class TempTest(FwTest):
Tmin = 30
Tmax = 30 + 256 + 512 - 1
def setUp(self):
FwTest.setUp(self)
count = 100
self.Pt = Pt(1.0)
Rmin = self.Pt.resistance(self.Tmin - 1)
self.Rmin = self.Pt.resistance(self.Tmin)
RmaxA = self.Pt.resistance(self.Tmax - 1)
self.Rmax = self.Pt.resistance(self.Tmax)
RmaxZ = self.Pt.resistance(self.Tmax + 1)
self.R = [0.0, 0.98, 1.0, Rmin, self.Rmin, RmaxA, self.Rmax, RmaxZ]
self.T = [0.0, self.Tmin - 0.05, self.Tmin, self.Tmax - 0.05, self.Tmax, self.Tmax + 0.05]
random.seed()
while count:
count = count - 1
self.R.append(random.random() * (self.Rmax - self.Rmin) + self.Rmin)
self.T.append(random.random() * (self.Tmax - self.Tmin) + self.Tmin)
def test_temp(self):
"""Test input for specified numbers"""
for num in self.R:
exp = 0
if num >= self.Rmax:
exp = 0xFFFF / 20.0
elif num >= self.Rmin:
exp = self.Pt.temperature(num)
cmd = "test:temp? %i" % round(num * (2 ** 14))
self.writeline(cmd)
res = self.readline()
res = int(res) / 20.0
try:
self.assertEqual(round(res * 20), round(exp * 20), cmd + " (res: %f exp: %f" % (res, exp))
except AssertionError:
x = abs(res - exp)
self.assertLess(x, 0.05, cmd + " (res: %f exp: %f" % (res, exp))
def test_temp_res(self):
"""Test input for specified numbers"""
fix_point = 2 ** 14
for num in self.T:
exp = 0
if num >= self.Tmax:
exp = 0xFFFF / fix_point
elif num >= self.Tmin:
exp = self.Pt.resistance(num)
cmd = "test:temp:res? %i" % round(num * 20)
self.writeline(cmd)
res = self.readline()
res = int(res) / fix_point
try:
self.assertEqual(round(res), round(exp), cmd + " (res: %f exp: %f" % (res, exp))
except AssertionError:
x = abs(res - exp)
self.assertLess(x, 0.05, cmd + " (res: %f exp: %f" % (res, exp))
class Pt:
"Compute resistance and temperature fot Pt conductor"
A = 3.908e-3
B = -5.802e-7
def __init__(self, R0):
self.R0 = float(R0)
def temperature(self, R):
"Compute temperature from resistance."
a = 2 * self.R0 * self.B
b = self.R0 * self.A
c = self.R0 - R
return ((-b) + sqrt(b ** 2 - 2 * a * c)) / a
def resistance(self, temp):
"Compute resistance from temperature (°C)."
temp = float(temp)
return self.R0 * (1 + (self.A * temp) + self.B * (temp ** 2))
###### SELF-TEST ######
if __name__ == "__main__":
from pt import Pt
s = Pt(10)
print("R0 = 10{\Omega}")
print("T = Pt(R=13) = %f" % s.temperature(13))
print("R = Pt(T=105°C) = %f" % s.resistance(105))