nr2
start_delay = time.time() # stating measurement time
- time.sleep(injection_duration) # delay depending on current injection duration
+ #time.sleep(injection_duration) # delay depending on current injection duration
# measurement of current i and voltage u
- # sampling for each stack at the end of the injection
- meas = np.zeros((self.nb_samples, 2))
+ dt = 0
for k in range(0, self.nb_samples):
- # reading current value on ADS channel A0
+ # reading current value on ADS channels
meas[k, 0] = (AnalogIn(self.ads_current, ads.P0).voltage * 1000) / (50 * self.r_shunt)
if pinMN == 0:
meas[k, 1] = AnalogIn(self.ads_voltage, ads.P0).voltage * 1000
else:
meas[k, 1] = AnalogIn(self.ads_voltage, ads.P2).voltage * 1000 *-1
- print(meas)
+ time.sleep(sampling_interval / 1000)
+ dt = time.time() - start_delay # real injection time (s)
+ if dt > (injection_duration - 0 * sampling_interval /1000):
+ break
+
+ # stop current injection
+ self.pin0.value = False
+ self.pin1.value = False
+
+ end_delay = time.time()
+
+ # truncate the meas array if we didn't fill the last samples
+ meas = meas[:k+1:]
# we alternate on which ADS1115 pin we measure because of sign of voltage
if pinMN == 0:
@@ -619,15 +640,11 @@ class OhmPi(object):
else:
pinMN = 0
- # stop current injection
- self.pin0.value = False
- self.pin1.value = False
- end_delay = time.time()
-
# take average from the samples per stack, then sum them all
- # average for all stack is done outside the loop
- sum_i = sum_i + (np.mean(meas[:, 0]))
- vmn1 = np.mean(meas[:, 1])
+ # average for the last third of the stacked values
+ # is done outside the loop
+ sum_i = sum_i + (np.mean(meas[-int(meas.shape[0]//3):, 0]))
+ vmn1 = np.mean(meas[-int(meas.shape[0]//3), 1])
if (n % 2) == 0:
sum_vmn = sum_vmn - vmn1
sum_ps = sum_ps + vmn1
@@ -637,12 +654,14 @@ class OhmPi(object):
# TODO get battery voltage and warn if battery is running low
# TODO send a message on SOH stating the battery level
- end_calc = time.time()
-
- # TODO I am not sure I understand the computation below
- # wait twice the actual injection time between two injection
- # so it's a 50% duty cycle right?
- time.sleep(2 * (end_delay - start_delay) - (end_calc - start_delay))
+
+ # wait once the actual injection time between two injection
+ # so it's a 50% duty cycle
+ print('crenaux (s)', (end_delay - start_delay))
+ print('sleep for (s)', injection_duration - (end_delay - start_delay))
+ time.sleep(dt)
+ #time.sleep(injection_duration) # off time between half-cycles
+# time.sleep(2*(end_delay - start_delay) - (end_calc - start_delay))
if self.idps:
self.DPS.write_register(0x0000, 0, 2) # reset to 0 volt
@@ -666,7 +685,7 @@ class OhmPi(object):
"Ps [mV]": sum_ps / (2 * nb_stack),
"nbStack": nb_stack,
"CPU temp [degC]": CPUTemperature().temperature,
- "Time [s]": (-start_time + time.time()),
+ "Time [s]": (time.time() - start_time),
"Nb samples [-]": self.nb_samples
}
print(d)
@@ -791,6 +810,7 @@ class OhmPi(object):
# # TODO if interrupted, we would need to restore the values
# # TODO or we offer the possiblity in 'run_measurement' to have rs_check each time?
+
@staticmethod
def append_and_save(filename, last_measurement):
"""Append and save last measurement dataframe.
@@ -817,6 +837,7 @@ class OhmPi(object):
w.writerow(last_measurement)
# last_measurement.to_csv(f, header=True)
+
def measure(self):
"""Run the sequence in a separate thread. Can be stopped by 'OhmPi.stop()'.
"""
--
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