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from test.helpers.syscmd import SysCommand
import unittest
import serial
import time
class Qamp(unittest.TestCase):
params = None
# varlist: undercurrent, overcurrent
def __init__(self, testname, testfunc, varlist):
self.params = varlist
self._current = 0.0
if "undercurrent" in varlist:
self._undercurrent = varlist["undercurrent"]
else:
raise Exception('undercurrent param inside Qamp must be defined')
if "overcurrent" in varlist:
self._overcurrent = varlist["overcurrent"]
else:
raise Exception('overcurrent param inside Qamp must be defined')
self._vshuntfactor = 16384.0
self._ser = serial.Serial()
self._ser.port = '/dev/ttyUSB0'
self._ser.baudrate = 115200
self._ser.parity = serial.PARITY_NONE
self._ser.timeout = 0
self._ser.writeTimout = 0
self._ser.xonxoff = False
self._ser.rtscts = False
self._ser.dsrdtr = False
super(Qamp, self).__init__(testfunc)
self._testMethodDoc = testname
def __del__(self):
self._ser.close()
def execute(self):
# Open Serial port ttyUSB0
error = 0
try:
self._ser.open()
except:
self.fail("failed: IMPOSSIBLE OPEN USB-SERIAL PORT ( {} )".format(self._ser.port))
error = 1
if error == 0:
# Clean input and output buffer of serial port
self._ser.flushInput()
self._ser.flushOutput()
# Send command to read Voltage at Shunt resistor
# Prepare cmd
cmd = 'at+in?\n\r'
i = 0
# Write, 1 by 1 byte at a time to avoid hanging of serial receiver code of listener, emphasis being made at sleep of 50 ms.
while (i < len(cmd)):
i = i + self._ser.write(cmd[i].encode('ascii'))
time.sleep(0.05)
self._ser.read(1)
# Read, 1 by 1 byte
res = []
while self._ser.inWaiting() > 0: # if incoming bytes are waiting to be read from the serial input buffer
res.append(self._ser.read(1).decode('ascii')) # read the bytes and convert from binary array to ASCII
string = ''.join(res)
string = string.replace('\n', '')
self._current = float(int(string, 0)) / self._vshuntfactor
print(self._current)
# In order to give a valid result it is importarnt to define an under current value
if self._current > float(self._overcurrent):
self.fail("failed: OVERCURRENT DETECTED ( {} )".format(self._current))
if self._current < float(self._undercurrent):
self.fail("failed: UNDERCURRENT DETECTED ( {} )".format(self._current))
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